Exam 2

#separator:tab #html:true #deck column:1 Human Physiology Test 2 Book Notes The ___ is used to calculate the equilibrium potential for an ion at a given concentration difference across a membrane, assuming that the membrane is permeable to that ion. "Nernst <img src=""16943858140942814825121760375967144559176835824024.jpg"">" Human Physiology Test 2 Electrochemical gradients are important for... Action potentials and Resting Membrane Potentials Human Physiology Test 2 What are the two main characteristics of the Nervous System? It is rapid and specific Human Physiology Test 2 Examples of common Peripheral nerves median nerve, sciatic nerve, radial nerve, femoral nerve, vagus nerve Human Physiology Test 2 What are the three major parts of the CNS? Brain, Brain Stem (Midbrain, Pons, Medulla Oblongata), Spinal Cord Human Physiology Test 2 What are the Neurosciences? Neuroanatomy, Neurophysiology, Neurochemistry, Neuropathology, Neuropharmacology, Clinical Neurology, Psychology, Psychiatry, Cell Biology Human Physiology Test 2 How many pairs of peripheral nerves do we have? 43 Human Physiology Test 2 The Vagus nerve is... and provides organ systems with... nerve 10, the majority of the bodie's parasympathetic impulses.  cranial Human Physiology Test 2 A Plexus is where... nerve fibers from different spinal nerves are sorted and recombined, so that all fibers going to a specific body part are put together in one nerve. Examples include the Brachial plexus, lumbsacral plexus, and cervical plexus Human Physiology Test 2 We have ___ pairs of spinal nerves __ cervical __ thoracic __ lumbar __ sacral __ coccygeal 31, 8,12, 5, 5, 1 Human Physiology Test 2 If we have 31 pairs of peripheral nerves and 12 pairs of cranial nerves... 43 pairs of peripheral nerves Human Physiology Test 2 How much cardiac output goes to the brain at rest? How many mLs of blood does the brain always receive? 16%, 750mL Human Physiology Test 2 A pair of arteries (besides vertebral artery) lead to your brain known as the... carotid arteries (internal and external) Human Physiology Test 2 The ___ does not go into your brain but rather leads to arteries and blood vessles in the face external carotid artery Human Physiology Test 2 The ___ carotid artery leads to the brain internal Human Physiology Test 2 The ___ will often contain the carotid artery, vagus nerve and jugular vein.  carotid sheath Human Physiology Test 2 Even high grade research microscopes have a difficult time viewing the synaptic gap Human Physiology Test 2 This is aka a wave of depolarization action potential Human Physiology Test 2 ___ potentials never travel down an axon. __ potentials travel down the axon. A bunch of 1 can cause 2 Local, action Human Physiology Test 2 make myalin in the  Oligodendrocytes make myelin in the  Scwhann Cells CNS, PNS Human Physiology Test 2 ___ are a subtype of glial cells that make up the majority of cells in the human CNS. They perform metabolic, structural, homeostatic and neuroprotective tasks such as clearing neurotransmitters, stabilizing and regulating the blood-brain barrier, and promoting synapse formation.  Astrocytes Human Physiology Test 2 These cells produce CSF Ependymal cells Human Physiology Test 2 These are astrocytes with phagocytic capabilities Microglia Human Physiology Test 2 This is phenomenon of excitable cells such as nerve and muscle and consist of rapid depolarization followed by repolarization of the membrane potential. These are the basic mechanisms for the transmission of information in the nervous system and in all types of muscle.  Action Potential  Human Physiology Test 2 This is the process of making the membrane potential less negative. The usual resting potential of a cell is negative.  Depolarization Human Physiology Test 2 Cellular and Molecular Neurophysiology involves Biophysics, Synapses, Neurotransmitters, Etc Neurons, Human Physiology Test 2 This the process of making the membrane potential more negative Hyperpolarization Human Physiology Test 2 This involves the study of the whole nervous system and its interactions Systems Level Neurophysiology Human Physiology Test 2 Two parts to the nervous system are... CNS: BrainBrainstem (Midbrain, Pons, Medulla)-Spinal Cord<div>PNS: 43 pairs of Nerves, 12 Cranial, 31 Spinal</div> Human Physiology Test 2 Nerve cell bodies are called soma or perikaryon Human Physiology Test 2 Clusters of peripheral perikaryons are called ganglia Human Physiology Test 2 This is the flow of positive charge into the cell. These currents depolarize the membrane (think the inward flow of Na+).  Inward Flow Human Physiology Test 2 This is the flow of positive charge out of the cell. These currents hyperpolarize the membrane (think K+ flowing out).  Outward Current Human Physiology Test 2 The two types of Potentials in Neurons are.. local and action potentials Human Physiology Test 2 This is the membrane potential at which the occurrence of an action potential is inevitable.  Threshold potential  Human Physiology Test 2 Because the threshold potential is less negative than the resting membrane potential, an ___ is required to depolarize the membrane potential to threshold. inward current Human Physiology Test 2 A cluster of Soma in the CNS is called Nucleii or Nucleus Human Physiology Test 2  At threshold potential, inward sodium currents become larger than the net outward potassium currents. This resulting depolarization becomes ___, giving rise to the ___ of an action potential.  self-sustaining, upstroke Human Physiology Test 2 __ is the portion of the action potential where the membrane potential is positive Overshoot Human Physiology Test 2 ___ or hyperpolarizing afterpotential is that portion of the action potential following repolarization where the membrane potential is actually more negative than it is at rest.  Undershoot Human Physiology Test 2 Nerve fiber usually refers to an...  axon Human Physiology Test 2 __ is a period during which another normal action potential cannot be elicited in an excitable cell. These periods can be absolute or relative.  Refractory periods Human Physiology Test 2 What are the three basic characteristics of action potentials1. Stereotypical Size and Shape- Each normal action potential for a given cell type looks identical, depolarizes to the same potential, and repolarizes back to the same resting potential<div>2. Propagation- An action potential at one site causes depolarization at adjacent ones.--> nondecremental</div><div>3. All or none response- An action potential occurs or does not. If it is depolarized in the normal manner, than the occurrence of an action potential is inevitable. On the other hand, if the membrane is not depolarized to threshold no action potential can occur. <div> </div></div> Human Physiology Test 2 Sensory neurons are different from motor neurons in that their  Dendrites are longer than their axons (dendritic tree), their cell bodies have short axons Human Physiology Test 2 The spinal cord begins just past the foramen magnum Human Physiology Test 2 neurotransmitter is __. Motor neurons have long ___ and short ___. The movement axons, dendrites, acetylcholine Human Physiology Test 2 The spinal cord.. doesn't run the full length of the vertebrae. It usually ends around T12-L5 Human Physiology Test 2 " is a neural pathway that controls a reflex. In vertebrates, most sensory neurons do not pass directly into the brain, but synapse in the spinal cord. This allows for faster reflex actions to occur by activating spinal motor neurons without the delay of routing signals through the brain." Reflex arc Human Physiology Test 2 Afferent neurons are () and Efferent are () Sensory, Motor Human Physiology Test 2 Afferent nerve cell bodies collect in a  dorsal root ganglion Human Physiology Test 2 "This is responsible for transmitting somatic motor output from the brain and spinal cord to the body's skeletal muscles" "ventral (anterior) root bundle" Human Physiology Test 2 "The hole in the base of the skull through which the <a class=""rMNQNe"" href=""https://www.google.com/search?sca_esv=571924950&rlz=1C1UEAD_enUS1077US 1077&sxsrf=AM9HkKnfeZoISpQ3YtojBoBSN9ZqORMdA:1696864238956&q=spinal&si=ALGXSlbD4fKmSL7CRU364k GH2u8kZaa13RCRNE01w3LAKG9vYPvO18dir6vHFksiQN_v1vhEdF_daML3uIfy2dGCRJSGvxZyQ%3D%3D&expnd=1"" tabindex=""0"" dataved=""2ahUKEwjjm8fxn-mBAxWDlGoFHbS4AboQyecJegQIKBAL"" style=""text-decoration-line: none; -webkit-tap-highlight-color: rgba(255, 255, 255, 0.1); outline: 0px;"">spinal</a> cord passes." foramen magnum Human Physiology Test 2 "These  neurons are sensory neurons with cell bodies located in spinal and cranial nerve ganglia" "Unipolar (pseudo-unipolar)" Human Physiology Test 2 "<p style=""-webkit-font-smoothing: antialiased; box-sizing: inherit; margin-bottom: 25px; margin-top: 25px; font-size: 18px; line-height: 26px; font-family: "Proxima Nova", "Proxima Nova Fallback", sans-serif;"">These are the <a rel=""noopener noreferrer"" href=""https://bio.libretexts.org/Bookshelves/Introductory_and_General_Biology/Book%3A_Gen eral_Biology_(Boundless)/35%3A_The_Nervous_System/35.02%3A_Neurons_and_Glial_Cells _-_Neurons"" data-type=""URL"" dataid=""https://bio.libretexts.org/Bookshelves/Introductory_and_General_Biology/Book%3A_Gener al_Biology_(Boundless)/35%3A_The_Nervous_System/35.02%3A_Neurons_and_Glial_Cells__Neurons"" target=""_blank"" class=""content-link css-1pg8eb5"" style=""-webkit-font-smoothing: antialiased; box-sizing: inherit; background-color: transparent; cursor: pointer; border-color: currentcolor;"">most common</a> type of neurons in the human body. They are present throughout a person’s <a href=""https://www.medicalnewstoday.com/articles/307076"" class=""content-link css-1pg8eb5"" style=""-webkit-font-smoothing: antialiased; box-sizing: inherit; background-color: transparent; cursor: pointer; border-color: currentcolor;"">CNS</a>, including the brain and associated nerves in the <a href=""https://www.medicalnewstoday.com/articles/327450"" data-type=""URL"" dataid=""https://www.medicalnewstoday.com/articles/327450"" class=""content-link css-1pg8eb5"" style=""-webkit-font-smoothing: antialiased; box-sizing: inherit; background-color: transparent; cursor: pointer; border-color: currentcolor;"">autonomic nervous system</a>. These have the <a rel=""noopener noreferrer"" href=""https://bio.libretexts.org/Bookshelves/Introductory_and_General_Biology/Book%3A_Gen eral_Biology_(Boundless)/35%3A_The_Nervous_System/35.02%3A_Neurons_and_Glial_Cells _-_Neurons"" data-type=""URL"" dataid=""https://bio.libretexts.org/Bookshelves/Introductory_and_General_Biology/Book%3A_Gener al_Biology_(Boundless)/35%3A_The_Nervous_System/35.02%3A_Neurons_and_Glial_Cells__Neurons"" target=""_blank"" class=""content-link css-1pg8eb5"" style=""background-color: transparent; text-align: var(--bs-body-text-align); -webkit-font-smoothing: antialiased; box-sizing: inherit; cursor: pointer; border-color: currentcolor;"">highest</a> number of structures extending from the cell body. There is only one axon, but each cell has many dendrites, making it easier for the neuron to exchange information." Multipolar neurons Human Physiology Test 2 "<ol class=""eQJLDd"" style=""margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding: 0px 0px 0px 20px; display: flex; flex-direction: column; color: rgb(189, 193, 198); font-family: Roboto, arial, sans-serif; font-size: medium; background-color: rgb(32, 33, 36);""><li jsname=""gskXhf"" style=""margin: 0px; padding: 0px; list-style: none;""><div class=""vmod""><div class=""thODed"" style=""padding-top: 8px;""><div jsname=""cJAsRb"" class=""wHYlTd sY7ric"" data-topic="""" style=""font-size: 14px; line-height: 16px;""><div style=""margin-left: 20px;""><div class=""wHYlTd sY7ric"" style=""line-height: 16px; margin-left: -20px;""><div data-dobid=""dfn"" style=""display: inline;"">an <a class=""rMNQNe"" href=""https://www.google.com/search?sca_esv=571924950&rlz=1C1UEAD_enUS1077US 1077&sxsrf=AM9HkKkVfGVAkfypUySOLOf9pGzIl_rzqw:1696864417836&q=encapsul ated&si=ALGXSlb91IXEiYApD91csfAulari75iuD2Ynd2ZoWtfnVZ1oCEjovrKvg54aWyqnmpH1MJbJvd14T7jjxVWXo0DbP7yQfNa0strnEDJDhWPHsLaxgMtD6o%3D&exp nd=1"" tabindex=""0"" dataved=""2ahUKEwiOke3GoOmBAxXIk2oFHSMpDsoQyecJegQIDhAL"" style=""text-decorationline: none; -webkit-tap-highlight-color: rgba(255, 255, 255, 0.1); outline: 0px;"">encapsulated</a> ending of a <a class=""rMNQNe"" href=""https://www.google.com/search?sca_esv=571924950&rlz=1C1UEAD_enUS1077US 1077&sxsrf=AM9HkKkVfGVAkfypUySOLOf9pGzIl_rzqw:1696864417836&q=sensory &si=ALGXSlYwkgxrHbbJwcOTTqB6ethkRCOmGtPV7Z8_cu6QQrUHbDMlwDBLqI4pOKwbUha2tdBcJg7Y19aTQB5 E9RNFi9QnZRurQ%3D%3D&expnd=1"" tabindex=""0"" dataved=""2ahUKEwiOke3GoOmBAxXIk2oFHSMpDsoQyecJegQIDhAM"" style=""text-decorationline: none; -webkit-tap-highlight-color: rgba(255, 255, 255, 0.1); outline: 0px;"">sensory</a> nerve that acts as a <a class=""rMNQNe"" href=""https://www.google.com/search?sca_esv=571924950&rlz=1C1UEAD_enUS1077US 1077&sxsrf=AM9HkKkVfGVAkfypUySOLOf9pGzIl_rzqw:1696864417836&q=receptor &si=ALGXSlY2XXqfLjvIaFfTE-GUlBx5tdCmWeS2K0xmxXalwwT31GLKiOPEEFHNeWbj77FHWMnmtTkEz0ElpfKDk8_ifrAM2Y-hg%3D%3D&expnd=1"" tabindex=""0"" dataved=""2ahUKEwiOke3GoOmBAxXIk2oFHSMpDsoQyecJegQIDhAN"" style=""text-decorationline: none; -webkit-tap-highlight-color: rgba(255, 255, 255, 0.1); outline: 0px;"">receptor</a> for pressure and vibration.</div></div></div></div></div></div></li></ol>" pacinian corpuscle Human Physiology Test 2 "These consist of a cutaneous nerve ending responsible for transmitting the sensations of fine, discriminative touch and vibration." "Meissner <gbubble jscontroller=""QVaUhf"" data-ci="""" data-du=""200"" data-tp=""5"" jsaction=""R9S7w:VqIRre;"" jsshadow=""""><span jsname=""d6wfac"" class=""c5aZPb"" dataenable-toggle-animation=""true"" data-extra-container-classes=""ZLo7Eb"" data-hover-hidedelay=""1000"" data-hover-open-delay=""500"" data-send-open-event=""true"" data-theme=""0"" data-width=""250"" role=""button"" tabindex=""0"" jsaction=""vQLyHf"" jsslot="""" dataved=""2ahUKEwiw2dThoOmBAxXKnGoFHYrxBJEQmpgGegQIIxAD"" style=""outline: 0px;"">corpuscles</g-bubble> " Human Physiology Test 2 The end of the axon is called the  synaptic button Human Physiology Test 2 "a bundle of structures, such as <a class=""rMNQNe"" href=""https://www.google.com/search?sca_esv=571924950&rlz=1C1UEAD_enUS1077US 1077&sxsrf=AM9HkKkoDU57PKnoJcJ3j23hjU3sgwmzoA:1696864610852&q=nerve& amp;si=ALGXSlanL1aSLkbkKVKYTZ8siJOevsXPg9fmfhHMTCZjgco1tFWbYLSGEan3nK2cOyh _cNpeZs4ibNsW-Izh0-fISXMoDwKB2w%3D%3D&expnd=1"" tabindex=""0"" dataved=""2ahUKEwip-fGioemBAxUklWoFHRZUDKsQyecJegQIJxAO"" style=""text-decoration-line: none; -webkit-tap-highlight-color: rgba(255, 255, 255, 0.1); outline: 0px;"">nerve</a> or muscle <a class=""rMNQNe"" href=""https://www.google.com/search?sca_esv=571924950&rlz=1C1UEAD_enUS1077US 1077&sxsrf=AM9HkKkoDU57PKnoJcJ3j23hjU3sgwmzoA:1696864610852&q=fibers& amp;si=ALGXSlbD4fKmSL7CRU364kGH2u8kX9c2h0unJQ2I44XPnJnDTu5l8FH8F0dnpL92ApseycmQ1S2lmhpvi_ZO2ioP8KgIpt04Q%3D%3D&expnd=1"" tabindex=""0"" data-ved=""2ahUKEwip-fGioemBAxUklWoFHRZUDKsQyecJegQIJxAP"" style=""textdecoration-line: none; -webkit-tap-highlight-color: rgba(255, 255, 255, 0.1); outline: 0px;"">fibers</a>" fasicles Human Physiology Test 2 "This is mainly composed of neuronal cell bodies and unmyelinated axons. Axons are the processes that extend from neuronal cell bodies, carrying signals between those bodies. These axons are mainly unmyelinated, meaning they are not covered by a whitish-colored, fatty protein called myelin. This found on the inside of the spine and on the outside of the brain. " grey matter Human Physiology Test 2 "This is made up of a large network of nerve fibers (axons) in your brain that allows the exchange of information and communication between different areas of your brain. Its found on the outside of the spine and the inside of the brain. " White matter Human Physiology Test 2 ALS attacks the  roots of the spinal cord Human Physiology Test 2 Polio could attack the ___ which caused kids to be on the iron lung.  Phrenic nerve (diaphragm doesn't work anymore) Human Physiology Test 2 What is the purpose of the nernst equation It is designed to calculate the equilibrium potential for one individual ion Human Physiology Test 2 Ionic hypothesis  the transfer of nerve impulses is due to the flux of ions Human Physiology Test 2 What is the Goldman Hodgkin Katsz Equation "<img alt=""Introduction"" src=""goldman.gif""> k= RT/F Vm can be swapped for RMP as well <ul><li>Vm is the membrane potential. This equation is used to determine the resting membrane potential in real cells, in which K+, Na+, and Cl- are the major contributors to the membrane potential. Note that the unit of Vm is the Volt. However, the membrane potential is typically reported in millivolts (mV). If the channels for a given ion (Na+, K+, or Cl-) are closed, then the corresponding relative permeability values can be set to zero. For example, if all Na+ channels are closed, pNa = 0.</li><li>R is the universal gas constant (8.314 J.K1.mol-1).</li><li>T is the temperature in Kelvin (K = °C + 273.15).</li><li>F is the Faraday's constant (96485 C.mol-1).</li><li>pK is the membrane permeability for K+. Normally, permeability values are reported as relative permeabilities with pK having the reference value of one (because in most cells at rest pK is larger than pNa and pCl). For a typical neuron at rest, pK : pNa : p Cl = 1 : 0.05 : 0.45. Note that because relative permeability values are reported, permeability values are unitless.</li><li>pNa is the relative membrane permeability for Na+.</li><li>pCl is the relative membrane permeability for Cl-.</li><li>[K+]o is the concentration of K+ in the extracellular fluid. Note that the concentration units for all the ions must match.</li><li>[K+]i is the concentration of K+ in the intracellular fluid. Note that the concentration units for all the ions must match.</li><li>[Na+]o is the concentration of Na+ in the extracellular fluid. Note that the concentration units for all the ions must match.</li><li>[Na+]i is the concentration of Na+ in the intracellular fluid. Note that the concentration units for all the ions must match.</li><li>[Cl-]o is the concentration of Cl- in the extracellular fluid. Note that the concentration units for all the ions must match.</li><li>[Cl-]i is the concentration of Cl- in the intracellular fluid. Note that the concentration units for all the ions must match.</li></ul>" Human Physiology Test 2 Conductance= 1/resistance Human Physiology Test 2 Ohm's law V=IR Human Physiology Test 2 Depolarization This step makes the cell less polar (membrane potential gets smaller as ions quickly begin to equalize the concentration gradients) . Voltagegated sodium channels at the part of the axon closest to the cell body activate, thanks to the recently depolarized cell body. This lets positively charged sodium ions flow into the negatively charged axon, and bring the change cell potential.  Human Physiology Test 2 Depolarization actually ____ equilibriating the cell potential as the action potential pass through. This means that the cell potential actually becomes positive.  overshoots Human Physiology Test 2 <ol><li>This step brings the cell back to resting potential. The inactivation gates of the sodium channels close, stopping the inward rush of positive ions. At the same time, the potassium channels open. There is much more potassium inside the cell than out, so when these channels open, more potassium exits than comes in. This means the cell loses positively charged ions, and returns back toward its resting state.  </li></ol> repolarization Human Physiology Test 2 <div>This step follows repolarization and makes the cell more negative than its typical resting membrane potential. As the action potential passes through, potassium channels stay open a little bit longer, and continue to let positive ions exit the neuron. This means that the cell temporarily ___, or gets even more negative than its resting state. As the potassium channels close, the sodium-potassium pump works to reestablish the resting state. </div><div><div><div><div> </div></div></div></div> hyperpolarization Human Physiology Test 2 action potentials work on an... Human Physiology Test 2 local anesthetics work by  sodium channels so action potentials can't fire. all or none basis  inhibiting voltage gated Human Physiology Test 2 Hyperkalemic cells are initially ____ but eventually become ___. When K amounts in the blood are higher--> K doesn't want to diffuse out of the cell. This causes...... hyperexcitable, hypoexcitable, action potentials to not be able to fire because the cell can never reach resting membrane potential.  Human Physiology Test 2 what are the three type of channels that are important in excitable cells Voltage- gated Na channels Voltage- gated K channels K Leak Channels Human Physiology Test 2 -55 mV is the ___ needed for voltage gated sodium channels to open to initiate an action potential.  At +40mV the __ occurs -70mV is ____ As a way to restore equilibrium, the neuron will open K voltage channels and potassium will leave the cell in massive amounts until it reaches a potential of -85 mV. This is called repolarization and the final state it reaches is called ___ threshold potential action potential rmp Hyperpolarization Human Physiology Test 2 what are the two cable properties.....  These are the electrotonic properties of neurons that underlie the spread of electrical current.  Tau= Rm Cm and  Lambda= sqrt(Rm/Ri) Human Physiology Test 2 What is the time constant equation "<img alt=""Experiment: Comparing Speeds of Two Nerve Fiber Sizes"" src=""paste9d0c2ac823527ed723bb1d97a5f273a5278d98cd.png""> This is the amount of time it takes following the injection of current for the potential to change 63% of its final value. This means that the Time constant indicates that how quickly a cell membrane depolarizes in response to an inward current or quickly it hyperpolarizes in response to an outward current. " Human Physiology Test 2 When membrane Resistance is high... current does not readily flow across the cell membrane, which makes it difficult to change the membrane potential, thus increasing Tau Human Physiology Test 2 The second factor affecting the Time constant is membrane capacitance (Cm) which ___. When this is too high, the time constant is increased because the injected current must first discharge the membrane capacitor before it can depolarize the membrane.  ability of the cell to store charge. Human Physiology Test 2 Myelinate exhibit ___ whereas unmyelinated axons do not.  saltatory conduction Human Physiology Test 2 Saltatory conduction is  the rapid method by which nerve impulses move down a myelinated axon with excitation occurring only at nodes of Ranvier Human Physiology Test 2 The time constant is highest (takes the longest) when... RM and CM are high Human Physiology Test 2 What is the length constant equation? What does it represent? "<img alt=""Experiment: Comparing Speeds of Two Nerve Fiber Sizes"" src=""Byb_mgnlgn_pic6a_v2.png""> The length constant indicates how far a depolarizing current will spread along a nerve. The longer the length constant, the farther the current spreads down the nerve fiber. " Human Physiology Test 2 The length constant will be largest when the diameter of the nerve is large, when membrane resistance is high, and when internal resistance is low Human Physiology Test 2 What are the two types of synapses in neurons chemical synapses and electrical synapses Human Physiology Test 2 electrical synapses are connected to their target cell via ___. These connections are formed by large amounts of proteins called ___ which form cell to cell highways called __. This allows for the cell to cell transfer of ions without the use of a neurotransmitter.  Gap junctions, Connexins, Connexons Human Physiology Test 2 ___ synapses occur between a neuron and an excitable cell where a neurotransmitter is secreted at the terminus of an action potential. These NTs are taken up by their receiving cells which causes a response.  Chemical Human Physiology Test 2 Action potentials activate ____ which causes a massive influx of Calcium into the neuron. This causes membrane fusion, which results in the release of NTs into the synaptic gap to be taken up be receptors at the ___. voltage gated calcium channels, motor end plate Human Physiology Test 2 ___ helps vesicles fuse Synaptobrevin Human Physiology Test 2 a peripheral motor neuron Human Physiology Test 2 Neuro-Muscular Junction is specifically NMJ stands for a skeletal muscle and Neuromuscular Junction Human Physiology Test 2 Acetylcholine is made from  AcetylCoA and Choline Molecules Human Physiology Test 2 Excitation of the Neuron will cause the budding off of synaptic vesicles full of acetylcholine. Each vesicle has ___ acetylcholine molecules.  5000 Human Physiology Test 2 degranulation Human Physiology Test 2 The influx of Calcium causes  membrane fusion and vesicle The muscle side of the NMJ is the  Motor end plate Human Physiology Test 2 Another name for an action potential is a wave of depolarization Human Physiology Test 2 Motor endplates also experience action potentials because Acetylcholine causes the rapid influx of sodium Human Physiology Test 2 Each muscle fiber is  ennervated individually  Human Physiology Test 2 Motor unit is  an axon and the skeletal muscles it ennervates Human Physiology Test 2 Sliding filament theory is the theory that the functional unit of skeletal muscle is __ the sarcomere and they all contract and recede together Human Physiology Test 2 The sarcoplasmic Reticulum is a place for the skeletal muscle to store-->  calcium Human Physiology Test 2 A bundle of muscle fibers is called a  myofibril Human Physiology Test 2 These exists between the two terminal cisternae. This is called  t-tubule Human Physiology Test 2 At rest the cell membrane is approximately ___. The ___ is high and K channels are almost fully open, allowing K ions to diffuse out of the cell down the existing concentration graident. This creates a diffusion potential, which drives the membrane toward the K equilibrium potential. The conductance of ___ is also high and at rest, the cell is near its equilibrium. At rest, the conductance of ___ is low and thus resting potential is far from its equilibrium potential.  -70 to -80 mV K conductance or permeability is high Cl Na Human Physiology Test 2 During the ____, an inward current, usually the result of current spread from action potentials at neighboring sites, causes  depolarization of the nerve cell membrane to threshold, which occurs at approximately ___. This initial depolarization causes rapid opening of the ___ of the sodium channels, and the sodium conductance increases and becomes even higher than the potassium conductance resulting in an inward sodium current (it doesn't reach the equilibrium potential of __) Upstroke of the action potential, -60mV, activation, +65mV Human Physiology Test 2 ___ and ___ block voltage sensitive- sodium channels and prevent the occurance of action potentials.  Tetrodotoxin, and lidocaine Human Physiology Test 2 During the ____, the upstroke is terminated and the membrane potential repolarizes to the resting level.  Repolarization of the action potential Human Physiology Test 2 What are the two steps of repolarization?  1. Inactivation gates close which closes the Na channels and terminates the upstroke  2. Depolarization opens K channels, and and increases K conductance, resulting in a outward current Human Physiology Test 2  ___ blocks the opening of voltage gated K channels, the outward K current, and repolarization.  Tetramethylammonium Human Physiology Test 2 During this brief period following repolarization, the K conductance is higher than at rest, and the membrane potential is driven even closer to the K equilibrium potential. Eventually the K conductance returns back to the resting level, and the membrane potential depolarizes slightly, back to the resting membrane potential. The membrane is now reset.  Hyperpolarizing afterpotential (undershoot) Human Physiology Test 2 A voltage gated ____ is responsible for the upstroke of the action potential in nerve and skeletal muscle. It is an integral membrane consisting of a large alpha and two beta subunits.  sodium channel Human Physiology Test 2 In voltage gated sodium channels, sodium ions flow through the ___, if the ___. central pore, gates are open Human Physiology Test 2 Activation gates on a voltage gated sodium channel open quickly in response to ___. The inactivation gates _____ in response to depolarization albeit, slowly depolarization, close Human Physiology Test 2 What are three combinations of Sodium channel gates  1. Closed, but available (resting potential) (activation closed and inactivation are open) 2. Open, upstroke (upstroke) (both open) 3. Inactivated (peak of action potential) (Inactivation gates close, and activation gates are open) Human Physiology Test 2 This overlaps with almost the entire duration of the action potential. During this period, no matter how great the stimuls, another action potential cannot be generated. The inactivation gates on sodium are closed.  Absolute Refractory Period Human Physiology Test 2 This period begins at the end of the absolute refractory period and overlaps primarily with the period of the hyperpolarizing afterpotential. During this period an action potential can be elicited but only if a great than usual depolarizing current is applied. The basis for this is the higher K conductance than is present at rest. Because the membrane potential is closer to the K equilibrium potential, more inward current is needed to bring the membrane to threshold.  Relative Refractory Human Physiology Test 2 This process occurs when a nerve or muscle cell is depolarized too slowly or is held at a depolarized level (threshold) without an action potential being fired. It is the result of the closing of inactivation gates during depolarization. If depolarization occurs slowly enough, the Na channels close and remain closed. Upstroke cannot occur because there are insufficeint Na channels to facilitate inward current. This is seen in persons that have Hyperkalemia.  Accomodation Human Physiology Test 2 Explain the muscle weakness that results from Hyperkalemia  The resting potential of muscle cells is determined by the gradient for K+ across the cell membrane. At rest the cell is very permeable to K and it diffuses down its gradient. The larger the K concentration gradient, the greater the negativity in the cell. This K diffusion potential is responsible for the resting membrane potential of the cell. The larger the K concentration gradient, the greater the negativity in the cell. When a patient is hyperkalemic, it makes the cell consistently depolarized. This means that sodium gates are consistently accomodated, which causes muscle weakness.  Human Physiology Test 2 Propagation of action potentials down a nerve or muscle fiber occurs by the spread of __ from active regions to adjeacent inactive regions.  local currents Human Physiology Test 2 What are the two mechanisms that increase the conduction velocity along a nerve... 1. Increasing a nerve diameter- Internal resistance is inversely proportional to cross-sectional area. Larger the fiber the lower the resistance. (Lowers Ri, larger lambda (length constant)) 2. myelination- it is a lipid insulator that decreases membrane resistance and decreases membrane capacitance. The increased resistance, forces current to flow one way and the decreased membrane capacitance lowers the time constant. This leads to increased conduction velocity.  Human Physiology Test 2 If the entire nerve were coated with myelin, no action potentials could occur. There are breaks in the myelin sheath called ___. At these nodes the membrane resistance is low and action potentials can fire. This process of jumping from node to node is called... Nodes of Ranvier, saltatory conduction.  Human Physiology Test 2 Multiple sclerosis is disease that ___ nerves. This results in a lack of membrane resistance which causes current to leak out. This means that action potentials are sufficiently communicated between nodes of ranvier.  Demyleinates Human Physiology Test 2 This a site where information is transmitted from one cell to another. The information can be either chemical or electrical synapse Human Physiology Test 2 These types of synapses allow current to flow from one excitable cell to the next via low resistance pathways between cells called gap junctions. (intercalated discs) Electrical synapses Human Physiology Test 2 These synapses have a space where chemicals (neurotransmitters) are secreted called the synaptic cleft. Information is released from the presynaptic neuron and is taken up by the posynaptic neuron.  chemical synapse Human Physiology Test 2 The change in membrane potential in a chemical postsynaptic neuron can be either ___ (depolarize) or __ (hyperpolarize). excitatory, inhibitory Human Physiology Test 2 The ___ is the time required for the multiple steps in chemical neurotransmission to occur. Unlike electrical transmisson, chemical neurotransmission is ___. synaptic delay, unidirectional Human Physiology Test 2 ___ are the nerves that innervate muscle fibers motor neurons Human Physiology Test 2 A ___ comprises a single motorneuron and the muscle fibers it innervates.  motor unit Human Physiology Test 2  is an essential process in muscle physiology, responsible for linking electrical signals from the somatic nervous system (action potentials) to mechanical muscle contractions Excitation-Contraction Coupling Human Physiology Test 2 They synaptic cleft is only ___ wide so we had to use a ___ in order to confirm its size.  few nm, transmission electron microscope Human Physiology Test 2 Muscle cell plasma membranes are sometimes called ___. Sarcolemma Human Physiology Test 2 Each muscle cell has a special smooth er called the Smooth ER Human Physiology Test 2 Binding of ach to the motor end plate causes calcium release from the ___ into the muscle cell.  sarcoplasmic reticulum Human Physiology Test 2 What are the two types of cholinergic receptors found at the motor end plate Nicotinic, Muscvanivic Human Physiology Test 2 This enzyme breaks down acetylcholine and is made up by __, acetyl choline eaterase Human Physiology Test 2 ___ are organophopasgaes, esterine physostigmine Anticholineestarases Human Physiology Test 2 The basment membrane is the:: -__ Basao llamina, Reticuar lamina Human Physiology Test 2 The __ is stregically is stragecically plasced so based so it can __.  diaphragm, be used to help you breathe Human Physiology Test 2 Types of muscle fiber Type 1- Slow Twitch Type IIA- Fast Twitch oxidative, Glycolytic Type II B, Fast Twitch, Glycolytic Human Physiology Test 2 What three neurotransmitters are considered catecholamines dopamine, epinephrine, and noreepinephrine Human Physiology Test 2 What is dopamine produced  in the midbrain (substania nigra) Human Physiology Test 2 Where are the catecholemines norepinephrine and epinephrine produced adrenal medulla Human Physiology Test 2 The adrena cortex is made up of what three zones and it is responsible for.. Zona GLomerulosa Zona Reticularis Zona Fasciculata Creating Aldosterone Human Physiology Test 2 These cells produce catecholemines from Tyrosine.  Chrommafin cells of the Adrenal medulla Human Physiology Test 2 PNMT does what It converts Norepinephrine into Epinephrine Human Physiology Test 2  __ of the adrenal medulla secretrions in the human body aere epinephrine,  80% Human Physiology Test 2 Degradation of catecholemines occurs due to what two enzymes Catechol-M-Transferase, monoamine oxidase Human Physiology Test 2 Binding of ACTH will cause the intake of sodium and ___ > This will cause a conformational shift in the T-tubules.T-tubules have voltage sensitive receptors called ___ receptors. The __ receptors make contact with the ryanodine receptors of the __.  potassium, dihydropyridine , Saroplasmic Reticulum/Terminal cisternae Human Physiology Test 2 Every muscle fiber has a ___ nerve branch innervating it. Human Physiology Test 2 The synapse between a motoneuron and a muscle fiber is called the ___  Neuromuscular junction Human Physiology Test 2 What are the sequence of events in neuromusclar transmission  1. Action potential travels down the motoneuron to the presynaptic terminal 2. Depolarization of the presynaptic terminal opens Ca2+ channels and Ca2+ flows into the terminal  3. Membrane fusion occurs, and Ach is extruded into the synapse via excytosis 4. ACh binds to its receptor on the motor end plate 5. Channels for Na and K are opened in the motor end plate  6. Depolarization of the MEP causes action potentials to be generated in the adjacent muscle  7. ACh is degraded to choline and acetate by AChE; Choline is taken back to the presynaptic terminal on an Na+-choline transporter Human Physiology Test 2 Acetylcholine is formed by __ from Acetyl-CoA and choline. It is the neurotransmitters responsible for__. At the end of contraction, it is degraded back into choline and acetate by ___.  choline transferase, Muscle contraction, acetylcholineesterase Human Physiology Test 2 The smallest amount of ACh that can be released is one vesicle worth, this means that the release of ACh is ___.  Quantal (one quantum) Human Physiology Test 2 The motor end plate contains specialized ___ receptors for ACh. Two molecules of ACh bind to the alpha subunits of this receptor and cause a conformational change. When it binds, the conformational change allows the cells to become more permeable to __. Nicotinic, N+/K+ Human Physiology Test 2 When Sodium and potassium channels open at the MEP, ions will begin to flow down their respective gradients (sodium in and potassium out) in attempt to drive the ____ to its equilibrium potential.  end plate potential Human Physiology Test 2 The content of a single synaptic vesicle produces the smallest possible change in membrane potential of the MEP, or the ___. Many of these are required to reach depolarization.  miniature end plate potential (MEPP) Human Physiology Test 2 This agent blocks the release of ACh from pre-synaptic terminals, causing total blockade of neuromuscular transmission, paralysis of skeletal muscle, and death from respiratory failure.  Botulinus Toxin Human Physiology Test 2 This competes with ACh for binding to alpha subunits of the nicotinic receptors on the MEP. In maximum doses it results in paralysis and death.  Curare Human Physiology Test 2 This is a form of Curare used therapeutically to cause relaxation of skeletal muscle during anesthesia. D-Tubocurarine Human Physiology Test 2 This binds irreversibly to ACh receptors. It has been used experimentally to measure the density of ACh on the MEP. alpha-bungarotoxin Human Physiology Test 2 This type of inhibitor, such as neostigmine, prevents the degradation of ACh in the synaptic cleft, and they prolong and enhance the action of ACh at the motor end plate. AChE inhibitors (Anticholinesterases) Human Physiology Test 2 AChE inhibitors can be used in the treatment of ___, which is a disease characterized by skeletal muscle weakness and fatigability, in which ACh receptors are blocked by antibodies. Myasthenia gravis Human Physiology Test 2 The ___ is illustrated by the NMJ, a single action potential in the presynaptic cell, the motoneuron, causes a single action potential in the post synaptic cell, the muscle fiber. One-to-one synapase Human Physiology Test 2 The ____ is uncommon, but is found, for example at the synapses of motoneurons on Renshaw cells of the spinal cord. It is an amplifier of activity. One to many synapse Human Physiology Test 2 The __ is a very common arrangement in the nervous system. Many presynaptic cells converge onto one neuron. If the signals summate enough, then there will be an action potential firing. Many to one synapse Human Physiology Test 2 Excitative postsynaptic signals are ones that __ the membrane. This is done by opening ___, which moves the cell closer to EPP. Depolarize,N and K channels Human Physiology Test 2 Inhibitory postsynaptic signals are ones that ___ the membrane. This is done by opening __. hyperpolarize, Cl- channels. Human Physiology Test 2 This occurs when two or more presynaptic inputs arrive at the same time. If they are the same, it increases, if they are opposite then they cancel. Spatial Summation Human Physiology Test 2 This occurs when two presynaptic inputs arrive at the postsynaptic cell in rapid succession. Because they overlap, they summate. Temporal summation Human Physiology Test 2 These are phenomena that may occur at synapses Facilitation, augmentation, and post-tetanic potentiation Human Physiology Test 2 What are the two parts of the Adrenal Gland Cortex and the Medulla Human Physiology Test 2 What are the three parts of the Adrenal Cortex? Zona Glomerulosa- Aldosterone (Mineralcorticoid) Zona Fasiculata- Cortisol Zona ReticularisAndrostenedione Human Physiology Test 2 What are the three types of tissue that is innervated by the autonomic nervous system.  cardiac muscle, smooth muscle, glandular epithelium Human Physiology Test 2 Sarcomeres are found along the length of __.  Myofibrils Human Physiology Test 2 The boundary between sarcomeres is called ___, and the line directly down the middle is called the M line. Z bands Human Physiology Test 2 Cardiac, skeletal Human Physiology Test 2 Striated muscle always refers to __ or __ never smooth.  The myosin sits on the ___ on the sarcomere A Band  Human Physiology Test 2 In a skeletal muscle the ratio of actin to myosin is __. The ratio in smooth muscle is more like __.  six to 1 10-16 to 1 Human Physiology Test 2 __ is the most favorable site of actin-myosin relationship (as many actins and myosins can bind that can bind will bind) Optimal Interdigitation Human Physiology Test 2 Our musculoskeletal system has many examples of levers in the body.  ___ levers in the body are used to speed the movement of certain things ____ levers in the body are used to increase the force output of certain  Third, first class Human Physiology Test 2 is a muscular contraction in which the length of the muscle does not change. Think spinal posture.  isometric muscle contraction Human Physiology Test 2 There is a difference between pathogenic and normal ___ hypertrophy Human Physiology Test 2 Humans do not exhibit ___ but can exhibit pathogenic hyperplasia.  normal hyperplasia Human Physiology Test 2 What is the connecting factor between facilitation, augmentation, and post-tetanic potentiation In each instance, repeated stimualtion causes the response of teh postsynaptic cell to be greater than expected.  Human Physiology Test 2 __ occurs in response to brief increases in the frequency of nerve stimulation, leading to an increase in the number of quanta released per stimulus.  Facilitation Human Physiology Test 2 __ is due to increased release of neurotransmitter into the synapse caused by accumulation of Ca2+ in the presynaptic terminal.  Potentiation or post-tetanic potentiation Human Physiology Test 2 __ occurs in storage of memories and involves increased release of neurotransmitters from synaptic terminals and increased sensitivity of postsynaptic membranes to the transmitter.  Longterm potentiation Human Physiology Test 2 ___ occurs when repeated nerve stimulation produces a smaller than expected response in the postsynaptic cell. This is the result of the depletion of neurotransmitter stores in the pre-synaptic terminal.  Synaptic fatigue or depression Human Physiology Test 2 What are the criteria needed to designate a substance as a neurotransmitter 1. substance must be synthesized in the presynaptic cell 2. the substance must be secreted by the presynaptic cell when stimulated 3. if the substnace is secreted to the postsynaptic cell at a physiological concentration the response of the postsynaptic cell must mimic the in vivo response.  Human Physiology Test 2 What are the four groups of neurotransmitters? 1. Choline Esters (ACh) Can 2. Amino Acids                Amy  3. Biogenic Amines         Beat 4. Neuropeptides            Nelson? Human Physiology Test 2 What is the only neurotransmitter in the Choline ester group? ACh Human Physiology Test 2 What are the 5 Biogenic Amines Sell His Cat Serotonin, Histamine, Epinephrine, Norepinephrine, Dopamine Human Physiology Test 2 What are the three Amino acid neuro transmitters GABA, Glutamate, and Glycine Human Physiology Test 2 ___ is the only Neurotransmitter used at the NMJ. It is the neurotransmitter released from all preganglionic and most postganglionic neurons in the parasympathetic nervous system. It is also the the neurotransmitter released from presynaptic neurons of the adrenal medulla.  ACh Human Physiology Test 2 What are the three Biogenic amines that are classified as Catecholamines. What amino acid are they derived from? Epinephrine, Norepinephrine, and dopamine. Tyrosine Human Physiology Test 2 In order to make dopamine, Tyrosine must be converted to ____ by ____.  LDOPA, dopa decarboxylase Human Physiology Test 2 If ___ is present in small dense-core vesicles of the nerve terminal, dopamine is converted into ___. If phenylethanolamine-N-methyltransferase (__) is present (with S-adenosylmethionine as the methyl donor) this product is methylated into.  dopamine Beta-hydroxylase, norepinephrine, PNMT, epinephrine Human Physiology Test 2 ___ secret dopamine because the presynaptic nerve terminal contains tyrosine hydroxylase and dopa decarboxylase but not the other enzymes involved in the catecholamine synthesis pathway.  Dopaminergic neurons Human Physiology Test 2 __ secrete norepinephrine because they contain dopamine Beta hydroxylase, in addition to tyrosine hydroxylase and dopa decarboxylase., but not PNMT.  Adrenergic Neurons Human Physiology Test 2 The __ contains the entire catecholamine synthesis pathway; therefore it secretes primarily epinephrine adrenal medulla Human Physiology Test 2 Catecholamines can be degraded via what two pathways? Catechol-O-methyltransferase, Monoamine oxidase Human Physiology Test 2 This is a methylating enzyme which is not found in nerve terminals but is distributed widely in other tissues including the liver. COMT Human Physiology Test 2 This enzyme is located in the presynaptic nerve terminals and catalyzes oxidative damination of catecholamines. If it degrades a neurotransmitter, there must be reuptake of the neurotransmitter from the synapse.  MAO Human Physiology Test 2 The major metabolite of epinephrine is ____ The major metabolite of norepinephrine is __ Both norepinephrine and epinephrine are degraded to __. 1. metanephrine 2. noremetanephrine 3. 3-methoxy-4-hydroxymandelic acid Human Physiology Test 2 This biogenic amine is produced from tryptophan in brain and gastrointestinal tract. Following its release, it may be reused via reuptake or or degraded by MAO to 5-hydroxyindolacetic acid. It serves as a precursor of melatonin in the pineal gland. Serotonin Human Physiology Test 2 These neurons produce serotonin from its tryptophan precursor in the brain and digestive tract.  Serotonergic Human Physiology Test 2 This biogenic amine is synthesized from histidine, which is catalyzed by histidine decarboxylase. It is present in neurons of the hypothalamus, as well as in nonneural tissue in mast cells of the gastrointestinal tract.  Histamine Human Physiology Test 2 This Aminoacid neurotransmitter is the major excitatory NT in the CNS. It plays a significant role in the spinal cord and cerebellum.  Glutamate Human Physiology Test 2 There are four subtypes of glutamate receptors three of them are ___ receptors (ligand gated ion channels) including N-methyl-D-aspartate channel (NMDA) that is widely distributed throughout the central nervous system. The fourth subtype comprises ___ receptors which are coupled via heterotrimeric GTP-binding proteins to ion channels. ionotropic receptors, metabotropic Human Physiology Test 2 This amino acid is an __ neurotransmitter that is found in the spinal cord and brain stem. Its mechanism of action is to increase Cl- conducatnace of the postsynaptic membrane. By increasing Cl-, the membrane is driven closer to the Cl- equilibrium potenitial which makes the postsynaptic membrane more hyperpolarized and inhibited.  glycine Human Physiology Test 2 This is an amino acid and an ___ NT that is distributed widely in the central nervous system in GABAergic neurons. It is synthesized from glutamic acid, and its formation is catalyzed by glutamic acid decarboxylase. Following its release and action, it can either be recycled or degraded by its terminase to enter the citric acid cycle. Unlike the other amino acid NT, this NT does not have any metabolic function.  GABA, inhibitory Human Physiology Test 2 There are two types of GABA receptors on the postsynaptic membrane. ___ is directly linked to a Cl- channel and is ionotropic. It is the site of activation for ___ and __. When stimulated it it increases Cl- conductance and hyperpolarizes the cell.  ___ is directly linked via a G protein to a K+ channel and thus is ____. It increases K+ conductance and hyperpolarizes the postsynaptic cell.  1. GABA (A) receptor, benzodiazepenes, barbituates 2. GABA (B) receptor, metabotropic Human Physiology Test 2 ___ is associated with a GABA deficiency. The disease is characterized by hyperkinetic choreiform movements related to a deficiency of GABA in the projections from the striatum to globus pallidus. The characteristic uncontrolled movments are in part, attributed to lack of GABA-dependent inhibition of neural pathways.  Huntington's Disease Human Physiology Test 2  This is a short-acting inhibitory neurotransmitter in the gastrointestinal tract and the CNS. In the presynaptic nerve terminals, the enzyme NO synthase converts arginine to citrulline and this.  NO (Nitric Oxide) Human Physiology Test 2 NO is a ___ which means that it simply diffuse from the presynaptic terminal into its target cell.  permeant gas Human Physiology Test 2 These are substances that act on the presynaptic cell to alter the amount of neurotransmitter released in response to stimulation. Alternatively it may be cosecreted with a NT and alter the response of the post-synaptic cell to the neurotransmitter.  Neuromodulator Human Physiology Test 2 These, like other hormones, are released from secretory cells (neurons) into the blood to act at a distant site.  Neurohormones Human Physiology Test 2 __ are copackaged and cosecreted from presynaptic vesicles along with the classic NTs. For example, vasoactive intestinal peptide is stored and secreted with ACh, particularly in neurons of the gastrointestinal tract. Somatostatin, enkephalin, neuropeptide Y and neurotensin are secreted with norepinephrine. Substance P and enkephalin are secreted with serotonin.  Neuropeptides Human Physiology Test 2 In contrast to classic neurotransmitters, which are synthesized in presynaptic nerve terminals, neuropeptides are synthesized in the ___ are packaged into secretory vesicles, moved down the axon via axonal transport, and are then secreted.  cell body Human Physiology Test 2 ___ function as neuromodulators in the autonomic and central nervous system.  For example ATP is synthesized in the sympathetic neurons that innervate vascular smooth muscle. It is costored and cosecreted with the regular NT of of these neurons which is norepinephrine. ---> they both cause muscle contractions.  ATP and adenosine (purine) Human Physiology Test 2 Contraction of skeletal muscle is under voluntary or reflex control. Each skeletal muscle cell is innervated by a branch of motoneuron. Action potentials are propagated along the motoneuron, leading to the release of ___, depolarization of the motor end plate, and initiation of action potentials in the muscle fiber. These events refer to a sequence of events called __. ACh, excitation-contraction coupling Human Physiology Test 2 Each muscle fiber behaves as a __, is multi__, and contains myofibrils.  single unit, nucleated. Human Physiology Test 2 Myofibrils are surrounded by ___ and are invaginated by ___. Each myofibril contains interdigitating thick and thin filaments, which are arranged longitudinally and cross-sectionally in __.  SR, transverse tubules (T tubules), sarcomeres Human Physiology Test 2 The __ filaments comprise a large molecular weight protein called myosin, which has six polypeptide chains including one pair of heavy chains and two pair of light chains. The __ chains wrap around each other to form the tail The ___ chains warpo around each other  Thick, heavy, light Human Physiology Test 2 The globular myosin ___ have an actin-binding site, whcih is necessary for cross-bridge formation, and a site that binds and hydrolyzes ATP (myosin ATPase) Head Human Physiology Test 2 The thin filament is composed of three proteins ___, ___, and ___.  actin, tropomyosin, troponin Human Physiology Test 2 ___ is a globular protein and, in this globular form, is called g___. When the globular form of this protein are twisted into an alpha helix, it forms an alpha helix called F__.  Actin Human Physiology Test 2 Actin has many ___. When the muscle is at rest, the myosinbinding sites are covered by tropomyosin so that actin and myosin do not interact. Myosin binding sites  Human Physiology Test 2 This is a filamentous protein that along the groove of each twisted actin filament. At rest, its function is to to block the myosin-binding on actin. If contraction is to occur, this must be moved so that actin and myosin can interact.  Tropomyosin Human Physiology Test 2 This is a complex of three globular proteins (T, I, and C) located at regular intervals along the tropomyosin filaments.  Troponin Human Physiology Test 2 ___ attaches the troponin to tropomyosin.  ___ inhibits the interaction of action and myosin by covering the myosin binding site on actin.  ___ is a Ca2+ binding protein that plays a central role in the initiation of contraction.  Troponin T, Troponin I, Troponin C Human Physiology Test 2 The ___ is the basic contractile unit, and is bounded by z disc to z disc.  sarcomere Human Physiology Test 2 ___ are located in the center of the sarcomere and contain the thick (myosin) filaments, which appear dark when viewed under polarized light. Thick and thin filaments overlap here. These areas are potential sites of crossbridge formation.  A bands Human Physiology Test 2 ___ are located on either side of the A band appear light when viewed under polarized light. They contain the thin (actin) filaments, intermediate filamentous proteins, and Z disks.  I  bands Human Physiology Test 2 The ___ are darkly staining structures that run down the middle of each I band, delineating the end of the sarcomere.  Z band Human Physiology Test 2 The ___ is located in the center of each sarcomere. There are no thin filaments in the bare zone, thus there can be no overlap with thin filaments with head group thick filaments. and thus no cross-bridge group formation in this region.  The __ bisects that bare zone and contains darkly staining proteins that link the central portions of the thickly staining filaments together.  bare zone, M line Human Physiology Test 2 Cytoskeletal proteins establish the architecture of ___, ensuring that thick and thin filaments are aligned correctly and at proper distances with respect to each other.  myofibrils Human Physiology Test 2 ___ link thick and thin filaments, forming a scaffold for the myofibrils and linking sarcomeres of adjacent myofibrils. A system of intermediate filaments holds the myofibrils together. The entire array is anchored to the cell membrane by a protein called __.  Transverse cytoskeletal proteins, dystrophin Human Physiology Test 2 Longitudinal cytoskeletal proteins include two large proteins called titin and nebulin ___ is associated with thick filaments and extends from M lines to Z disks. It passes through the thick filaments, while part of it anchored to the Z disk. As the length of the sarcomere changes, so too does the length of this. This protein also helps center the thick filaments in the sarcomere.  ___ is associated with thin filaments. A  single nebulin molecule extends from one end of the thin filament to the other. It is a moleculer ruler because  it sets the length of thin filaments during their assembly.  Titan Nebulin Human Physiology Test 2 __ anchors the thin filaments to the Z disk.  alpha actinin Human Physiology Test 2 ___ are an extensive network of muscle cell membrane (sarcolemmal membrane) that invaginates deep into the muscle fibers. They are responsible for carrying depolarization from action potentials at the muscle cell surface to the interior of the fiber.  T tubules (transverse tubules) Human Physiology Test 2 T tubules make contact with the ___ of the Sarcoplasmic Reticulum and contain a voltage-sensitive protein called ___.  terminal cisternae, dihydropyridine Human Physiology Test 2 The ___ is an internal tubular structure which is the site of storage of and release of Ca2+ for excitation-contraction coupling. It contains a Ca2+ release channel called the ___.  Sarcoplasmic reticulum (SR), ryanodine Human Physiology Test 2 Ca2+ is accumulated in SR by action of ___ (SERCA) in the SR membrane. It pumps calcium from the ICF of the muscle fiber into the interior of SR, keeping the intracellular Ca2+ low when the the muscle fiber is at rest.  Ca2+ ATPase Human Physiology Test 2 Within the SR, Ca2+ is bound to ___ a low affinity, a high capacity Ca2+ binding protein. By binding Ca2+ in this way, this protein helps maintain a low free Ca2+ concentration inside the SR, thereby reducing reducing the work of SERCA.  Calsequestrin Human Physiology Test 2 What are the steps to Excitation-Contraction Coupling in Skeletal Muscle  1. Action potential in muscle membrane 2. Depolarization of T Tubules 3. Conformational change in dihydropyridine receptors 4. Opens SR Ca2+ release channels (ryanodine receptors) 5. Intracellular calcium concentration increases 6. Calcium binds troponin C 7. Tropomyosin moves and allows interaction of actin and myosin 8. Crossbridge cycling and force-generation 9. Ca2+ reaccumulated by SR Ca2+ ATPase (SERCA)-> relaxation   Human Physiology Test 2 1. Action potentials in the muscle cell membrane are propagated to the __ by the spread of local currents. Thus the __ are continuous with the sarolemmal membrane and carry the depolarization from the surface to the interior of the muscle fiber.  T tubules Human Physiology Test 2 2. Depolarization of the T tubules causes a critical conformational change in their voltage-sensitive ___ receptors. This conformational change opens Ca2+ release channels (__) on the nearby SR.  dihydropyridine, ryanodine receptors Human Physiology Test 2 3. When the ryanodine receptors open, ___ is released from its storage in the SR into the ICF of the muscle fiber, resulting in an ____. At rest, the intracellular free Ca2+ concentration is less than 10^-7 M. After its release its from the SR, intracellular free calcium concentration increases to ___.  calcium, increase in intracellular calcium concentration, between 10^-7 and 10^-6M Human Physiology Test 2 4. ___ on the thin filaments causing a conformational change in the troponin complex. It can bind four calcium per molecule of protein. Because this binding is ___, each molecule of bound Ca2+ increases the affinity of troponin C for the next Ca2+.  Ca2+ binds to troponin C, Cooperative Human Physiology Test 2 5. The ___ causes tropomyosin (which was previously blocking the interaction of actin and myosin) to be moved out of the way so that cross-bridge cycling can begin. When tropomyosin is moved away, the myosin-binding sites on actin, previously covered, are exposed.  conformational change in troponin Human Physiology Test 2 6. With Ca2+ bound to troponinC and tropomyosin moved out of the way, myosin heads can now bind to actin and form so-called ___.  a. At the beginning of the cycle ___ is just released from myosin and no ___ are bound. Myosin is tightly attached to actin in the ___ position. In rapidly contracting muscle, this attached state is brief but, in the absence of __, it is permenant.  cross-bridges ADP, nucleotides, rigor position, ATP Human Physiology Test 2 6b. The binding of the __ to a cleft on the back of the myosin head produces a conformational change in myosin that decreases its affinity for __. Thus myosin is released from the original actin-binding site.  6c. The cleft on the myosin head closes around the bound ATP molecule, producing a further confromational change that causes myosin to be displaced toward ___.  ATP is ____, and it remains attached to myosin.  b. ATP, actin c. the plus end of actin, hydrolyzed to ADP  Human Physiology Test 2 6d. After hydrolyzing ATP and displacing itself, Myosin binds to a new spot on actin. This constitutes the ____. Each cycle walk the myosin head along the actin filament.  6a. Cross-bridge cycling continues, with myosin walking toward the plus end of the actin filament, as long as ____. force-generating or powerstroke Ca2+ is bound to troponin C Human Physiology Test 2 7. ___ occurs when Ca2+ is reaccumulated in the SR by the Ca2+ ATPase of the SR membrane (SERCA). When the intracellular Ca2+ decreases to less than 10^-7 M, there is insufficient Ca2+ for ___. When it is released from troponin C, ____ where it blocks the myosin-binding site on actin. As long as the intracellular Ca2+ is low, cros-bridge cycling cannot occur and the muscle will not relax.  Relaxation, binding to troponin C, tropomyosin returns to its resting position Human Physiology Test 2 The cross-bridge cycle produces ___ at the level of the contractile elements. In order for this force to be transmitted to the muscle surface, the series elastic elements must first be __. As a result, there is a delay in transmission of force from the crossbridges to the muscle surface.  force (tension) stretched out Human Physiology Test 2 Once the cross-bridge cycling has concluded, there is a delay ___, as the series of elastic elements remains stretched out. And thus force transmission to the muscle continues ___ and cross-bridge cycling has ceased.  in the fall of muscle tension, intracellular Ca2+ has fallen Human Physiology Test 2 A single action potential results in the release of a fixed amount of calcium form the SR, which produces a single twitch. The twitch is terminated when the ____. However if the muscle is stimulated repeatedly, there is insufficient ___, and the intracellular Ca2+ concentration never returns to the low levels that exist during relaxation. This results in sustained contraction called ___.  SR reaccumulates this Ca2+, time for the SAR to reaccumulate Ca2+ , tetanus Human Physiology Test 2 The __ in muscle refers to the effect of muscle fiber length on the amount of tension the fiber can develop. The amount of tension is determined for a muscle undergoing an ___ in which the muscle is allowed to develop tension at a preset length (called __) but is not allowed to shorten.  length-tension relationship, isometric contraction, preload Human Physiology Test 2 __ tension is the tension developed by simply stretching a muscle to different lengths. (Think of the tension produced in a rubber band as it is progressively stretched to longer lengths) passive Human Physiology Test 2 __ tension is the tension developed when a muscle is stimulated to contract at different preloads. It is the sum of the active tension developed by the crossbridge cycling in the sarcomeres and the passive tension caused by stretching the muscle.  Total tension Human Physiology Test 2 __ is determined by subtracting the passive tension from the total tension. It represents the active force developed during cross-bridge cycling. The unusual relationship between active tension and muscle length is the ___and can be explained by the mechanisms invovled in the cross-bridge cycle.  Active tension, length-tension relationship Human Physiology Test 2 The active tension developed is proportional ____. Therefore the active tension is maximal when there is maximal overlap of thick and thin filaments and maximal possible cross-bridges. When the muscle is stretched to longer lengths, the number of possible cross bridges is ___ and ___ is reduced. Likewise when muscle length is ___, the thin filaments collide with each other in the center of the sarcomere, reducing the ____, and reducing active tension.  to the number of cross-bridges that cycle, reduced, active tension decreased, number of possible cross-bridges Human Physiology Test 2 The ___ describes the velocity of shortening when the force against which the muscle contracts, the ___, is varied.  Force-Velocity, afterload Human Physiology Test 2 In contrast to the length-tension relationship, the ___ is determined by allowing the muscle to shorten. The force, rather than length, is fixed and therefore it is called an ___. The velocity of shortening reflects the ___.  force-velocity relationship, isotonic contraction, speed of cross-bridge cycling Human Physiology Test 2 The effect of afterload on the ____ can be further demonstrated by setting the muscle to a preset length (preload) and then measuring the velocity of shortening at various levels of afterload. velocity of shortening Human Physiology Test 2 __ muscle lack striations which distingusihes it from skeletal and cardiac muscle. This because there are no __. It is found in the walls of hollow organs such as the gastrointestinal tract, the bladder, and the uterus, as well as in the vasculature, the ureters, the bronchioles, and the muscles of the eye.  Smooth, sarcomeres Human Physiology Test 2 The functions of smooth muscle are twofold:  1. to produce __ 2. and to maintain __ motility, tension Human Physiology Test 2 Smooth muscles are classified as ___ or ___, depending on whether the cells are electrically coupled.  1. ___ smooth muscle has gap junctions between cells, which allow for the fast spread of electrical activity throughout the organ followed by a coordinated contraction.  2. ___ smooth muscle has little or no coupling between cells.  unitary or multiunit unitary, multiunit Human Physiology Test 2 __ is present in the gastrointestinal tract, bladder, uterus, and ureter. The smooth muscle in these organs contracts in coordinated fashion because the cells are linked by ___.  Unitary Smooth Muscle, gap junctions Human Physiology Test 2 __ are low-resistance pathways for current flows, which permit electrical coupling between cells.  Gap Junctions Human Physiology Test 2 Unitary smooth muscle is also characterized by spontaneous pacemaker activity or ___. The frequency of ___ sets a characteristic pattern of action potentials within an organ, which then determines the frequency of contractions.  slow waves Human Physiology Test 2 __ is present in the iris, ciliary muscles of the lens, and in the vas deferens. Each muscle fiber behaves as a separate motor unit (similar to skeletal muscle), and there is little or no coupling between cells.  Multiunit smooth cells Human Physiology Test 2 ___ Smooth Muscle Cells are densely innervated by postganglionic fibers of the parasympathetic and sympathetic nervous systems, and it is these innervations that regulate function.  Multiunit Human Physiology Test 2 Smooth muscle cells can undergo both ___ and ___. Skeletal muscle cells and cardiac muscle muscle are ___ which means that skeletal/cardiac muscle are only capabable of __. hyperplasia and hypertrophy.  postmitotic, hypertrophy Human Physiology Test 2 The first third of the human esophagus is __ muscle, the middle third is ___, and the final third is ___.  skeletal muscle, a combination of skeletal and smooth, smooth Human Physiology Test 2 Carnivores have more control over their ___ than we do.  esophagus Human Physiology Test 2 The digestive systems primarily consists of ____ muscle smooth Human Physiology Test 2 ___ muscle is more likely to coordinate voluntary movements. ___ and ___ coordinate involuntary movements.  Skeletal, Cardiac, Smooth Human Physiology Test 2 Motility generally refers to moving things in the body via___ smooth muscle contraction Human Physiology Test 2 In the Urinary tract, the ___ and the ___ are lined with smooth muscle. ureters and urethra Human Physiology Test 2 If the lights go off our eyes __ in order to let in more light. The opposite occurs when the lights come back on and your pupils __. dialates, constrict Human Physiology Test 2 Autonomic nerves ennervate... cardiac muscle, smooth muscle, glands Human Physiology Test 2 Sensory responses often involves ___ muscle (fight or flight response, pupil dilating, etc) smooth Human Physiology Test 2 In smooth muscle there is no ___. Rather, the interaction of actin and myosin is controlled by the binding of Ca2+ to another protein, ___. In turn Ca2+-___ regulates myosin-light-chain kinase, which regulates cross-bridge cycling.  troponin, Calmodulin, Calmodulin Human Physiology Test 2 What are the three ways to stimulate smooth muscle chemical, mechanical, electrical Human Physiology Test 2 There are no ___ or ___ in Smooth Muscle Sarcoplasmic Reticulum or Sarcomeres Human Physiology Test 2 Smooth muscle cells have no ___ or ___. When they contract they simply corkscrew as their contractile filaments are simply layered beneath the cell membrane. They have little indentations called ___ that they many think are like primitive T tubules sarcomere, myofibrils, caveolae Human Physiology Test 2 The ___ stimulates the Diaphragm to contract Phrenic nerve Human Physiology Test 2 The enteric nervous system is a branch of the  autonomic nervous system Human Physiology Test 2 This is a local circuitry of neurons and ganglia which is situated within the gut wall (from esophagus to the rectum). It is situated within the submucosa and innervates the smooth muscle of the gut. submucosal plexus Human Physiology Test 2 This is principally responsible for the peristaltic movement of the bowels and gut. It is a part of the enteric nervous system.  Myenteric plexus Human Physiology Test 2 "These are the <a href=""https://www.google.com/search?sca_esv=579769985&rlz=1C1UEAD_enUS1077US 1077&sxsrf=AM9HkKlLzlByY-VcoSR4V2e6TvDWCtAyw:1699286009044&q=involuntary&si=ALGXSlY7Tk5u3AnUd39hr4eAN0grOQKURhT Sd305vxJczTJFlFItNZFZY9YBbrSR00pvIlnGMwrrHrbP13tQYTfUEdR9JuMeD8vZCYEVgmMMg wdWSQ_MzpE%3D&expnd=1"">involuntary</a> <a href=""https://www.google.com/search?sca_esv=579769985&rlz=1C1UEAD_enUS1077US 1077&sxsrf=AM9HkKlLzlByY-VcoSR4V2e6TvDWCtAyw:1699286009044&q=constriction&si=ALGXSlbsnhJrQT67VON4kgaynbBxaWgV897 4_gm5TLBB5S6NAa3nCVOma6XvlZRYDeL63Q_bBiWYoI4lx96DYTdoa5CosV73Z8p7qugNAF89MU1Ja_BxQw%3D&expnd=1"">constriction</ a> and relaxation of the muscles of the <a href=""https://www.google.com/search?sca_esv=579769985&rlz=1C1UEAD_enUS1077US 1077&sxsrf=AM9HkKlLzlByY-VcoSR4V2e6TvDWCtAyw:1699286009044&q=intestine&si=ALGXSlb6hSjuI-stkeAspHuNXR7xZZGngkJ4rZO3MAVCejIbCCzUNDUpjfZaaJNgfgEbSNyCxfARZP8xYQNH259e_q2WjW5ltCEvcAwGdda_h2mcBtl2c%3D& expnd=1"">intestine</a> or another canal, creating wave-like movements that push the contents of the canal forward." Peristalsis Human Physiology Test 2 What are three divisions of the autonomic nervous system "sympathetic, parasympathic and enteric <img src=""pastecb55f274d4c8125beb4ce8e89ae93ba5308b8a6a.jpg"">" Human Physiology Test 2 The parts of the nervous system that we have control over are called the.. These are generally innervated with __ muscle.  Somatic (voluntary) nervous system. Skeletal Human Physiology Test 2 The parts of the nervous system that we don't have control over are called the __ nervous system They are mainly control with ___ muscle fibers.  autonomic (visceral) nervous system Smooth, cardiac Human Physiology Test 2 The parasympathetic division is also known as the ___.  Craniosacral Outflow Human Physiology Test 2 The sympathetic division is also referred to as the...... Thoracolumbar Outflow Human Physiology Test 2 Parasympathetic is .... Sympathetic is..... Rest and Digest Fight or Flight Human Physiology Test 2 Heart rate above 100 is ... Heart rate below 60 is.... Tachycardia Bradycardia Human Physiology Test 2 Cranial nerve Human Physiology Test 2 Cranial nerve 3 is the... Human Physiology Test 2 Cranial nerve 7 is the Facial nerve Human Physiology Test 2 Cranial nerve 9 is the Glossopharyngeal nerve. Swallowing Oculomotor nerve Human Physiology Test 2 Cranial nerve 10 is the It can decrease _____. Vagus Nerve Heart rate. Human Physiology Test 2 1. Depolarization of smooth muscle opens voltage gated Ca2+ channels open, Ca2+ flows into into the cell down its electrochemical gradient. This influx of Ca2+ from the ECF causes an increase in intracellular Ca2+ concentration. In contrast to skeletal muscle, where ___ are required to produce contraction, in smooth muscle, subthreshold depolarization can open these voltage-gated Ca2+ channels and cause an increase in intracellular Ca2+ concentration. If it reaches threshold, then ___ can occur causing even greater depolarization and even greater opening of voltage-gated ion channels.  Action potentials Human Physiology Test 2 Ca2+ that enters the smooth muscle cells through voltage-gated Ca2+ channels releases additional Ca2+ from the SR (called ___). Thus the rise in intracellular Ca2+ is partly due to Ca2+ entry across the sarcolemmal membrane and partly due to Ca2+ release from intracellular SR stores.  Ca2+-induced Ca2+ release Human Physiology Test 2 2. Two additional mechanisms may contribute to the increase in intracellular Ca2+ concentration: ligand-gated Ca2+ channels and IP3-gated Ca2+ release channels. ___ in the sarcolemmal membrane may be opened by various hormones and NT, permitting the entry of additional Ca2+ from the ECF. ___ in membrane of the SR may be opened by hormones and neurotransmitters. Either of these mechanisms may augment the rise in intracellular Ca2+ concentration caused by depolarization.  Ligand-gated Ca2+ channels IP3-gated Ca2+ release channels Human Physiology Test 2 3. The rise in intracellular Ca2+ concentration causes Ca2+ to bind to __. Like troponin C in skeletal muscle, calmodulin binds four ions of Ca2+ in a cooperative fashion. The Ca2+- ___ complex binds to and activates the ___.  calmodulin, myosin-light-chain kinase Human Physiology Test 2 4. When activated, myosin-light-chain kinase ____ the myosin light chain. When myosin light chain is __, the conformation of the myosin head is altered, greatly increasing its ATPase activity. (In contrast, skeletal muscle myosin ATPase activity is always high.) The increase in myosin ATPase activity allows myosin to bind actin, thus initiating cross-bridge cycling and production of tension. The amount of tension is proportional to the intracellular Ca2+ concentration.  phosphorylates, phosphorylated Human Physiology Test 2 5. Ca2+-calmodulin in addition to the effects on myosin described earlier also has effects on two thin filament proteins, ___ and ___. At low levels of intracellular Ca2+, __ and __ bind actin, inhibiting myosin ATPase and preventing the interaction of actin and myosin. When the interacellular Ca2+ increases, the Ca2+-calmodulin complex leads to phosphorylation of __ and __, releasing their inhibitionof myosin ATPase and facilitating the formation of cross-bridges between actin and myosin.  calponin, caldesmon Human Physiology Test 2 6. ___ of smooth muscle occurs when intracellular Ca2+ concentration falls below the level needed to form Ca2+ calmodulin complexes. A fall in intracellular Ca2+ concentration can occur by a variety of mechanisms including hyperpolarization (which closes voltage-gated Ca2+ channels); direct inhibition of Ca2+ channels by ligands such as __ and __; inhibition of IP3 and decreased release of Ca2+ from SR; and increased Ca2+ ATPase activity in SR. Additionally, ___ of smooth muscle can involve activation of myosin-light-chain phosphatase, which dephosphorylates myosin light chain leading to inhibition of myosin ATPase.  Relaxation, cAMP, cGMP, relaxation Human Physiology Test 2 Steps of Molecular events in contraction of smooth muscle 1. Opening voltage gated Ca2+ channels via ___ or Release of __ due to Hormones and NT 2. ___ release from SR or ___ release from SR 3. Increase in ___ 4. Ca2+ binds to ___ 5. Activation of the ___ kinase 6. The myosin light chains are ___ 7. The __ ATPase is activated 8. Myosin binds to __ 9. ___ begins 10. Tension 1. Depolarization, Hormones/NT, IP3 2. Ca2+ induced Ca2+, IP3 induced Ca2+ release 3. Intracellular calcium 4. Calmodulin 5. myosin light chain 6. Phosphorylated 7. Myosin 8. Actin 9. Crossbridge cycling Human Physiology Test 2 What are the three mechanisms that are involved in Ca2+ entry in smooth muscle Voltage gated Ca2+ channels Ligand gated Ca2+ channels IP3 gated channels Human Physiology Test 2 __ are sarcolemmal Ca2+ channels that open when the cell membrane potential depolarizes. Thus action potentials in the smooth muscle cell membrane cause voltage-gated Ca2+ channels to open, allowing Ca2+ to flow into the cell down its electrochemical potential gradient.  Voltage-gated Ca2+ channels Human Physiology Test 2 __ are present in the sarcolemmal membrane. They are not regulated by changes in membrane potential but by receptor mediated events. Various hormones and NTs interact with specific receptors in the sarcolemmal membrane, which are coupled via a GTP-binding protein (G protein) to the Ca2+ channels. When the channel is open, Ca2+ flows into the cell down its electrochemical gradient.  Ligand Gated Ca2+ channels Human Physiology Test 2 ___ are present in SR membrane. The process begins at the cell membrane, but the source of the Ca2+ is the SR rather than the ECF. Hormones or NT interact with specific receptors on the sarcolemmal membrane. (norepinephrine or a1 receptors). These receptors are coupled, via a G protein, to __. This catalyzes the hydrolysis of phosphatidylinositol 4,5-diphosphate (PIP2) to IP3 and diacylglycerol (DAG). __ then diffuses to the SR, where it opens Ca2+ release channels (similar to ryanodine receptors in skeletal muscle). When these Ca2+ are open, Ca2+ flows from its storage site in the SR into the ICF.  IP3-gated Ca2+ channels, Phospholipase C, IP3 Human Physiology Test 2 In addition to the contractile mechanisms in smooth muscle that depend on changes in intracellular Ca2+ concentration, the degree of contraction also can be regulated by Ca2+-independent mechanisms. For example, in the presence of a constant level of intracellular Ca2+, if there is activation of myosin-light-chain kinase, more cross-bridges will cycle and more tension will be produced ___; conversely, if there is activation of myosin-lightchain phosphatase, fewer cross-bridges will cycle and less tension will produced (__).  (Ca2+ sensitization), (Ca2+ desensitization) Human Physiology Test 2 ___: which is a voluntary motor system under conscious control. Each of its pathways consists of a single motoneuron and the skeletal muscle fibers it innervates. The cell body of the motoneuron is located in the CNS, in either brain or spinal cord, and its axon synapses directly on skeletal muscle, the effector organ. The neurotransmitter acetylcholine is released from presynaptic terminals of the motoneurons and activates nictoninic receptors located on the motor end plates of skeletal muscle. An Action Potential in the motoneuron causes an action potential in the muscle fiber, whcih causes the muscle to contract.  Somatic Nervous system Human Physiology Test 2 The motor efferent nervous system has two components: __ and __ Somatic, autonomic Human Physiology Test 2 The __ is an involuntary system that controls and modulates the functions primarily of visceral organs. Each pathway in the ___ nervous system consists of two neurons: a preganglionic neuron and a postganglionic neuron. The cell body of each preganglionic neuron resides in the CNS. The axons of these preganglionic neurons synapse on the cell bodies of postganglionic neurons in one of several autonomic ganglia located outside the CNS. The axons of the postganglionic neurons than travel to the periphery, where they synapse on visceral effector organs such the heart, bronchioles, vascular smooth muscle, GI, bladder, and genitals. All preganglionic neurons of the ___ nervous system release acetylcholine. Postganglionic neurons release either acetylcholine or norepinephrine or, in some cases, neuropeptides.  Autonomic nervous system Human Physiology Test 2 Preganglionic neurons in the __ originate in the thoracolumbar spinal cord.  Preganglionic neurons in the __ originate in the brain stem and spinal cord.  sympathetic division parasympathetic Human Physiology Test 2 The terms of adrenergic and cholinergic are used to describe neurons of either division (sympthatic division or parasympathetic).  ___ neurons release norepinephrine; receptors for norepinephrine on the effector organs are called __.  These may be activated by norepinepherine, or epinephrine (which is secreted into the circulation by the adrenal medulla).  ___ neurons release acetylcholine (ACh), receptors for this are called ___ receptors.  adrenergic, adrenoreceptor Cholinergic, cholinoreceptors Human Physiology Test 2 Sympathetic Neuron Pathway (Exam Question) Pre-___ neurons always release ___ which then binds to ____ receptors on the cell bodies of post- ___ neurons which runs to target (__ organ). Most postganglionic neurons release either __ which bind to the __ receptors (__), or __ which binds to __ receptors <ul><li>ganglionic, acetylcholine, nicotinic cholinergic, ganglionic, effector</li><li>Norepinephrine, adrenergic, (a1, a2, B1, B2), Ach, muscarinic</li></ul> Human Physiology Test 2 Parasympathetic Pathway (Exam Question) Parasympathetic, Pre-___ neurons release __ which bind to __ receptors on the Post__ neurons. The Parasympathetic post__ neurons, always release __ which bind __ receptors on their __. ganglionic, ACh, nictonic cholinergic, ganglionic ganglionic, ACh, Muscarinic, effector organs Human Physiology Test 2 Adrenal Medulla (ExamQ) The Adrenal Medulla is innervated by the ___ system and its pre__ neurons secrete __. ACh binds to ___ found on the Adrenal Medulla. This releases both ___ and ___ into the blood stream in an (80% to 20%). ___ are the cells in the adrenal medulla that produce EPI and norEPI. When these are released they are considered __ not NT but are, ___ and trigger the fight or flight response. Sympathetic Nervous, ganglionic, ACh Nicotinic cholinergic receptors Epinephrine, Norepinephrine Chromaffin cells  hormones, hormones Human Physiology Test 2 The junctions between postganglionic autonomic neurons and their effectors (target tissues) the ___, are analagous to the neuromuscular junctions of the somatic nervous system.  neuroeffector junction Human Physiology Test 2 Three differences between Neuroeffector Junctions of the Autonomic Nervous System and the Neuromuscular Junctions of Somatic Nervous System.  1. The ___ junction has a discrete arrangement, whereby the effector (skeletal muscle fiber) is innervated by a single motoneuron. The ___ junction form diffuse, branching networks. Beads, or ___, lines these branches and are the sites of NT synthesism storage and release. These beads are therefore analagous to the presynaptic nerve terminals found in the somatic nervous system.  Neuromuscular Junction Neuroeffector Junction, varicosities  Human Physiology Test 2 Three differences between Neuroeffector Junctions of the Autonomic Nervous System and the Neuromuscular Junctions of Somatic Nervous System.  2. In the ___, there is overlap in the branching networks from different postganglionic neurons, such that target tissues may be innervated by many postganglionic neurons.  Neuroeffector junction Human Physiology Test 2 Three differences between Neuroeffector Junctions of the Autonomic Nervous System and the Neuromuscular Junctions of Somatic Nervous System.  In the ___, postsynaptic receptors are widely distributed on the target tissues and there is no specialized region of receptors analogous to the motor end plate of skeletal muscle.  autonomic nervous system Human Physiology Test 2 The overall function of the sympathetic nervous system is to ___. (think fight or flight). Includes increased arterial pressure, increased blood flow to active muscles, increased metabolic rate, increased blood glucose concentration, and increased mental activity and alertness.  mobilize the body for activity Human Physiology Test 2 The ___ nervous system operates continuously to modulate the functions of many organ systems such as heart, BV, GI, bronchi, and sweat glands. Sympathetic division of the autonomic Human Physiology Test 2 Preganglionic sympathetic neurons originate in nuclei of the __, leave the spinal cord via the ___ and ___, and project either to the paravertebral ganglia of the ___ or to a series of __.  thoracolumbar spinal cord, ventral motor roots, white rami, sympathetic chain, prevertebral ganglia Human Physiology Test 2 One category of preganglionic neuron synapse are on postganglionic neurons in ___ (superior cervical ganglia).  The other category of preganglionic neuron passes through the sympathetic chain without synapsing and continues on to synapse in ___ (celiac, superior mesenteric, and inferior mesenteric) that supply visceral organs, glands, and the enteric nervous system.  paravertebral ganglia of the sympathetic chain Prevertebral ganglia Human Physiology Test 2 This is a go between for the pre-ganglionic neurons of the spinal cord and some post ganglionic neurons of the sympathetic nervous system. Sympathetic chain ganglia Human Physiology Test 2 Preganglionic neurons found in the __, (Name main three plexus), synapse on postganglionic neurons which travel to the periphery and innervate the effector organs.  prevertebral ganglia, Superior mesenteric and inferior, Celiac Human Physiology Test 2 The preganglionic neurons of the sympathetic division arise from nuclei in the thoracic and lumbar spinal cord segments, specifically from the first thoracic segment to the third lumbar (T1-L3). Thus the sympathetic division is often called the ___.  Thoracolumbar Human Physiology Test 2 Sympathetic  pathways to organs in thorax (e.g. heart) have preganglionic neurons originating from the ___ Sympathetic pathways to organs in the pelvis (colon, genitals) have preganglionic neurons originating from the ___ Blood vessels, thermoregulatory sweat glands, and pilomotor muscle of the skin have preganglionic neurons that synapse on multiple ___, reflecting their broad distribution.  upper thoracic spinal cord lumbar spinal cord postganglionic neurons up and down the sympathetic chain Human Physiology Test 2 The ganglia of the sympathetic nervous system are found near the ___ Either in the: Paravertebral ganglia (__) or the ___ ganglia.  spinal cord, sympathetic chain, prevertebral Human Physiology Test 2 Ganglionic function The ___ ganglia projects to organs of the head, eyes and salivary glands (Part of Sympathetic chain) The ___ ganglia (plexus) projects to the stomach and small intestine The ___ ganglia (plexus) projects to the small and large intestine The ___ ganglia (plexus) projects to the lower large intestine, anus, bladder and genitals Superior cervical Celiac Superior Mesenteric Inferior Mesenteric Human Physiology Test 2 Ganglia are often incorporated into the wall of the target organ as a __. In a general sense, this is a network of branching interconnected fibers or vessels. Plexus Human Physiology Test 2 Because sympathetic ganglia are near the spine. Preganglionic neurons are ____ and Postganglionic neurons are __.  short, long Human Physiology Test 2 Preganglionic neurons of sympathetic division are always ___ and interact with their ___ receptors.  cholinergic, nicotinic Human Physiology Test 2 Postganglionic neurons of the sympathetic division are ___ in all divisions of the effector organs except in the thermoregulatory sweat glands where they are __. adrenergic, cholinergic Human Physiology Test 2 The effector organs that are innervated by sympathetic adrenergic neurons have one or more of the following types of receptors: ___ The thermoregulatory sweat glands innervated by sympathetic cholinergic neurons have ___ cholinoreceptors.  alpha 1, alpha 2, beta 1, beta2 Muscarinic Human Physiology Test 2 Sympathetic adrenergic varicosities contain... norepinephrine, ATP, and neuropeptide Y Human Physiology Test 2 When sympathetic postganglionic neurons adrenergic neurons are stimulated: 1. __ and __ are released together (they are colocalized in small dense core vesicles) with __first binding to purinergic receptors and causing a physiological effect (smooth muscle contraction). __ then binds to its receptor (alpha 1 in smooth muscle) which causes a second more prolonged contraction.  2. With more intense or higher-frequency stimuli, the large dense core vesicles release __, which binds to its receptors and initiates a third stage of long contractions.  ATP, and NEP ATP NEP Neuropeptide Y Human Physiology Test 2 The __ is a specialized ganglion in the sympathetic division of the autonomic nervous system. It is responsible for secreting catecholamines.  adrenal medulla Human Physiology Test 2 Preganglionic neurons innervating the adrenal medulla are found in the ___. The axons of these neurons travel in the greater splanchic nerve to the adrenal medulla, where they synapse on ___ cells and release ACh which activates nictotinic receptors.  Thoracic spinal cord, chromaffin Human Physiology Test 2 When their Nicontinic receptors are activated, the __ of the adrenal medulla secrete catecholamines. In contrast to sympathetic postganglionic neurons. These cells mainly secrete ___ and a small amount of NEP (80 to 20). The reason for this is the presence of __ which converts NEP to its counterpart.  chromaffin cells, epi, phenylethanolamine-N-methyltransferase (PNMT) Human Physiology Test 2 The function of PNMT is reliant on ___ from the adrenal cortex.  cortisol Human Physiology Test 2 A tumor of the adrenal medulla, or a ___, may be located on or near the adrenal medulla or at a distant (ectopic) location in the body. This cancer mainly secrets NEP becuase it doesn't have access to the ___ needed for PNMT to function.  Pheochromocytoma, Cortisol Human Physiology Test 2 The overall function of the parasympathetic division of the autonomic nervous system is __ and to __ energy. (rest and digest) restorative and conserve Human Physiology Test 2 Preganglionic neurons of the parasympathetic division have their cell bodies in the ___ or the ___. Their axons project out ganglia located near or in the effector organs.  brain stem (midbrain, pons, medulla) sacral spinal cord Human Physiology Test 2 Preganglionic neurons of the parasympthetic division arise from the nuclei of cranial nerves ___ or from sacral spinal cord segments ___ Therefore the parasympathetic division is called the ___ division.  3, 7, 9, 10 S2-4 Craniosacral Human Physiology Test 2 Cranial nerve __ is the occulomotor nerve. It has the biggest job of the nerves that control eye movement. It controls 4 of the 6 eye muscles in each eye: Medial rectus muscle (moves the eye inward toward the nose) Inferior rectus muscle (moves the eye down) III Human Physiology Test 2 Cranial nerve __, also called the facial nerve, carries the nerve fibers that control facial movement and expression. The facial nerve also carries nerves that are involved in taste to the anterior 2/3 of the tongue and producing tears (lacrimal gland). seven Human Physiology Test 2  Cranial Nerve __ (glossopharyngeal) provides motor, parasympathetic and sensory information to your mouth and throat. Among its many functions, this cranial nerve helps raise part of your throat, enabling swallowing. nine Human Physiology Test 2 Cranial nerve __, also known as the vagal nerves, are the main nerves of your parasympathetic nervous system. This system controls specific body functions such as your digestion, heart rate and immune system. These functions are involuntary, meaning you can't consciously control them. 10 Human Physiology Test 2 The ganglia of parasympathetic nervous system are located __.  near, on, or in the effector organs Human Physiology Test 2 Preganglionic neurons of the parasympathetic nervous system are ___ while postganglionic neurons are __.  long, short. Human Physiology Test 2 As in the sympathetic division, all preganglionic neurons are __ and release ACh which interacts with __ receptors on the cell bodies of postganglionic neurons.  These neurons are also cholinergic and release __ which interacts with ___ receptors on the effector organ.  Cholinergic, nicotinic ACh, Muscarinic Human Physiology Test 2 Parasympathetic postganglionic cholinergic nerves release their NT from varicosities onto their target tissues. The parasympathetic cholinergic varicosities release both the classic NT (__) and nonclass NT (__) The classic is synthesized in the varicosities from choline and acetyl CoA and are stored in ___.  A separate group of large dense-core vesicles contain ___ Lastly, the variscosities contain nitric oxide synthase and can synthesize __. ACh, VIP, NO Small Clear Vesicles VIP NO Human Physiology Test 2 When Parasympathetic postganglionic cholinergic neurons are stimulated ACh is released and binds to __ receptors on the tissue surface. This directs physiological action. With intense or high frequency stimulation, __ is released from large dense core vesicles which bind to receptors on the target tissue and augment the action of ACh. Muscarinic, VIP Human Physiology Test 2 Most organs have both sympathetic and parasympathetic innervation. These innervations operate __ or __. reciporically, synergistically Human Physiology Test 2 Smooth muscle walls of the bladder and GI have both __ which induces relaxation and __ which induces contraction. The sphincters of the bladder and GI have both __ which induces contraction and __ which induces relaxation. sympathetic innervation, parasympathetic innervation sympathetic innervation, parasympatheric innervation Human Physiology Test 2 In the male genitals __ innervation is responsible for ejaculation __ innervation is responsible for erection sympathetic parasympathetic Human Physiology Test 2 The __ nervous system stimulates aqueous saliva The __ nervous system stimulates enzymatic saliva parasympathetic, sympathetic Human Physiology Test 2 The __ is hearts internal pacemaker and it has both sympathetic and parasympathetic functions. It is able modulate heart rate by varying the amount of feedback between the two. Upping __ activity would up HR and upping __ activity would lower HR.  SA node Sympathetic Parasympathetic Human Physiology Test 2 The urinary bladder is another example of sympathetic and parasympathetic divisions working together. In adults __ or emptying of the bladder is under conscious control because the external sphincter is composed of skeletal muscle. However the __ reflex is controlled by the autonomic nervous system.  Microurition Human Physiology Test 2 When the bladder ___, sympathetic control dominates. It induces relaxation of the detrusor muscle via B2 receptors and contraction of the internal sphincter muscle via the a1 receptos, The external sphincter is voluntarily closed. With these muscles relaxed, the bladder can __.  is filling, fill Human Physiology Test 2 When the bladder ___, parasympathetic control dominates. This because fullnes is sensed by mechanorecptors in the bladder wall, and afferent neurons transmit this information to the spinal cord and then the brain stem. Parasympathetic control then causes the detrusor muscle to contract, the interior sphincter to relax, and the exterior sphincter must open voluntarily. Therefore microurition is controlled by __ action.  is full, parasympathetic Human Physiology Test 2 The __ of the pupil is reciprocally controlled by two muscles of the iris the __ and the __. size, pupillary dilator (radial), pupillary constrictor (sphincter) Human Physiology Test 2 The __ is controlled by sympathetic innervation through alpha1 receptors. Activation of these receptors causes a constriction of the radial muscle, which causes dilation of the pupil, or __.  pupillary dilator muscle, mydriasis Human Physiology Test 2 The __ is controlled by parasympathetic innervation through muscarinic receptors. Activation of these muscarinic receptors causes constriction of the sphincter muscle, which causes constriction of the pupil or __.  pupillary constrictor muscle, miosis Human Physiology Test 2 In the ___ light strikes the retina and parasympathetic nerves are activated in the Edinger-Westphal nucleus; activation of these fibers leads to contraction of the sphincter muscle and ___.  Pupillary light reflex, pupillary constriction Human Physiology Test 2 "In the ___, a blurred retinal image activates parasympathetic preganglionic neurons in the Edinger-Wesphal nucleus and leads to contraction of the sphincter muscle and ___. At the same time the __ contracts causing the lens to ""round up"" and its refractive power to increase. " accommodation response, pupillary constriction, ciliary muscle Human Physiology Test 2 There are some notable exceptions to the generalization of reciprocal innervation Several organs only have ____: these include sweat glands, vascular smooth muscle, and pilomotor muscles of the skin, adipose tissue, liver, and kidney.  sympathetic innervation.  Human Physiology Test 2 Generalizations about types of receptors and their mechanisms of action 1. In the ____, effector organs have muscarinic receptors. 2. In the ____, there are multiple receptor types including the four adrenoreceptors (a1,a2,b1,b2) and muscarinic (in tissues with sympathetic cholinergic innervation. 3. Among the sympathetic adrenoreceptors, receptor type is related to function.  __ receptors cause contraction of smooth muscle such as vascular smooth muscle, GI and Bladder Sphincters, pilomotor muscles, the radial muscle of the iris __ receptors are involved in metabolic functions such gluconeogenesis, lipolysis, renin secretion, and in all heart functions __ receptors cause relaxation of smooth muscle in bronchioles, wall of the bladder and GI 1. parasympathetic division 2. sympathetic division 3.  a1, B1, B2 Human Physiology Test 2 Autonomic receptors are coupled to GTP-binding proteins and are therefore called ___. They are composed of a single polypeptide chain that winds back and forth across the cell membrane seven times (seven pass membrane receptor proteins). The ligand binds to the extracellular domain.  G protein linked receptor Human Physiology Test 2 G proteins are ___. In other words they have three subunits  alpha, beta, and gamma. The __ subunit binds either GDP or GTP. __ means the protein is in the inactive state and __ means the protein is in the active state.  Heterotrimeric, alpha, GDP, GTP Human Physiology Test 2 __ are found in the vascular smooth muscle of the skin, skeletal muscle, and the splanchnic region, in the sphincters of the GI tract and bladder, and in the radial muscle of the iris. Activation of these recptors leads to contraction in each of these tissues. This involves a G protein called Gq and activation of ___.  alpha 1 receptors, phospholipase C Human Physiology Test 2 Steps of alpha1 receptor action 1. The alpha1 receptor is embedded in the cell membrane, where it is coupled, via the Gq protein to __. In the inactive state, the aq subunit of heterotrimeric Gq is bound to __.  2. Agonist binds to alpha 1, a ___ occurs in the alpha q subunit of the Gq. This results in two phenomena: ___ and ___.  3. The freed __ complex migrates within the cell membrane and binds to and activates ___. Intrinsic GTPase activity-->GTP back to GDP, and the alpha q goes back to the inactive state. 4. Activated phospholipase C catalyzes the liberation of __ and __ from phosphatidylinositol 4,5-diphosphate. The IP3 that is generated causes the release of __ from intracellular stores in the ER or SR, resulting in an increase in the intracellular concentration. Together Ca2+ and diacylglycerol activate protein kinase C which phosphorylates proteins. These excute final actions, such as muscle contraction. 1. Phospholipase C, GDP 2. conformational change, GDP is swapped for GTP on alpha q, alpha q detaches from the rest of Gq protein 3. alpha q GTP complex, Phospholipase C 4. Diacylglycerol, IP3, Ca2+ Human Physiology Test 2 __ are inhibitory and are located both pre and postsynaptically. They are less common than alpha 1 receptors. They are found on presynaptic adrenergic and cholinergic nerve terminals and in the GI tract. The are found in two forms __ and __.  Alpha 2, autoreceptors, and hetereceptors Human Physiology Test 2 Alpha2 receptors present on sympathetic postganglionic nerve terminals are called ___. In this function, activation of alpha2 receptors by NEP released from presynaptic terminals inhibits further release of NEP from the same terminals. This negative feedback conserves NEP in states of high stimulation of the sympathetic nervous system. The adrenal medulla does not have these, meaning that it can become depleted of catecholamines during periods of prolonged stress.  autoreceptors Human Physiology Test 2 Alpha2 receptors present on parasympathetic postganglionic nerve erminals of GI tract are called __. NEP is released from sympathetic postganglionic fibers that synapse on these parasympathetic postganglionic fibers. When activated by NEP, the alpha2 receptors cause inhibition of ACh from the parasympathetic postganglionic nerve terminals. In this way, the sympathetic nervous system indirectly inhibits GI function. Heteroreceptors Human Physiology Test 2 Heteroreceptor mechanism of action involve the inhibition of __ described in the following steps.  1. The agonist (NEP) binds to the alpha2 receptor, which is coupled to __ by an inhibitory G protein (Gi) 2. When NEP is bound, the Gi protein ___ , and the ai subunit dissociates from the G protein complex.  3. The ai subunit then migrates in the membrane and binds to and ___. As a result cAMP levels decrease, producing the final physiologic reaction.  adenylyl cyclase 1. adenylyl cyclase 2. releases GDP and binds GTP 3. inhibits adenylyl cyclase Human Physiology Test 2 __ receptors are prominent in the heart. They are present in the SA node, in AV node, and in the ventricular muscle, Activation of this leads to increased heart rate in SA node, increased conduction velocity in AV node, and increased contractility in ventricular muscle respectively.  B1  Human Physiology Test 2 The mechanism of B1 receptors involves the activation of __. adenylyl cyclase Human Physiology Test 2 Activation of B1 receptors  1. B1 receptors are embedded in the cell membrane inactive state, They are coupled to a Gs protein, to ___. In the inactive state, the alpha s subunit of the Gs protein is bound to __.  2. When an agonist binds, GDP is swapped for __ and the alpha s subunit detaches.  3. The alpha s-GTP complex migrates within the cells activates __. GTP is converted back to GDP and the alpha-s complex comes turns back into its inactive state.  4. Activated adenylyl cyclase catalyzes the conversion of ATP to ___, which serves as the second messenger. This activates protein kinases, which phosphorylates proteins, initiates the final physiological change.  1. adenylyl cyclase, GDP 2. GTP 3. adenylyl cyclase 4. cAMP,  Human Physiology Test 2 __ are found in the vascular smooth muscle of skeletal muscle, in the walls of the GI tract and bladder and in the bronchioles. The activation these receptors leads to relaxation or dilation.  B2 receptors Human Physiology Test 2 NEP and EP have equal potencies at __ receptors and need high amounts of catacholamine release in order to trigger (Nerve secretion not from the adrenal medulla) NEP and EP have equal potencies at __ receptors and low amounts of catacholamine release in order to triger (Nerves and Adrenal Medulla will trigger) __ receptors are preferentially activated by epinephrine, thus it is preferentially activated by the adrenal medulla.  a1, a2 B1 B2 Human Physiology Test 2 __ receptors are found in several important locations: motor end plates of skeletal muscle, on all postganglionic nurons of both sympathatic and parasympathetic nervous systems, and on the chromaffin cells of the adrenal medulla. ACh is its natural agonist.  Nicotinic Human Physiology Test 2 The nicontinic receptors at the motor end plate and in ganglia are similar but not the same with MEP being symbolized by __ and the ganglionic receptors being symbolized by __.  Nm, Nn Human Physiology Test 2 Nicotinic receptors have __ subunits. They are labeled as __. The ACh binds to the __ subunit. When it binds the receptors open and allows K and Na to flow down their gradients and depolarize.  alpha, alpha, gamma, delta, and beta, alpha Human Physiology Test 2 __ are located in all of the effector organs of the parasympathetic nervous system: in the heart, GI, bronchioles, ladder and male sex organs. These receptors are also found in certain effector organs of the sympathetic nervous system (sweat glands).  Muscarinic receptors Human Physiology Test 2 Some muscarinic receptors (M1, M3, and M5) have the same mechanism of action as ___. In these cases binding of the agonist (ACH) causes the dissociation of the alpha subunit of the G protein, activation of Phospholipase C, and generation of IP3 and diacylglycerol. IP3 releases Ca2+ and increases Ca2+ and diacylglycerol produces the tissue specific reactions.  adrenoreceptors Human Physiology Test 2 Other muscarinic receptors __ act by inhibiting adenylyl cyclases and decreasing intracellular cAMP.  (M4) Human Physiology Test 2 Some muscarinic receptors (M2) alter physiological processes via ___. In these cases no other second messenger is involved. For example, muscarinic receptors in the cardiac SA node, when activated by ACh, produce activation of Gi protein and release of the ai subunit, which binds directly to K+ channels. These channels open, slowing the rate of depolarization of SA node and decresing heart rate.  direct action of the G protein Human Physiology Test 2 What is the Goldman-Hodgekin-Katz Equation src=""paste-78bdead7e5711ef134f6f29c56787168678f56d9.jpg"">" "<img Human Physiology Test 2 What is the Chord Conductance Equation? "<img src=""pastefdf3c0122f63ae152ec019d6792873c16eb15425.jpg""> Where Vm is membrane potential in volts G is conductance in siemens Vk, VNa, VCl are the equilibrium potentials for these ions" Human Physiology Test 2 The ___ is a group of nucleii in the brain that is responsible for temperature regulation, thirst, and food intake Hypothalamus Human Physiology Test 2 midbrain Human Physiology Test 2 The __ is resposible for the Micturition center.  The __ is the pneumotaxic center pons Human Physiology Test 2 The ___ is where the DRG, VRG, Vasomotor center, swallowing, coughing and vomiting centers are located.  Medulla

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