peripheral nervous system and neuromuscular junction

Question 1

what is the PNS split into

Answer 1

motor and sensory

Question 2

what is motor split into

Answer 2

somatic and autonomic

Question 3

what is autonomic split into

Answer 3

parasympathetic and sympathetic

Question 4

embryology of nervous tissue

Answer 4

neural ectoderm

Question 5

what does non-neural ectoderm give rise to

Answer 5

skin

Question 6

where do all sensory neurones in PNS arise from

Answer 6

neural crest which arises from neural ectoderm

Question 7

derivatives of neural crest cells

Answer 7

pseudounipolar sensory neurones and Schwann cells

Question 8

sensory neurone basic structure

Answer 8

soma, axon, dendrites and sensory receptor

Question 9

what is a ganglion

Answer 9

cluster of nerve cell somas

Question 10

what are A fibers

Answer 10

myelinated somatic

Question 11

what are B fibers

Answer 11

myelinatd visceral (internal)

Question 12

what are C fibers

Answer 12

unmyelinated pain afferents

Question 13

function of PNS

Answer 13

communication between CNS and body; everything outside CNS

Question 14

function of sensory division

Answer 14

conducts signals from receptors to CNS

Question 15

function of somatic motor division

Answer 15

controls voluntary movement

Question 16

function of autonomic motor division

Answer 16

controls automatic movement

Question 17

what is the function of upper motor neurones

Answer 17

connect to CNS in primary motor cortex

Question 18

what is the function of lower motor neurones

Answer 18

sends to effector muscles in rest of body

Question 19

where are somatic motor nuclei

Answer 19

brain stem or spinal cord

Question 20

what is the basal plate

Answer 20

where lower motor neurones originate from in spinal cord

Question 21

innovation of muscles by motor neurones

Answer 21

1 multipolar motor neurone innovates many muscle fibres at neuromuscular junction

Question 22

where are the sensory ganglion in the spinal cord

Answer 22

dorsal root

Question 23

function of dorsal horn

Answer 23

receives sensory information from sensory neurones

Question 24

function of ventral root

Answer 24

send effector response via motor neurones

Question 25

what is the mixed spinal nerve

Answer 25

where both sensory and motor neurones are present in grey matter

Question 26

how many pairs of cranial nerves

Answer 26

12

Question 27

how many pairs of spinal nerves

Answer 27

31

Question 28

1st motor neurone of ANS: origin and features

Answer 28

from hypothalamic nuclei to brain stem nuclei or spinal cord; myelinated

Question 29

2nd motor neurone of ANS: type

Answer 29

pre-ganglionic neuron

Question 30

2nd motor neurone of ANS: origin and features

Answer 30

from brain stem nuclei or spinal cord to autonomic; myelinated

Question 31

2nd motor neurone of ANS: when is it a pre-synaptic neurone

Answer 31

if from vagal nerve and sacral parasympathetic nerves

Question 32

3rd motor neurone of ANS: type

Answer 32

post-ganglionic neurone

Question 33

3rd motor neurone of ANS: origin and features

Answer 33

from autonomic ganglia to visceral effectors; unmyelinated

Question 34

3rd motor neurone of ANS: when is it a post-synaptic neurone

Answer 34

if associated with vagal nerve and sacral parasympathetic nerves

Question 35

features of vagal and sacral parasympathetic nerves

Answer 35

no ganglia so presynaptic and postsynaptic neurone

Question 36

developmental biology of ANS: features incl. type of fibre

Answer 36

multipolar, myelinated B fibres, basal plate, pre-ganglionic sympathetic neurones or pre-synaptic parasympathetic neurones

Question 37

derivatives of neural crest cells

Answer 37

multipolar, unmyelinated C fibres, post-ganglionic (sympathetic or parasympathetic neurones) or post-synaptic parasympathetic neurones

Question 38

PNS functional components: somatic motor neurones

Answer 38

CNS → skeletal muscle

Question 39

PNS functional components: autonomic motor neurones

Answer 39

CNS → blood vessels; if no dorsal root ganglia, contains synapses instead between pre and post-ganglionic neurones

Question 40

PNS functional components: sensory neurones

Answer 40

skin receptor → ganglion → CNS

Question 41

myelination: what is the minor dense line

Answer 41

plasma membrane of Schwann cells

Question 42

myelination: what is the major dense line

Answer 42

location where cytoplasm condenses

Question 43

characteristics of A fibres

Answer 43

up to 100 layers of Schwann cells; largest fibre; myelinated somatic; sensory and motor to skeletal muscle

Question 44

characteristics of B fibres

Answer 44

myelinated visceral; sensory and autonomic preganglionic

Question 45

characteristics of C fibres

Answer 45

smallest fibre; unmyelinated; sensory and autonomic; not completely naked but contains cytoplasm of Schwann cell only (neurilemma) so many C fibres associated with one Schwann cell

Question 46

ANS rootlets, roots, rami and ganglia: where do pre-ganglionic fibres synapse

Answer 46

in ganglion

Question 47

ANS rootlets, roots, rami and ganglia: 3 passages of pre-ganglionic fibres in spinal cord

Answer 47

post-ganglionic fibres could exit in same ganglion via grey ramus in spinal nerve; pre-ganglionic fibre could move (up or down) 1 or 2 ganglion then exit; pre-ganglionic fibre could pass through white ramus and into splanchnic nerve to post-ganglionic sympathetic fibres

Question 48

ANS ganglia: parasympathetic location

Answer 48

cranial

Question 49

ANS ganglia: sympathetic location

Answer 49

paravertebral and collateral