Nerve Cell Function and Synaptic Transmission (Neurophysiology I) Flashcards

1
Q

What structures are part of the CNS?

A

Brain + spinal cord

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the function of the CNS?

A
  • make decisions
  • integration center
  • operating system of body
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the function of the PNS?

A
  • move info from CNS to target cells
  • move info from outside environment to CNS
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is afferent movement?

A

information from PNS travels to CNS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is efferent movement?

A

information travels from CNS to PNS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What does the sensory system consist of? Is it afferent or efferent movement?

A
  • sensory nerve fibers
    -afferent
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Describe the somatic systems components + function. Is it afferent or efferent?

A
  • motor nerve fibers travel to skeletal muscles
  • controls movement
  • efferent
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Describe the autonomic systems components + function. Is it afferent or efferent?

A
  • motor nerve fibers to glands, heart + smooth muscle

-efferent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What two systems are part of the autonomic system? What are their functions?

A

Sympathetic NS - fight or flight
Parasympathetic NS - rest + digest

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is nervous tissue made of?

A

neurons + glial cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the functions of neurons?

A

generate, transmit + integrate information

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the purpose of an axon?

A

move information away from cell body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the purpose of a dendrite?

A

move information towards cell body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the purpose of the cell body?

A

integrates in + outgoing information

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is a multipolar neuron and where is it located?

A
  • multiple dendrites
  • CNS
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is a pseudounipolar neuron? Where is it located?

A
  • continuous axon that bypasses cell body
  • PNS
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is a bipolar neuron? Where is it located?

A
  • 1 dendrite + 1 axon
  • sensory organs
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the function of a sensory neuron?

A
  • move information from PNS to CNS (afferent)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the function of a motor neuron?

A

move information from CNS to muscles + glands (efferent)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the function of interneurons (association)?

A

relay info between neurons within the CNS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is the function of specialized receptors (transducers)?

A

converts stimuli into signal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What are glial cells? Name 4 types.

A
  • non-neuronal cells
  1. oligodendrocytes
  2. astrocytes
  3. ependymal cells
  4. microglia
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What neurons not store?

A

glucose + oxygen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What are the functions of glial cells?

A
  • provide structural support to nervous tissue
  • participate in myelin formation
  • secrete glutamate
  • possesses phagocytic activity
  • contacts blood vessels + neurons for nutrient transport
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What glial cell participates in myelin formation?

A

oligodendrocytes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What glial cell participates in phagocytic activity?

A

microglia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What glial cell participates in glutamate secretion + why?

A
  • modulates excitatory levels of neurons
  • astrocytes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What is grey matter + where is it located?

A
  • high density cell bodies
  • nerve cells + integration center
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What is white matter? What gives it the white appearance?

A
  • bundles of neuron processes
  • myelin sheath
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What is ganglia? Where is it located?

A
  • clusters of cell bodies of sensory neurons
  • outside CNS
31
Q

What is myelin + what is it made of?

A
  • white lipid around nerve fibers
  • made of phospholipids
32
Q

What is the function of myelin sheaths?

A

acts as electrical insulate to allow for faster AP transmission between nodes of Ranvier

33
Q

True or False: Denuded axon points allow depolarization + transmission of AP?

A

True

34
Q

What is the impact of no myelin sheath?

A

slow transmission of AP

35
Q

Where are oligodendrocytes located?

A

CNS

36
Q

Where are schwann cells located?

A

PNS

37
Q

What are the charges in RMP?

A
  • inside membrane (cytosol) = (-)
  • outside membrane = (+)
38
Q

What are 3 ways to maintain RMP?

A
  • selective permeability
  • Na+/K+ pump
  • trap large anions on inner surface of membrane
39
Q

What happens with selective permeability when maintaining RMP?

A
  • allows passive leakage of ions through channels following concentration gradient
40
Q

Where do positive charges accumulate in RMP?

A

outside

41
Q

What ion is most permeable + what direction does it move (outside to inside OR inside to outside)

A

K+

-leaks inside to outside

42
Q

Explain ion pumps in maintaining RMP.

A

Na+/K+ pump moves 3 Na+ out of cell + brings 2 K+ into cell to keep concentration of ions relatively constant

43
Q

What does the ion pump do differently than passive diffusion?

A

goes against concentration gradient

44
Q

What does Na+ go against in Na+/K+ pump?

A

goes against membrane polarity as outside is already (+)

45
Q

Does the ion pump require energy?

A

Yes. Approx 40% ATP

46
Q

What induces a change in membrane potential? Why?

A

chemical, physical or electrical stimuli

  • provokes opening of voltage gated ion channels to allow for AP
47
Q

Explain the action potential in neurons?

A

Depolarization:
- Na+ channels open allowing Na+ into cell
- inside more (+)

Repolarization:
- K+ channels open allowing K+ to flow outside
- returns potential to RMP

Hyperpolarization:
- K+ voltage gated channels begin to close
- outflow of K+ continues by passive diffusion
- ions return to proper places by diffusion + Na+/K+ pump once gated channels close

48
Q

What is the refractory period?

A

period in which neurons cannot be re-stimulated until RMP is restored

49
Q

What do ligand-gated channels bind?

A

neurotransmitters

50
Q

What is the function of gap junction channels?

A
  • direct communication between 2 cells
  • helps all cell depolarize at once
51
Q

What is the all-or-none rule?

A

if threshold is reached, generate AP (depolarization)

if threshold not reached, no AP (no depolarization)

52
Q

Why can an action potential not move backwards?

A

membrane that was just depolarized is now in refractory period

53
Q

What is saltatory conduction?

A
  • myelin prevents ion leakage
  • current jumps from one node to next
54
Q

What happens to velocity in a myelinated axon? Why does this happen?

A
  • increases velocity
  • less energy required to transport ions
55
Q

What impacts nerve velocity?

A
  • thickness of myelin
  • diameter of fiber (thicker = faster)
56
Q

What is a neuromuscular synpase?

A

continuity of signal between neuron + target cell

57
Q

What is the synaptic cleft?

A

gap between pre + post synaptic membrane

58
Q

What is a gap junction? Where does this happen?

A
  • AP jumps from one cell to another
  • cardiac + some smooth muscle
59
Q

What is a neurotransmitter?

A

molecule able to transmit information from neuron

60
Q

Explain how a neurotransmitter functions.

A
  1. converts AP into chemical signal
  2. released by pre-synaptic neuron into gap
  3. binds to specific receptor on post-synaptic membrane
  4. elicits a response
61
Q

How is a neurotransmitter classified?

A
  • small molecules vs. neuropeptides (3-40 AA)
62
Q

Where are small molecule neurotransmitters produced?

A

produced locally in nerve terminals

63
Q

Where are neuropeptides produced + stored for transport?

A
  • produced in cell body + comes from expression of gene
  • packaged into secretory vesicles during transport
64
Q

Explain the neuromuscular synapse.

A
  1. AP generated
  2. voltage gated Ca2+ channels cause influx of Ca2+
  3. Ca2+ triggers exocytosis (vesicles dock to membrane)
  4. diffusion in cleft
  5. ACh binds to specific receptors
  6. ion channels open on post-synaptic membrane causing depolarization (Na+ flows inside ligand-gated channel)
  7. ACh inactivated + signal termination
65
Q

What neuromuscular synapse transmitter is used?

A

Acetylcholine

66
Q

What is common in neuromuscular synpase to increase surface?

A

post-synaptic folding

67
Q

What happens to small molecules upon termination of transmission?

A
  • picked up by presynaptic neuron via endocytosis + recycled
  • deactivated by ACh esterase (AChE) in the cleft
68
Q

What happens to neuropeptides upon termination of transmission?

A
  • can be internalized by post-synpatic cell via endocytosis + degraded by enzymes

OR

  • broken down by extracellular peptidase in the gap
69
Q

What happens to the receptor when transmission is terminated?

A
  • receptor becomes desensitized (saturated + cannot generate AP)
70
Q

What does a neuro-muscular synapse consist of?

A
  • 1 neuron (integrates information)
  • AP
  • muscle cell depolarization
71
Q

What does a neuron-neuron synapse consist of? Does it always lead to a response?

A
  • 1 neuron that receives impulse from other neurons
  • synapse can be excitatory or inhibitory
  • no as impulse must reach threshold to elicit a response
72
Q

What happens in an excitatory synapse?

A
  • depolarization
  • entry of Na+
73
Q

What happens in an inhibitory synapse?

A
  • hyperpolarization
  • entry of Cl-
  • outflow of K+