lecture 2 Flashcards

1
Q

what are the parts to a neuron

A

cell body, dendrite, axon hillock, pre-synaptic cell, post-synaptic cell, synapse, myelin sheath

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2
Q

what is the structure of a nerve

A

many axons in one package - many packages - nerve

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3
Q

what is the white layer around the axon

A

myelin sheath

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4
Q

where are cell bodies bunched at in a nerve

A

nucleus (CNS) or ganglion (PNS)

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5
Q

what is a nerve supplied with and what do they do

A

nutrients, O2, removing waste

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6
Q

what are the three types of glial cells and what do they do

A

microglia - macrophage - destroy old cells into parts
astrocytes - anchor neurons in place, blood brain barrier
oligodendrocytes (CNS) or schwann cells (PNS) - create myelin sheath (phospholipid bilayer)

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7
Q

what are glial cells

A

cells that helps the neuron function but is not part of the neuron

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8
Q

how does a myelin sheath form

A

schwan cells have nucleus, they engulf the axon and wraps itself around it many times

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9
Q

what are the gaps created by myelin sheath called and what type of conduction occurs there

A

nodes of ranvier, saltatory conduction

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10
Q

where does an AP originate

A

axon hillock

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11
Q

what is the resting membrane potential of the axon

A

-70mV

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12
Q

what are axon hillocks and nodes of ranvier rich in

A

sodium channels

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13
Q

what are the types of synaptic transmissions called and how do they work

A

electrically - junctions directly connect pre and post synaptic - ions and current flow through

neurotransmitters - vesicles in pre-synaptic cell binds with plasma membrane for exocytosis, neurotransmitters released into the synapse,, bind to receptors, cause Na channels to open, create another AP

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14
Q

what is in the cytosol compared to the ECF during resting membrane potential

A

cytosol - large anions, high K, low Na, proteins and AA

ECF - high Na, low K

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15
Q

what are the structures used to move ions during an action potential

A

voltage-gated Na channels, voltage-gated K channels, ATPase pump

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16
Q

where do the majority of the body’s ATP go

A

ATPase pump

17
Q

what is the threshold potential voltage

A

-50mV

18
Q

what are the parts to an action potential

A

resting potential, threshold potential, depolarization, repolarization, hyperpolarization

19
Q

what are the components to the voltage-gated Na channel

A

activation and inactivation gate

20
Q

what are the components to the voltage-gated K channel

A

activation gate

21
Q

what happens when the membrane approaches the threshold potential

A

some Na activation gates open, allows for potential to slowly become less negative

22
Q

what happens when membrane reaches threshold potential

A

all Na activation gates open –> depolarization

23
Q

what happens when you reach the peak of depolarization

A

Na inactivation gates slowly close, activation gates are still open

K activation gates slowly open, K leaves the cell, making cytosol more negative again

membrane begins to repolarize

24
Q

what happens at the peak of repolarization

A

K activation gates start to close slowly

Na inactivation and activation gates open slowly

25
Q

what happens when membrane potential starts to fall below threshold after repolarization

A

Na activation gates begin to close

26
Q

what happens at hyperpolarization

A

ATPase pump moves 3 Na out and 2 K in

27
Q

how does saltatory conduction work

A

starts in axon hillock - rich with Na channels

positive charge rushes down axon - node of ranvier, trigger Na channels to open, another Ap generated, positive charge continues to spread

28
Q

what is an internode

A

myelinated region where the current passes through

29
Q

what is the asbsolute refractory period at depolarization

A

all Na channels are open, there are no more Na channels that can allow for more Na to come in for another AP

30
Q

what is the absolute refractory period at repolarization

A

Na activation gates are closed because of high membrane potential - AP increasing potential will further close gates

31
Q

what is the relative refractory period

A

after mid repolarization, another AP can be generated

32
Q

what are the types of chemical synapses

A

excitatory - cause Na channels to open for new AP

inhibitory - cause Cl channels to open, makes membrane more negative so more stimulus is needed for a new AP