NS

Question 1

nucleus of neuron is in…

Answer 1

soma

Question 2

soma is the location of which two organelles?

Answer 2

ER and ribosomes

Question 3

dendrites

Answer 3

appendages emanating directly from the soma receiving incoming messages from other cells

Question 4

axons hillock

Answer 4

• receives information sent from dendrites through soma and integrates incoming signals
• summation of the inhibitory and/or excitatory signals from dendrites until threshold is reached initiating an AP

Question 5

axon

Answer 5

myelin sheath wraps around axon and APs are conducted through this structure until reaching the axon terminal

Question 6

myelin

Answer 6

fatty membrane preventing signal loss or crossing of signals

Question 7

myelin sheath

Answer 7

maintain electrical signal within one neuron, inc conduction speed

Question 8

In CNS myelin is produced by…

Answer 8

oligodendrocytes

Question 9

In PNS myelin is produced by…

Answer 9

Schwann cells

Question 10

nodes of Ranvier

Answer 10

gaps between sheath

Question 11

nerve terminal

Answer 11

flat and large to maximize signal transmission and release of NTs to move through synaptic cleft and bind to dendrites of postsynaptic neuron

(nerve terminal, synaptic cleft, and postsynaptic membrane ~> synapse)

Question 12

nerve

Answer 12

multiple neurons bunbled together in PNS

can be sensory, motor, or mixed

cell bodies of neurons of the same type are clustered together into ganglia

Question 13

tracts

Answer 13

axons bundled together in CNS

only carry one type of info

cell bodies of tract are grouped into nuclei

Question 14

glial cells

Answer 14

cells that support and myelinate neurons

Question 15

astrocyte

Answer 15

• form BBB (controls transmission of solutes from bloodstream into nervous tissue)
• nourish neurons

Question 16

ependymal cells

Answer 16

• line ventricles of brain and produce cerebrospinal fluid
• physically supports brain and acts as a shock absorber

Question 17

microglia

Answer 17

phagocytic cells that ingest and break down waste products and pathogens in CNS

Question 18

oligodendrocyte (CNS) and Schwann cell (PNS)

Answer 18

produce myelin around axons

Question 19

neuronal resting potential

Answer 19

~ -70 mV (inside neurons relatively neg)

K+ 140 mM inside 4mM outside hence potassium leak channels
BUT
equilibrium potential of ~ -90 mV (moving out)

Na+ 12 mM inside 145 mM outside hence sodium leak channels
BUT
equilibrium potential of ~ 60 mV (moving in)

Question 20

threshold value

Answer 20

~ -55 mV to -40 mV

Question 21

excitatory input causes

Answer 21

depolarization

Question 22

inhibitory input causes

Answer 22

hyperpolarization

Question 23

what are the two types of summation?

Answer 23

temporal and spatial

Question 24

temporal summation

Answer 24

• multiple signals integrated during a relatively short period of time

Question 25

spatial summation

Answer 25

- the additive effects are based on the number and location of the incoming signals

Question 26

sodium channel behavior during AP

Answer 26

- closed before ~ -55 to -40 mV - open from threshold to +35 mV - inactive +35 mV to resting potential

Question 27

the effluent of K+ causes…

Answer 27

- overshoot of resting membrane potential - hyperpolarization of the neuron - absolute vs relative refractory periods - resting potential restored by Na+/K+ ATPase

Question 28

impulse propagation

Answer 28

- as sodium rushes into one segment of the axon, it will cause depolarization in the surrounding regions - sodium channels of other segments then open and action potential propagated like a wave through the axon and each segment that it’s passed through becomes momentarily refractory - speed of impulse propagation depends on length and cross sectional area of the axon (inc length means higher resistance and slower conduction, but inc cross sec area allows for faster propagation due to dec resistance and this effect is more powerful than length)

Question 29

saltatory conduction

Answer 29

- membrane only permeable to ion movement at nodes of Ranvier bc of myelin insulation - signal hop node-to-node

Question 30

same type of neuron…

Answer 30

same potential diff inc stimulus intensity means inc firing frequency NOT inc potential diff

Question 31

how does the calcium get into the presynaptic cell to release the NT?

Answer 31

voltage-gated Ca channels open

Question 32

postsynaptic receptor types

Answer 32

- G-coupled: either levels of cAMP altered or influx of calcium - ligand-gated ion channels: depolarization or hyperpolarization upon binding

Question 33

how can NT be removed from cleft

Answer 33

1) enzyme (acetylcholinesterase) 2) reuptake (5-HT, DA, NE) 3) diffuse out (nitric oxide)

Question 34

the brain consists of…

Answer 34

white matter ~> axons encased in myelin sheaths (lies deeper than grey matter) grey matter ~> unmyelinated cell bodies and dendrites

Question 35

cell bodies of sensory neurons can be found in…

Answer 35

DRG

Question 36

parasympathetic NS main NT

Answer 36

acetylcholine released by both pre and postganglionic neurons

Question 37

sympathetic NS main NTs

Answer 37

preganglionic neurons release ACh and post release NE

Question 38

monosynaptic reflex arc

Answer 38

single synapse between sensory neuron and motor neuron knee jerk: patellar tendon stretched, info travels up sensory neuron, synapses onto motor neuron, which causes contraction of quad

Question 39

polysynaptic reflex arc

Answer 39

at least one interneuron between sensory and motor withdrawal reflex