2- neurons glia

Question 1

for each of following choose gray or white matter

a) nucleus
b) lemniscus
c) ganglion
d) peduncle
e) cortex
f) funiculus
g) body
h) fasciculus
i) tract

Answer 1

a) nucleus = gray
b) lemniscus = white
c) ganglion = gray
d) peduncle = white
e) cortex = gray
f) funiculus = white
g) body = gray
h) fasciculus = white
i) tract = white

Question 2

Astrocytes

What is their function structurally?

Answer 2

interdigitate with neurons and help fill volume of brain

Question 3

Astrocytes

What is their biochemical function

Answer 3

keep neurons isolated by retrieving neurotransmitter that leaks out of synapse and then recycle back

Question 4

Astrocytes

How does it help maintain ionic equilibrium

Answer 4

soak up K+ that flows out of cells when neurons fire action potential

Question 5

Astrocytes

How is it involved in blood flow regulation

Answer 5

envelops blood vessels in BBB and helps endothelial cell maintain contacts

communicate with endothelial cells to maintain specialized contacts to prevent from freely enter the extracellular space

Question 6

Astrocytes

Function after damage to CNS?

Answer 6

glial scar formation

Question 7

Microglia

Where are located

Answer 7

extend btwn neurons in white and gray matter like astrocytes but NO OVERLAP

Question 8

Microglia

major function

Answer 8

macrophages for surveillance until activated by stimuli and clear debris from brain

Question 9

Oligodendrocyte

Major function
How many axons

Answer 9

myelin production in CNS

multiple axons

Question 10

Oligodendrocyte

what happens when CNS is damaged

Answer 10

inhibit axonal regeneration by phagocytzing the myelin shath

Question 11

Schwann cell

major function
how many axons

Answer 11

myelin production in PNS

one axon

Question 12

Schwann cells

what happens when PNS neuron is damaged

Answer 12

celar debris then line up along endoneurium to give regenerating axons path to grow

Question 13

Dendrite

Major function
How many can there be for each neuron

Answer 13

conduct electrical signal (NOT ACTION POTENTIAL) and integrate signals

many dendrites/neuron

Question 14

Axon

Contains?
Axons > 1 um in diameter usually ____

Answer 14

contains VG ion channels to generate action potential

> 1 um usu myelinated

Question 15

Nissl substance

what is it?
indicates what in neurons

Answer 15

dark staining RER and ribosomes in cell bodies and dendrites
= RNA stain
indicates high metab activity

Question 16

Blood flow in brain regulated by ___

Answer 16

autoregulation of arterioles in the brain

Question 17

Incr in blood pressure in brain causes ____ to maintain diameter

in functional hyperemia, local incr in neuronal activity causes ____ and thus ___

basis for __ and __

Answer 17

incr in vascular tone

incr metabolic demand and thus incr local blood flow

fMRI and PET

Question 18

PET vs. fMRI function

Answer 18

PET = inject tracer in blood

fMRI = blood flow from Hgb properties

Question 19

What is BBB made of?

What is required for substance to enter CNS

Answer 19

made of endothelial cells forming tight junctions so NO FENESTRATIONS

must be actively transported or diffuse through endothelial cell

Question 20

How does astrocytes respond to glutamate

Answer 20

1) absorb glutamate
2) release arachidonic acid
3) enzymatic rxn by P450 to EET
4) EET acts on arterioles to hyperpolarize cell membrane
5) prevents smooth muscle constriction and decr vascular tone
6) vessel dilation, incr blood flow to brain areas releasing glutamate

Question 21

PNS nerve damage is mainly repaired by ___ using what cell type?

Answer 21

regeneration of damaged axons by Schwann cells

Question 22

Mechanism of Schwann cell regenerating damaged PNS axon

Answer 22

1) Schwann line up along endoneurium and secrete growth promoting substance
2) provides path towards synapse

Question 23

How does peripheral nerve damage lead to sensory loss in CNS

Answer 23

1) central terminals of damaged cell emit signals that activate microglia
2) microglia remove synapses and cause reorg of brain areas
3) causes neuropathic pain

Question 24

How does CNS repair neuron damage

Answer 24

clear out neuron; only some areas can regrow

Question 25

How does oligodendrocyte fix damage neuron

Answer 25

1) destroy myelin sheath
2) inhib axonal growth
3) activation of microglia to strip synaptic space
4) activation of astrocytes to form glial scar

Question 26

function of nucleolus

Answer 26

nucleus has large amount of ribosomes (made of RNA) and RER