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What is a NEURON?

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A neuron is a nerve cell that is the basic building block of the nervous system.
 highly specialized nerve cells are responsible for communicating information in both chemical and electrical forms.

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How many parts does a neuron have?

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What are the 3 parts of a NEURON ?

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What does an AXON DO?

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Carries messages.
A tube like structure

 What is the function of dendrites and Axons?

The difference between Dendrites and
Axons Of a Neuron are?
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Axons
Take information away from the cell body
Smooth Surface
Generally only 1 axon per cell
No ribosomes
Can have myelin
Branch further from the cell body
Dendrites
Bring information to the cell body
Rough Surface (dendritic spines)
Usually many dendrites per cell
Have ribosomes
No myelin insulation
Branch near the cell body

What is the resting potential?

 When a neuron is NOT sending a signal it is at
“REST.”
 When at rest the inside of the neuron is – neg charged.
 At rest potassium K+ can cross through the membrane easily.
 At rest (CL-) chloride and sodium (NA+) have a more difficult time passing. At rest there are more?
 sodium ions on the outside of the neuron and less potassium on the inside.

 What Is Action Potential?
 Also know as a Nerve impulse.

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Action potential occurs when a neuron send information down an axon, from the CELL BODY!
AWAY
The Action potential is an explosion o9f electrical activity.
That is created by depolarizing current.

 Explain the mechanism for action potential

 Action potentials are caused by an exchange of ions across the neuron membrane.
A stimulus first causes sodium channels to open.
Because there are many more sodium ions on the outside, and the inside of the neuron is negative relative to the outside, sodium ions rush into the neuron. Remember, sodium has a positive charge, so the neuron becomes more positive and becomes depolarized. It takes longer for potassium channels to open. When they do open, potassium rushes out of the cell, reversing the depolarization. Also at about this time, sodium channels start to close.

What is the refractory period?

is a period of time during which an organ or cell is incapable of repeating a particular action, or (more precisely) the amount of time it takes for an excitable membrane to be ready for a second stimulus once it returns to its resting state following an excitation.
It most commonly refers to electrically excitable muscle cells or neurons .

 Transmission of nerve impulse from one neuron to another happens how?

 1. Polarization of the neuron's membrane: Sodium is on the outside, and potassium is on the inside.
 2. Resting potential gives the neuron a break.
 3. Action potential: Sodium ions move inside the membrane.
 4. Repolarization: Potassium ions move outside, and sodium ions stay inside the membrane.
 5. Hyperpolarization: More potassium ions are on the outside than there are sodium ions on the inside.
 6. Refractory period puts everything back to normal:
Potassium returns inside, sodium returns outside.

 What are the parts of a synapse ?

 1. a presynaptic ending that contains neurotransmitters , mitochondria and other cell organelles,
2. a postsynaptic ending that contains receptor sites for neurotransmitters and,
3. a synaptic cleft or space between the presynaptic and postsynaptic endings.

 What are the different types of neurogleal cells?

 Astrocytes
 Oligodendrocytes
 Ependymal cells
 Schwann cells
 Satellite cells

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The most abundant type of macroglial cell, astrocytes (also called astroglia ) have numerous projections that anchor neurons to their blood supply. They regulate the external chemical environment of neurons by removing excess ions , notably potassium , and recycling neurotransmitters released during synaptic transmission .
Oligodendrocytes are cells that coat axons in the central nervous system (CNS) with their cell membrane forming a specialized membrane differenciation called myelin , producing the so-called myelin sheath . The myelin sheath provides insulation to the axon that allows electrical signals to propagate more efficiently.
Ependymal cells , also named ependymocytes , line the cavities of the CNS and make up the walls of the ventricles. These cells create and secrete cerebrospinal fluid (CSF) and beat their cilia to help circulate that CSF.

 Similar in function to oligodendrocytes, Schwann cells provide myelination to axons in the peripheral nervous system (PNS).
They also have phagocytotic activity and clear cellular debris that allows for regrowth of PNS neurons.
 Satellite cells are small cells that line the exterior surface of PNS neurons and help regulate the external chemical environment.

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The BRAIN and the SPINAL CORD 

Brocas Area is Involved in language processing , speech or sign production, and comprehension.

What nerve is affected by Bellas Palsy?

THE FACIAL NERVE Of Course 

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What are the components of a reflex arc?

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RELEX ARC CoNSISTs OF 5 MAIN PARTS
Sensory neuron
CNS integration center
And effector {Think Scammer} (scamr)
Motor neuron
Receptor
To remember that these relate to the reflex arc think scammers arc you…..lol

Step 1) Heat ( a stimulus)
Step 2) Pain receptor stimulated
Step 3) Signal passed along sensory neuron
Step 4) Signal passed to relay neuron
Step 5) Signal passed to motor neuron
Step 6) Signal passed to muscle for response
( move hand away from fire)

Question
What type of reflex would a knee jerk be?

Stretch reflex of course…… because there is only one synapse in the circuit needed to complete the reflex. A stretch reflex is a muscle contraction in response to stretching within the muscle. It is a monosynaptic reflex which provides automatic regulation of skeletal muscle length.

 What are the general affects of sympathetic stimulation?

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 dilates pupil increases heart rate dilates air passages in lung reduces gut motility increases blood glucose level reduced urine output sweating shunting of blood to vital organs (skin turns pale, blood to gut is cut off, blood only goes to brain, heart, necessary muscles) piloerector muscles (raise hair and goosebumps )
FIGHT OR FLIGHT REACTION….Think Sympathy for those in a bad situation where they have to feel fight or flight.

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Explain the parasympathetic nervous system…..

 part of the autonomic nervous system which usually prepares the organism to deal more effectively with a situation of peace, rest, and recovery.