L8 - Neurons and Glia

Question 1

describe some features of the structure of neurones

Answer 1

RER / ribosomes / nucleus / mitochondria / golgi
dendrites
synapses
dendritic spines 
axon hillock 
axon

Question 2

name the 3 layers of the peripheral nervous system

Answer 2

endoneurium (innermost)
perineurium
epineurium (outermost)

Question 3

describe endoneurium

Answer 3

innermost

delicate connective tissue layer that surrounds individual axons and associated schwann cells

Question 4

describe perineurium

Answer 4

middle layer
connective tissue
surrounds groups of axons creating fascicles

Question 5

describe epineurium

Answer 5

outermost
robust connective tissue layer surrounds fascicles
contains blood vessels

Question 6

what is the myelin sheath made of and what is its purpose

Answer 6

schwann cells wrapped around axon

allows saltatory conduction (quicker conduction)

Question 7

how can neurons be classified by their function

Answer 7

afferent (sensory) - generate A.P towards CNS
efferent (motor) - generate A.P away from CNS
interneurons - connect neurons in CNS

Question 8

what are the 3 major structural classifications of neurons

Answer 8

1. bipolar
2. psuedo - unipolar
3. multipolar

Question 9

describe bipolar neurons and give an example

Answer 9

2 processes leave the cell body
(axon and dendrite)
sesory in retina

Question 10

which direction does is the axon and dendrite?

Answer 10

axon - Away from cell body

dendrite - towards cell body

Question 11

describe psuedo - unipolar neurons and give example

Answer 11

appears to have 2 processes but has 1 that splits as soon as it leaves cell body
ganglia to spinal cord

Question 12

describe multipolar and give example

Answer 12

many processes leave cell body (dendrites)

eg motor neurons

Question 13

define convergence

Answer 13

when several pre synaptic neurons converge on single post synaptic neurone

Question 14

define divergence

Answer 14

when pre synaptic neurone diverges into many branches of post synaptic neurons

Question 15

function of glia

Answer 15

provide support for neurons

Question 16

classes of CNS glia

Answer 16

astrocytes
oligodendrocytes
ependymal cells
microglia

Question 17

example of PNS glia

Answer 17

schwann cell

Question 18

describe astrocyte structure

Answer 18

star shaped

Question 19

what is most abundant glia in brain

Answer 19

astrocytes

Question 20

structural roles of astrocytes

Answer 20

Fill spaces between neurons
Support of the blood-brain barrier
Forms the glial limitans

Question 21

homeostatic roles of astrocytes

Answer 21

regulates levels of :
water
k+
neurotransmitters

Question 22

what do astrocytes and oligodendrocytes inhibit

Answer 22

axon regeneration

Question 23

describe oligodendrocyte structure

Answer 23

many branches

Question 24

oligodendrocyte function

Answer 24

myelinating axons in CNS

Question 25

what myelinates axons in
PNS
CNS

Answer 25

schwann cells

oligodendrocytes

Question 26

where are ependymal cells found

Answer 26

lining brain ventricles
lining spinal cord central canal
choroid plexus

Question 27

what do specialised ependymal cells form? and what does this do

Answer 27

choroid plexus

found within brain ventricles and secretes Cerebral Spinal Fluid

Question 28

what are microglia

Answer 28

specialised macrophages

Question 29

function of microglia

Answer 29

respond to inflammation/microorganisms/debris/phagocytes/necrotic tissue

Question 30

in nerve cells where do action potentials initiate

Answer 30

axon hillock

Question 31

what disease is associated with demyelination of axons

Answer 31

MS

Question 32

which way do afferent nerves carry impulses

Answer 32

towards CNS

Question 33

which way do efferent nerves carry impulses

Answer 33

away from CNS