Intro To Physiology
Nervous System

Master regulator for the body

Takes sensory input, integrates it, and elicits motor output

Two divisions o CNS
 Consists of the brain and the spinal cord
 Mostly responsible for integration o PNS
 Spinal nerves
 Afferent/Sensory

Towards the CNS

Sensory input from sensory receptors

Enters the dorsal side of the spinal cord

No synapses- cell bodies exist in a dorsal root ganglion
 Efferent/Motor

Away from the CNS to effectors

Effectors are muscles and glands

Two divisions o ANS (Autonomic NS)
 Involuntary
 Visceral motor control of glands and smooth muscle
 Two divisions

Sympathetic-fight or flight o Synapses right outside the spinal cord in sympathetic trunks o Uses ACH in the first path, Epi or Norepi in the second path

Parasympathetic-rest and digest o Synapses close to the effector organ o Uses ACH for both paths

Both divisions have their first path myelinated while the second path is unmyelinated o Somatic NS
 Voluntary motor control
 From the CNS to skeletal muscles
 Single neuron all myelinated
 Uses ACH as the neurotransmitter

Glial cells-non neuronal cells in the nervous system o Many more glial cells than neurons

o Insulation (myelin)
 Oligodendrocytes in the CNS

Can wrap more than 1 neuron
 Schwann Cells in the PNS

Can only wrap 1 o Protection
 Astrocytes

The majority of glial cells

Provide nourishment to the cells

Create the Blood Brain Barrier o Circulation
 Ependymal cells

Ciliated

Circulate (do not produce) CSF o CSF is produced by a choroid plexus o Immunity
 Microglia

Macrophages
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Immune system isn’t allowed into nervous system

Neuron o Dendrites
 The receptive region of the neuron
 Contains Na and K ion channels to start depolarization
 Receives neurotransmitter via receptors
 Post synapse

The signal goes electrical, chemical, electrical o Membrane potential
 Resting cells are at -70 mv
 Action potential brings them to +30
 Opening of Na channels brings + charges into the cell

Causes the climb in charge

Depolarization
 Repolarization is caused by the delayed opening of the K gated ion channel
(activated at the same time but delayed) allowing K ions out of the cell
 Also slow to close, causing hyperpolarization

This has the added benefit of making sure the neuron cant fire too much too fast
 Na/K pump restores ion concentrations after
 The anions in the cell are mostly responsible for the negative charge
 Charges balance out


An electrical equilibrium is created based on the regular charge of the cell, or based on an outside charge (experimentally)

Charges flow to make the charges equal

Add + charge to cell, it wants to decrease the potential so it flows out

Add – charge to cell, it wants to increase the potential so ions flow in
 Threshold potential of the neuron is reached at -55 mv

Reached at the axon hillock
 -58 mv is the K ion potential equilibrium o Graded potentials
 Depolarizes one region of the cell
 Can be any level

-34

-24

-85 (so it can even be hyperpolarization)

Etc
 The cell region is depolarized yet does not reach threshold at -55 mv
 Graded potentials can lead to Action potentials
 Can be summed in time or in space

Temporal summation o One after another, they add up

Spatial summation o In the same space, add together o Action potential
 Reaches threshold
 Generated at the axon hillock
 Depolarization due to Na channels opening
 Reaches about +30
 Then K ion channels open up and there is repolarization
 Then hyperpolarization as they are slow to shut
 Then the gradient is reestablished by the Na/K pump
 Another one cannot be fired for 4-5 ms
 Needs to be strong to overcome hyperpolarization

Absolute refractory- nothing can be fired

Relative refractory-only a very strong graded potential will lead to an AP
 The number of AP’s determines the stimulus strength o Variables
 Size

Increase diameter, the speed increases
 Myelination

Myelination increases speed by a lot

Saltatory conduction

o In jumps only to the nodes of ranvier o Makes it so that only at the nodes of ranvier does the AP have to occur o Three types of neurons
 Multipolar

Most common
 Bipolar

Found only in special senses
 Unipolar

Sensory receptors o Three functions
 Sensory (afferent)
 Motor (efferent)
 Interneurons

CNS

Most common (99%)

Neurotransmitters o Diffuse from high to low gradient across the synaptic cleft o IPSP
 Inhibitory
 Hyperpolarizes
 EX: Cl- or GABA o EPSP
 Excitatory
 Depolarizes
 EX: glutamate o EPSP and IPSP can fight each other to try and create (or not create) an AP o The distance from the axon hillock makes a difference, as the depolarization decreases as the distance increases

Terminal bulbs o Ca ion channels (voltage gated) open when the AP reaches, and the influx of Ca pushes vesicles containing NTs to the wall of the terminal bulb o This causes their release into the synapse

Ionotropic receptors o Everything discussed here o Fast

Metabotropic receptors o Use second messengers o Usually G-protein linked o And takes longer due to the second messengers

Endocrine System




Method of communication in the body o Use the blood stream o Hormones are long distance
Hypothalamus- top of the pituitary gland- master control
Pituitary-second in command
Lipid soluble hormones can go directly through the bilayer and attach to a receptor inside the cell

Hormones are usually controlled by metabotropic receptors o Their effect takes longer than neurotransmitters
 Due to amplification

Target cell activation depends on 3 factors o Number of hormones in the blood o Number of receptors o Affinity for receptors (how tightly they bind)
 cAMP second messenger o G s
on a G-protein receptor o Response is amplified o Activates PKA o Hormones that use this cAMP
 Cattecholamines
 Acth
 FSH
 LH
 Glucagon
 PTH
 TSH
 Calcitonin

Pip second messenger o DAG and IP3 activated Calcium ion release and therefore PKC o Hormones
 Catecholamines
 TRH
 ADH
 GnRH
 Ocytocin o G q
subuinits

Hormone interactions o Antagonism o Permissiveness o Synergism


Endocrine gland stimulations o Humoral (nutrients in blood) o Hormones o Neuronal
 Faster than hormonal

Pituitary gland portal system o Regular portal system is arteriole-capillary-venule o Pituitary portal system is capillary-vein-capillary
 Goes quickly from hypothalamus to pituitary
 More concentrated hormones in a shorter distance

Speed and concentration

Pituitary o Posterior pituitary
 Oxytocin

Made in the paraventricular nuclei of the hypothalamus and sent to the posterior pituitary to be released
 ADH

Supraoptic nuclei in the hypothalamus make it o Anterior pituitary
 TSH, GH, ACTH, prolactin, LH, FSH

Aneurysm o Saccular-bulb at risk of rupturing o Fusiform-not as dangerous-> longer elongation o Ruptured-broken open

Kidneys o Adh production
 Mechanism?

Triggers kidneys to reabsorb water, therefore increasing blood volume and pressure

Based on osmolality

Thyroid hormone o Major metabolic hormone o T3 and T4 (needs IODINE) o Path
 Hypothalamus-TSH (ant pituitary)-thyroid-thyroid hormones

PTH vs Calcitonin o PTH increases the blood Ca level and breaks the bone down o Calcitonin decreases blood Ca level by building the bone up

Insulin vs Glucagon o Insulin decreases blood glucose level o Glucagon increases glucose level


Aldosterone o Directly brings in Na and water into the blood in the kidneys o Controlled
 Increased K+ level in blood
 Decreased blood volume or blood pressure
 Acth released by anterior pituitary
 Increased blood pressure or volume

Inhibitory o Targets kidney tubules o Antagonized by ANP release by the heart

Stress response o CRH released by hypothalamus (corticotropin releasing hormone) o Causes the adrenal medulla to release catecholamines (epi/norepi) o Catecholamines release ACTH to raise the blood pressure o Catecholamines short term stress response o Mineralo and glucocorticoids=long term stress response

Different behavior? o Due to different receptors
Muscles

Smooth, cardiac, and skeletal

Skeletal is under conscious control

Smooth and cardiac are unconscious

Four functional characteristics of muscle tissue o Contraction o Extension o Elastic o Excitability

Skeletal o Striated o Multinucleated o Cylindrical o ACH binds to it and is always excitatory

Cardiac o Striated o Multibranched o Pacemaker o Cells connected by calated discs

Smooth o No striations o Spindle shaped

o Shortens with calmodulin

Skeletal muscles o Contract small to large o Smaller motor units first

Each bundle separated by perimysium o Bundle=fascicle

Muscle fiber (cell) o Surrounded by the endomysium

Myofibrils o Contains two filaments (myofilaments)
 Actin and myosin

Each muscle fiber contains many myofibrils

Motor unit o The motor neuron and all of the muscle fibers it innervates o Vary in size

Myosin and actin o Work together to contract the muscle

T tubules o Allow the AP to go down into cell and release Ca from the sarcoplasmic reticulum

Sarcoplasmic reticulum o Calcium ion storage

Glycosomes o Storage of glycogen for quick energy

Sarcomere o The smallest unit of the muscle o Z disc to z disc o H zone is based on thick filaments only o I bands only thin o A band length of myosin

Calcium o The final trigger for the muscle contraction, what is the initial trigger for the muscle cell

Muscle contraction steps o Na enters and AP propagated along the cell and down the t tubule o AP triggers Ca channel in the SR to open o Ca binds to troponin
 Changes the shape of tropomyosin and actin active sites are exposed o Contraction
 Myosin heads bind to active sites on actin and use energy by ATP to push o Removal of calcium from the cytosol o Tropomyosin blockage restored

Thin filaments

o Actin o Two actin molecules helix shape o Actin associated with troponin and tropomyosin o Troponin binds to Ca ions o Tropomyosin covers active sites

Myosin o Thick filaments o 2 lobed heads

Cross bridge o Myosin head attaches and forms a cross bridge o ATP is released to push the cross bridge
 Power stroke o ATP attaches to dislodge crossbridge o The ATP to ADP charges it for its next powerstroke

Sliding filament theory o Myosin pulls actin closer o The H band gets smaller

Rigor mortis o Crossbridge remain engaged after death
 High tension o Muscles need ATP to relax

Motor unit recruitment and wave summation o Increasely strong muscle contractions o Motor unit recruitment recruits more motor units o Wave summation work for one motor unit increasing in force (not calling more)

Size principle for motor units o Small-meduim-large

Muscle contaction o Isometric
 Same length
 No shortening of the sarcomere
 Develop tension in the muscle o Isotonic
 Shortening
 Same tension
 Tension is at or above the load so the muscle shortens

Energy o Creatine phosphate
 Directly converts ADP to ATP for quick energy o Anaerobic mechanism
 Hlycolysis and lactic acid forms

o Aerobic mechanism
 Glucose and fatty acids from fat tissue
 Provides hours of energy

3 types of fibers o Slow oxidative
 Endurance activities
 First recruited o Fast oxidative
 Sprinting/walking o Fast glycolytic
 Short term intense movement

Oxygen debt o Spend more energy than can be provided o Lactic acid build up needs to be corrected
Blood Vessels

Deoxygenated blood comes from a capillary into the right atrium from the vena cava

Pulmonary circuit is lower pressure

Systemic circuit is high pressure

Arterioles go away from the heart

Veins go towards the heart

Pulmonary veins-left atrium-left ventricle-aorta-arterioles-capillary-venules-veins-vena cavaright atrium-right ventricle-pulmonary arteries

Cardiac output o HR X (EDV-ESV) o EDV- amount of blood left in ventricle when the heart is relaxed o ESV- amount of blood left in ventricle during contraction

The highest pressure of anywhere in the circulatory system is in the left ventricle (to get it into the aorta)

Average of 5.25L of blood per minute

Preload o Greater preload leads to a higher stroke volume o Unless they are too high, which decreases stroke volume
 Stretches the sarcomere too much

Contractility o The contractile force of the heart o Increased by the amount of Ca ions released
 More calcium, more crossbridges

Afterload o The amount left over o Greater left over, need more pressure to push the blood out


Sympathetic nervous system increases the heart rate

Parasymp decreases the heart rate

ADH and aldosterone can affect the volume of the blood

CHF caused by MI, high Bp, etc o Pulmonary CHF
 Left side fails first and the blood backs up in the lungs o Peripheral CHF
 Right side fails first and the blood pools in extremities

Norepi or epi o Released in adrenal medulla o Activate cAMP mechanisms o Allows more Ca into the cell and cause a stronger contraction

Vessels o Capillaries are responsible for a gas exchange o Types
 Fenestrated

Holes in the walls (window)

Intestines

Filtration or absorption is their function

SI is the site of most absorption

Endocrine glands also use fenestrated capillaries
 Continuous

No holes/spaces

Lungs-gasses are small enough you just need PM

Specialized continuous capillaries are in the brain
 Sinusoidal

Allows cells to go through

WBC’s move around

Arteries o Elastic-conducting o Muscular-distributing o More elastic tissue
 Withstand higher pressure o Thicker tunica media

Veins o Valves o Lower pressure

Capillary beds o Perfusion depends on the sphincter of arteriole o Can control which capillary beds are open or closed at a time

Mean arteriole pressure pushes blood through the heart

o Diastolic pressure + 1/3 (pulse pressure (difference between systole and diastole)) o

Pressure through blood vessels is steady-does not vary up and down

How do the veins return blood to the heart o Skeletal muscle contractions o Breathing o Valves in the veins preventing backflow

Contractility is defined by a sarcomere length o At a stable sarcomere length still get increased contraction due to higher calcium levels

Kidney compensation o Multiple ways the kidneys can affect BP o Renin Angiotensin aldosterone system
 Angiotensin II causes an increase in BP
 Constricts blood vessels by impairing NO synthesis o Increases aldosterone production
 Retains Na and water increasing blood volume and blood pressure

Intrinsic mechanisms o Local o Distribute blood flow to individual organs as needed o Metabolic controls and myogenic controls

Extrinsic mechanisms o Global o Nerves and hormones o Control levels all over the body, not just to specific places

Factors determine fluid in and out

o Hydrostatic pressure-force fluid out o Osmotic pressure-water moving in o Net filtration pressure
Respiratory System

4 processes of respiration o Inspiration o Expiration o External respiration o Internal respiration

Continuous capillaries

Breathing o Air passes to alveoli where gas exchange occurs o Inspiration
 O
2
into the body o Exhalation
 CO2 out

Conducting zone o Filter and warm (nasal cavity) o Moisten the air o Rigid tube with cartilage o Cilia/structures that help filter

Bronchi split until they reach the terminal bronchioles

Alveoli pop up in the respiratory bronchioles

Dividing line is between the terminal bronchioles and respiratory bronchioles

Respiratory zone o Less rigid o Some smooth muscle o Smooth muscle wrapped around the respiratory bronchioles

What controls the dilation of the airway o Smooth muscle controlled by
 Gas
 Sympathetic

Dilates!!!!!!!!!
 α receptors constrict (found in the vessels)
 β receptors dilate (found in the lungs)
 also found in coronary arteries and skeletal muscle arteries
 external respiration membrane o 3 or 4 structures o Alveoli o Continuous capillaries

o 2 types of cells that make up an alveolus
 Type 1-shared respiratory membrane
 Type 2-surfacant secreting

Detergent that breaks surface tension
 Basement membrane (fused) o Immune cells in our lungs
 Macrophages constantly hunt for bacteria and pathogens
 Macrophage is stuck in alveoli

Negative pressure breathing o Generate a negative pressure to pull air in o Inhalation is active
 Contract the muscles o Exhalation is passive
 Relax muscles and push air out o Breathing muscles
 Diaphragm and intercostal muscles

Lungs automatically want to collapse, chest pushing out

Creates an interplural pressure that is always negative relative to the atmospheric pressure

Visceral pleura lines lungs

Parietal pleura lines the inside of the chest wall

Relative to ATM o Interpulmonary pressure negative on inspiration, zero at break, and positive on expiration

Transpulmonary pressure at 0? o Pneumothorax

P p
=P
T
X C o Partial pressure= total pressure X concentration

Gasses diffuse from high to low o Tissues are in need of oxygen, oxygen diffuses into them

Dead air space o Mixes oxygen o 150 mL o Conducting structures

Dead air space causes expired O2 to be higher than alveolar O2 o The alveolar oxygen is low due to it perfusing into the capillaries

High altitude o Breathing rate increases o More Red Blood cell production

Respiratory groups o Ventral respiratory group
 Generate normal breathing

 GABA o Dorsal Respiratory Group
 Modulates the VRG
 Can sense changes in parameters, to then effect o Pontine respiratory center
 Can change rate

Respiratory stimulant o CO2 levels drive breathing o CO2 produced from tissues o Decreases the PH of the blood by being converted to carbonic acid which lowers the PH

Hyperventilation o Usually a V/Q match o Ventilation o Perfusion o Need to match

Oxygen carried in the blood by hemoglobin (Hb)

90% of Oxygen attached to Hb o Gives it more solubility o 4 bonds pere Heme

The affinity of hemoglobin for oxygen changes with the extent of oxygen saturation

More oxygen there is, the more affinity there is for O2

High levels of O2 sat o Usually unladed fast to the tissues, and difficult to load to the Hb

Decreased CO2 pressure leads it to be harder to unload

Increased CO2 pressure? Easier to unload

Lower body temperature triggers decreased co2 levels

High metabolic activity leads to increased CO2

CO2 o Typically carried in the blood o Bicarbonate ion o 70% is bicarbonate ion o 20% is dissolved directly in the plasma o 10% bound to Hb

Carbonic anhydrase o Converts CO2 to carbonic acid o In the Red Blood Cell

Cl- comes into the RBC as the HCO3- ion leaves to balance the charges

Haldane effect o Lower O2 levels?
 Higher PCO2 o Higher O2 levels?

 Lower PCO2

If oxygen is saturated, harder for CO2 to bind to Hb

BPG o Helps push O2 off of the Hb so high levels in systemic capillaries causes O2 unloading

HAPE o High altitude pulmonary edema o Fluid in the lungs o Causes a decrease in alveolar ventilation
Digestive system

Nutrient competition in the gut between good and bad bacteria

Leptin is made by bacteria and signals body to feed

Many organs have dual functions o Liver o Pancreas o Pharynx

Accessory organs o Support the digestive system (not a part of the alimentary canal) o The alimentary canal is the path from the mouth to the anus
 The “tube within the tube” o Pancreas o Gallbladder o Liver o Stomach cells

Mechanical digestion o Occurs via the teeth

Chemical digestion o Chemically breaks down food o First is salivary amylase
 Breaks down carbohydrates o HCl degrades food in the stomach
 Creates chime
 Acid also kills many bacteria o SI
 Major place of chemical digestion
 Proteins, fats, carbs are all degraded and absorbed

Gallbladder o Stores concentrated bile from the liver o Shunts it to the small intestine via the common bile duct (with the pancreas)

Large intestine o Major site of water reabsorption

o Also produces the feces

The goal of digestion is to get the components of food broken down into usable parts

Long reflexes o Go all the way to the CNS and get integrated o Prepare the body to receive food

Short reflexes o Local (enteric) nerve plexus

Reflexes are stimulated by food

Antacids work by blocking H+ ion production and making the stomach acid less acidic o Has the effect of not killing some of the bacteria o Acid is usually 2-3 pH

Stomach digestion o Breaks down food mechanically and chemically
 Mechanical is churning
 Chemical is acid and peptidases o Gastrin
 Stimulates the secretion of HCl and pepsinogen which works to chemically digest proteins (in its active pepsin form) o Pepsinogen
 Activated by HCl
 Into pepsin
 Pepsin then works to break down proteins o Parietal cells
 Make the HCl
 Secreted by goblet cells o Chief cells
 Make the pepsinogen o Enteroendocrine cells
 Hormone producing cells

How does the brain control gastric juice production o Brain senses food and secretes additional gastric juice
 Reflect of food…saliva o Symp-less o Parasymp-more o Ph based
 Low pH-less gastric juice

Vagus nerve of the parasymp NS stimulates the digestive system

Which 3 chemicals are necessary for maximum HCl production? o Gastrin o ACH
 From the parasymp (vagus)

o Histamine

Chyme gets sent to the duodenum o The duodenum produces many hormones
 Secretin
 CCK (Cholecystokinin)
 VIP (vasoactive intestinal peptide) o All of these hormones are known under the collective name enterogastrones

SI o Nutrient absorption
 Microvilli
 Folds (gyri)
 Increased surface area o Microvilli contain brush border enzyme
 Bring things to the monomer form

Nutrients absorbed go to the liver o Hepatic portal system o Liver creates bile o Bile salts
 Emulsifiers

Help break down fats o Lacteals take the fats to the liver
 Triglycerides pass into lacteals
 Called chylomicrons

Liver o Processes SI blood o Liver stores the glycogen o Detoxifies compounds o Arterioles and venules send blood the same way
 Arterioles supply oxygen
 Venules supply nutriets

 o Kupffer cells
 WBC (macrophages) o Liver can regenerate o Bile production
 CCK-singals the gallbladder to release
 Secretin

Tells the liver to make bile

H+ is neutralized in the SI by bicarbonate ion o Comes from the pancreatic juice
CCK induces the pancreas to produce pancreatic juice
Secretin binds and causes copious release of bicarbonate ions in pancreatic juice


Pancreas hormones (in juice) o Trypsinogen  trypsin o Chemotrypsinogen  chemotrypsin o Procarboxypeptidase  carboxypeptidase o Activated by brush boarder enzymes

Large intestine o Water reabsorption o Some absorption of ions occurs with the water o A lot of bacteria in the LI, some good others bad
Immune System

Adaptive vs innate immune system o Innate
 First line of defense

Skin barrier

Mucus membranes

Skin secretions
 Doesn’t require previous exposure
 Present at birth
 Enzymes that can directly kill bacteria
 Faster and more immediate
 Has internal nonspecific defenses

Phagocytes

Fever

Natural killer cells

Antimicrobial proteins

Inflammation
 NK cells recognize antigen (just that it has an antigen) and releases chemicals called granzymes to perforate the membrane
 Macrophages

Derived from monocytes

Stem cell is the hemocytoblast

General macrophages eat bacteria

Search for food and engulf them through a process known as phagocytosis

Arrive after neutrophils (part of innate defense)
 Phagocytosis

Success rate increased (opsonization)

Antibodies specific to the antigen are produces and coat the bacteria o Neutralization o Agglutination



 o Precipitation

Inflammatory response o Neutrophils enter blood from the bone marrow o Margination
 They stick to the sides of the blood vessel wall via CAM (cell adhesion molecules) o Diapediesis
 Walk to the site o Positive chemotaxis
 Call more WBC o Four cardinal signs
 Swelling

Edema
 Heat

Increased blood flow
 Pain

Leaked protein rich fluid

Histamine released
 Redness

Increased blood flow
Increased temperature short term helps fight the infection
Long term fever can be dangerous for the organism
Interferons and complement proteins enhance the innate defenses by attacking microbes directly o Interferons are local o Complement proteins are more whole body

Adative immune system o Specific o Made to attack very specific microbes o Vascular o Antibodies o Lymphocytes vs leukeocytes
 Lymphocyte is one of three specific types of WBC
 Leukeocytes are WBC overall (larger category) o Immunocompetance (need to get educated)
 Happens in the T gland for T cells
 Bone marrow for B cells
 Have not been exposed to antigen? Naïve o APC (antigen presenting cells)
 Big 3?

Dendritic cells


B cells

Macrophages o T cells
 Recognize our own MHC proteins
 If they recognize it? They are killed off to avoid an autoimmune reaction
 Surviving cells are self tolerant o Activated immune cells are “selected” and begin to divide o B cells
 Plasma B cells-antibody secreted
 Memory B cells-stay around for next reaction for less of a lag time o Humoral immunity-antibody mediated (B-cell)
 Active-make antibodies

Natural-antibodies/reaction

Artificial-vaccine
 Passive-pass antibodies

Natural-passed from mom

Artificial-serum (antibodies) o Cell mediated immunity
 T cell response

Helper T cells recognize and help mount an attack o CD4 o Respond to class II MHC’s via the APC’s

Cytotoxic T cells kill directly o Induce apoptosis with granzymes and perforin o CD8 o Respond directly to class I MHC proteins
 MHCII

Only present in APC

Taken in by APC cells (endocytosed) and combined with a MHCII receptor

Only an antigen fragment is displayed (antigenic determinant)
 MHCI

All cells carry it

Display any antigens that invade the cell
Urinary System

Kidney is at the center of the urinary system o Major functions
 Filter blood
 Excrete urine
 pH balance is important

o blood comes from the aorta and feeds the kidneys o pair of ureters collects the urine
 nephrons-functional unit of the kidney o also the urine forming units

Proximal convoluted tubule (PCT) o Cells have lots of mitochondria and microvilli
 Absorption function

Kidneys modulate the systemic BP o Catcholamines o Angiotensin o Renin o ADH

Glomerulus is where renin is released o Can sense the BP o Renin raises the BP (vasoconstrict)

Proteins cannot pass throught he glomerular filtration membrane because it is too selective
 three forces determine the filtrate formation o glomerular hydrostatic pressure
 out o osmotic pressure
 in o capsular hydrostatic pressure
 in o net outward pressure is 10mm hg
 three mechanisms help maintain glomerular filtration rate when systemic bp is altered o myogenic o tubuloglomerular o hormonal
 afferent arterioles enter the glomerular capsul
 efferent arterioles leave
 the macula densa cells in the ascending loop of henle sense alteration of the filtrate flow and the NaCl concentration

The water in kidneys follows solutes out passively

Proximal Convoluted Tubule o Contains the Na/K pump that establishes the gradient to maintain ion balance

Primary and secondary active transport for absorption

Transport maximum exists for everything but Na ion o Maximum number of carriers are operating

DCT o Primary control of tubular secretion/reabsorption
 Sends things back IN to the Tube if there is too much in the blood

o Aldosterone-sends Na in o Parathyroid hormone (PTH)-sends Ca in

Loop of henle o Descending limb-water reabsorption passive o Ascending limb-solute reabsorption (mostly active)

Collecting duct o Water reuptake
 Concentrates the urine o ADH affects it
 Higher levels, more aquaporins, more water reabsorption o Water is reabsorbed into the vasa recta as to not affect the ion concentrations
Reproduction

Meiosis evolved o Mechanism to correct for error without cell division o Ploidy cycle-sometimes benefit from being haploid

Genes required for mitosis were repurposed for meiosis

Sex started-evolution occurred rapidly

Meiosis o Two stages
 Meiosis I-hapliod but still replicated
 Meiosis II-haploid and only one copy o Genetic variability
 Random assortment in metaphase I
 Crossing over in prophase I
 Random fertilization o 4 gametes out of the male process o 1 viable gamete for females (3 polar bodies)

Male gametes made in the seminiferous tubules o Edge cells move towards the lumen and become sperm

Spermatogonia o The male stem cells o Type A and B daughter cells

Sustentacular cells (sertoli cells) o Surround and protect the spermatogonia o Keep the immune system out
 Tight junctions o Produce ABP (andreogen binding proteins)
 Respond to FSH and LH o APB and testosterone combine to form the complex needed to form mature sperm

FSH and LH

o Stimulated by GnRH

Females o Meiosis produces polar bodies
 These polar bodies are not viable gametes
 Nonfunctional o 1 function oocyte is produced o a woman has 2 million primary oocytes present at birth o only 10% make it to primary follicle stage o Always more than one oocyte going through stages
 Only one responds best to the hormones o Follicular phase and luteal phase
 Follicular phase

Initial follicle to the thick follicle

Primary to secondary oocyte

14 days average
 Lueteal phase

Almost always 14 days

Antrum, secondary oocyte, and its release o Thecal cells
 Release male hormones (androgens) o Granulosa cells
 Convert androgens to estrogens o Sometimes more than one oocyte is released
 Fertilized by 2 different sperm?

Fraternal twins o Fertilized
 Once it is fertilized, the blastocyst is implanted into the uterine wall to allow it to grow o Sperm cell is only good for 1-2 days because the mitochondria die out and use up all the energy o 3-4 days for an oocyte
 Has all of the cytoplasm and organelles needed to survive o Increasing LH/FSH surge
 Induces the follicle growth o LH
 Receptors on the thecal cells create androgens o FSH
 Receptors on the follicle cells o Estrogen release in the blood causes a burst of FSH/LH release (not production)
 Positive feedback mechanism o Follicle gets larger, produces more estrogen, this triggers a shut off

o FSH and LH surge occurs around 14 days
 Estrogen dependent o Surge causes ovulation o After ovulation, the follicle ruptures and this leads to declining estrogen levels in the blood o Estrogen levels decrease, progesterone increases o Follicular cells become the corpus luteum
 Under control of LH
 Degraded if no fertilization o Estrogen and progesterone
 Estrogen=ovulation

Also allows sperm into the uterus by making the mucus slimy
 Progesterone=changing in the uterus to prepare for ovulation

Blocks the uterus again o No fertilization?
 The uterine lining is shed o Regular bleeding and shedding (monthly)
 The purpose is to make sure the uterine wall is responding to the hormones
 Also helps disinfect the uterus o Uterine cycle
 Menstrual phase (shed lining)
 Proliferative phase (builds up)
 Secretory phase (postovulatory)

The endometrium prepares for the implantation of the embryo o Implantation occurs
 Now the uterus needs to keep the nutrients up o Inner cell mass develops into the blastocyte o The lungs of the baby develop last o Human chorionic gonadotropic (HCG)
 Spike helps initially develop the placenta
 Develops the corpus luteum

That secretes estrogen and progesterone o Hormones from the corpus luteum maintain the uterus structure o The HCG comes from the oocyte itself if fertilized o HCG drops off?
 This leads to estrogen and progesterone getting released from the placenta

This occurs after the embryo is implanted o Fetus is not rejected by the mother because the mother recognizes it