ANATOMY - nervous system

Question 1

what does the CNS consist of

Answer 1

spinal cord and brain

Question 2

which part of a neurone passes on action potentials (APs)

Answer 2

axons

Question 3

which part of a neurone receives action potentials (APs) from another neurons axon

Answer 3

dendrite

Question 4

what is ‘the powerhouse’ of the neurone

Answer 4

body/soma

Question 5

what is in the body/soma of the neurone that classifies it as the ‘powerhouse’ of the neurone

Answer 5

mitochondria
ribosomes
nucleus/ganglion
ER

etc

Question 6

which part of the neurone is in between the body/soma and the axon

Answer 6

axon hillock

Question 7

what is the significance of the axon hillock

Answer 7

generates most action potentials (APs)

Question 8

what is the difference between a nucleus and a ganglion

Answer 8

ganglion is found in PNS
nucleus is found in CNS

both parts of the neuron body/soma

Question 9

how does neuronal injury occur

Answer 9

ischaemia/hypoxia

Question 10

which part of the brain has most neurones

Answer 10

cerebellum

Question 11

what is a nerve

what is a tract

(clue: theyre similar)

Answer 11

nerve - collection of axons in PNS

tract - collection of axons in CNS

Question 12

where is the myelin sheath

what is its purpose

Answer 12

wraps around axons

insulator/conductor = faster AP transmission speed

Question 13

what is the function of a schwann cell/oligodendrocyte

Answer 13

produce myelin

Question 14

where are oligodendrocytes and schwann cells found (CNS/PNS)

Answer 14

oligodendrocytes - in CNS

schwann cells - in PNS

Question 15

what is the difference in function between a multipolar and unipolar neurone

Answer 15

multipolar - motor signals (from CNS to PNS - so body in CNS)
think multipolar because motor signals need to go to more than one place (lots of diff parts of one muscle)

unipolar- sensory signals (from PNS to CNS - so body in PNS)
think unipolar bc sensory signals come from one specific place and go to one specific location

Question 16

where is the body/soma of a unipolar neurone

Answer 16

PNS (bc that’s where it originates)

Question 17

where is the body/soma of a multipolar neurone

Answer 17

CNS (bc that’s where it originates)

Question 18

what is another name for a multipolar neurone

Answer 18

lower motor neurone (LMN)

Question 19

what are the 4 types of glial cells

Answer 19

astrocytes
oligodendrocytes
microglia
ependymal cells

Question 20

what is the purpose of astrocytes

Answer 20

maintain blood brain barrier

Question 21

what does damage to astrocytes look like on histopathology

Answer 21

gliosis - increase in number and size, old lesions become dark

Question 22

what do astrocytes normally look like on histopathology

Answer 22

star shaped

Question 23

what is the most important histopathological marker of CNS damage

Answer 23

astrocyte gliosis

Question 24

what do oligodendrocytes do

Answer 24

produce myelin for axons in the CNS

Question 25

what is the purpose of the myelin sheath

Answer 25

insulator around the axons = increases conduction velocity of APs

Question 26

how many myelin sheaths does an oligodendrocyte produce

Answer 26

lots! - in between several axons

Question 27

in what conditions are myelin sheaths and oligodendrocytes important give 2 examples

Answer 27

demyelinating disorders eg multiple sclerosis, guillane barre

Question 28

what is damaged in demyelinating disorders what does this result in

Answer 28

oligodendrocytes (in CNS not schwann cells in PNS) decreased myelin sheaths = slowed conduction of signals from brain to body and vice versa

Question 29

what is the node of ranvier

Answer 29

in areas where the axon is exposed as there is no myelin sheath coverage (unmyelinated part of axon)

Question 30

what is the significance of the node of ranvier

Answer 30

precipitates rapid saltatory conduction

Question 31

what types of cell are microglia

Answer 31

immune cells

Question 32

when do you see microglia

Answer 32

when damage has happened (there to fix the problem - immune cells)

Question 33

what are ependymal cells

Answer 33

cells (epithelium) lining the ventricles

Question 34

when do ependymal cells get damaged

Answer 34

by viruses

Question 35

is there connective tissue in CNS

Answer 35

no apart from around blood vessels

Question 36

how fast is the damage if necrosis has occurred

Answer 36

fast eg stroke

Question 37

how fast is the damage if atrophy has occurred

Answer 37

slow eg age related cerebral atrophy

Question 38

where do sympathetic nerves leave the spinal cord

Answer 38

T1-L2 (thoracolumbar region)

Question 39

what happens to sympathetic nerves once they leave the spinal cord (to heart and lungs)

Answer 39

synapse in ganglia next to the spinal cord (PARAvertebral ganglia) then travel through cardiopulmonary splanchnic nerves to heart and lungs

Question 40

what happens to sympathetic nerves once they leave the spinal cord (to abdominopelvic organs)

Answer 40

synapse away from the spinal cord (PREvertebral ganglia) | then travel to applicable organs via specific nerves

Question 41

which 4 cranial nerves do ALL parasympathetic outflow leave the brain via

Answer 41

CN III, VII, IX, and X (mainly vagus but others too) plus sacral spinal nerves (to pelvis, perineum and hindgut)