1 - Intro to Neuroanatomy & Neurocytology

Question 1

2 cell types: ____ (nerve cells) and ___ (non-neuronal cells)

Answer 1

neurons, glia

Question 2

____: anatomical and functional units for signal transmission

Answer 2

neurons

Question 3

____: supportive structural matrix, maintains homeostasis, nourishment, regulation of neuronal functions

Answer 3

glia

Question 4

4 anatomical components of neuron?

Answer 4

1. dendrites
2. soma (cell body)
3. axon
4. presynaptic axon terminal

Question 5

do dendrites send or receive signals?

Answer 5

receive

Question 6

do axons send or receive signals?

Answer 6

send

Question 7

____ neurons: 1 dendrite root and 1 axon with cell body central to those

Answer 7

bipolar

Question 8

______ neurons: 1 dendrite root and 1 axon with cell body not in the exact middle

Answer 8

pseudounipolar (subclass of bipolar)

Question 9

_____ neurons: multiple dendrites & 1 axon

Answer 9

multipolar (most common)

Question 10

3 functional classifications of neurons?

Answer 10

1. motor neurons
2. sensory neurons
3. interneurons

Question 11

___: supporting cells, “glue” of nervous system

Answer 11

glia

Question 12

3 types of macroglia?

Answer 12

1. astrocytes
2. oligodendrocytes
3. schwann cells

Question 13

astrocytes found in CNS or PNS?

Answer 13

CNS

Question 14

oligodendrocytes found in CNS or PNS?

Answer 14

CNS

Question 15

schwann cells found in CNS or PNS?

Answer 15

PNS

Question 16

____: star shaped cells that include neuronal signaling (liaison, communications, pathways for neuronal migration), housekeeping, nutritive functions for neurons

Answer 16

astrocytes

Question 17

_____: form myelin sheath in CNS

Answer 17

oligodendrocytes

Question 18

____: form myelin sheath in PNS

Answer 18

schwann cells

Question 19

_____: type of glial cells that work as immune system of CNS, function as phagocytes, activate during nervous system development, activate after injury or infection

Answer 19

microglia

Question 20

3 types of glial cells?

Answer 20

glia, macroglia, microglia

Question 21

____ is effective insulator, shielding neurons from extracellular environment, and helps speed up transmission

Answer 21

myelin

Question 22

4 steps in sequence of events for neural transmission?

Answer 22

1. receptor stimulated
2. local potential
3. action potential
4. synapses

Question 23

___ potential:
- small, graded potential in amplitude and duration
- receptor or synaptic potential
- spreads passively and confined to small area of neuron membrane

Answer 23

local

Question 24

___ potential:
- large, “all or none” depolarizing signal
- actively propagates along neuron axon traveling 1-way to presynaptic terminal

Answer 24

action

Question 25

____: transports signal to other neurons by release of neurotransmitters

Answer 25

synapses

Question 26

neurons have ____ ____ membranes

Answer 26

selectively permeable

Question 27

cell membrane is more permeable to __ than to ___

Answer 27

K+, Na+

Question 28

____ ____: separation of different charges across the membrane creating electrical potential (___ mV)

Answer 28

membrane potential, -70

Question 29

extracellular fluid is more ____ charged, intracellular fluid is more ___ charged when at resting membrane potential

Answer 29

extracellular = + intracellular = -

Question 30

what channel? ____ (____): small amount of ions diffuse through membrane at slow continuous rate

Answer 30

leak (non-gated)

Question 31

what channel? _____ (___ ___ only): opens in reaction to mechanical stimulation, temperature or chemicals

Answer 31

modality-gated (sensory neurons only)

Question 32

what channel? ______: opens when neurotransmitter binds to post-synaptic receptors, generating local potentials

Answer 32

ligand-gated

Question 33

what channel? _____: opens in reactions to change in electrical potential, generating actions potentials

Answer 33

voltage-gated

Question 34

At rest, inside of neuron is more (-) than outside: - inside with more ___ and ____ - outside with more ___ and ____

Answer 34

inside with more K+ and anions- outside with more Na+ and Cl-

Question 35

Dynamic equilibrium of RP is maintained by: - (-) charged anions trapped ____ neuron - passive diffusion of __ and ___ thru leak channel - Na+ and K+ pump requiring ____

Answer 35

- inside - K+ and Na+ - ATP

Question 36

Na+ - K+ pump: ___ K+ into cell and ___ Na+ out

Answer 36

2, 3

Question 37

Na+ - K+ pump: 2 K+ ___ cell and 3 Na+ ___ of cell

Answer 37

into, out

Question 38

when is it easier for the nerve to conduct, when depolarized or hyperpolarized?

Answer 38

depolarized

Question 39

Stim has to reach threshold of ___mV to produce action potential

Answer 39

-55

Question 40

will increasing stim intensity change amplitude or duration of AP?

Answer 40

no

Question 41

Action potential: - actively propagates along ____ - repeatedly generates signal - travels in ___ direction - can be produced by ___ or ___ summation

Answer 41

axon 1 spatial, temporal

Question 42

___ ___ phase: more + from -70mV to +30 mV

Answer 42

rising depolarizing phase

Question 43

____ ____ phase: more - from +30mV to -70mV

Answer 43

falling repolarizing phase

Question 44

___ ____ phase: more - than RP at -90mV

Answer 44

re-setting hyperpolarizing

Question 45

depolarization: small change in membrane voltage depolarizes it enough to open ___ channels

Answer 45

Na+ (voltage-gated Na+ channels)

Question 46

Depolarization: - small change in membrane voltage depolarizes it enough to open Na+ channels - as more Na+ moves into the neuron, more and more Na+ channels open - polarity rapidly changes to ___ from ___ to produce ___ ____

Answer 46

negativeto +, action potential

Question 47

Repolarization to hyperpolarization to RP: - ___ channels start to close and ___ voltage-gated channels start to open

Answer 47

Na+, K+

Question 48

K+ channels are ___ to respond to the AP's depolarization

Answer 48

slower

Question 49

Repolarization to hyperpolarization to RP: - Na+ channels start to close and K+ voltage-gated channels start to open - K+ ions exit and membrane potential falls toward RP from + to - toward -70mV - K+ channels remain open leading to ____ membrane potential (below -70mV) - gradually active _____ ____ the ions to restore RP of -70mV

Answer 49

hyperpolarized Na+-K+ pumps

Question 50

what refractory period? ____: completely unresponsive to stimuli

Answer 50

absolute

Question 51

what refractory period? ____: most of Na+ channels have been open and not yet reset to resting state

Answer 51

absolute

Question 52

what refractory period? ___: may respond to stronger stimuli

Answer 52

relative

Question 53

what refractory period? ____: most of Na+ channels are reset

Answer 53

relative

Question 54

refractory period advantageous for promotion of ___ propagation of AP and prevent ___ flow

Answer 54

forward, backward

Question 55

3 factors influencing action potential conduction velocity?

Answer 55

1. diameter of axon 2. myelin 3. temperature

Question 56

__ ___ __: - placed q 0.2 to 2 mm - location of AP generation and voltage-gated Na+ channels

Answer 56

nodes of ranvier

Question 57

___ ___: AP leaps from node to node

Answer 57

saltatory conduction

Question 58

___ occurs only at nodes of ranvier

Answer 58

depolarization

Question 59

___ conduction: - AP propagates along unmyelinated axon membrane - step by step depolarization of each part of length of axon - as Na+ flows into cell, voltage of next areas is impacted and their voltage-gated Na+ channels open

Answer 59

continuous

Question 60

will continuous or saltatory conduction be faster?

Answer 60

saltatory

Question 61

____ ____ fibers: peripheral sensory and motor axons

Answer 61

large myelinated

Question 62

___ ____ fibers: - short axons in gray matter of CNS - some visceral autonomic axons - some pain fibers

Answer 62

thin unmyelinated

Question 63

Action potential in muscle cell: - resting skeletal and cardiac muscle resting potential is ____mV - resting visceral smooth muscles are ___mV to ____mV - muscle AP lasts ___ msec - cardiac and smooth muscle AP lasts ____ msec

Answer 63

-90mV -20 to -50mV 1-5msec 10-300msec

Question 64

Action potential in nerves: - resting membrane potential is ___mV - nerve AP is ____msec - fasters nerve conduction is ___x faster than velocity over skeletal muscle fibers

Answer 64

-70mV 0.5-2msec 18x