nervous tissue

Question 1

what is the perikaryon

Answer 1

the cell body of the neuron

Question 2

what extends from the cell body of the neuron

Answer 2

an axon and dendrites

Question 3

what are dendrites

Answer 3

highly branched tapering processes which end in either specialised receptors or form synapses with neighboring neurons they receive stimuli from

Question 4

what are primary sensory neurons

Answer 4

those with dendrites that end in specialisaed sensory receptors

Question 5

what is the function of dendrites

Answer 5

major sites of information input into the neuron

Question 6

what do axons carry information from

Answer 6

perikaryon

Question 7

what do axons carry information to

Answer 7

synapse

Question 8

in which neurons are schwann cells found

Answer 8

in those of the peripheral nervous system

Question 9

what is the function of schwann cells

Answer 9

envelop PNS axons to provide structural and metabolic support

Question 10

what are small diameter axons

Answer 10

those of the autonomic nervous system and pain fibres

Question 11

what envelops small diameter axons

Answer 11

the cytoplasm of schwann cells - meaning they are unmyelinated

Question 12

what are large diameter fibres wrapped by

Answer 12

variable number of cocentric layers of the schwann cell plasma membrane to form a myelin sheath

Question 13

what provides the myelin sheath to axons of the peripheral nervous system

Answer 13

many schwann cells

Question 14

what provides the myelin sheath in the central nervous system axons

Answer 14

oligodendrocytes

Question 15

how much of the axon can be covered by a single schwann cell

Answer 15

only a segment

Question 16

what are nodes of ranvier

Answer 16

short intervals where the axon is not covered by myelin, found in between the schwann cells

Question 17

what does the myelin sheath function to do

Answer 17

prevent the nerve action potential from being propagated continuously along the axon

Question 18

how does action potential travel

Answer 18

by jumping from one node of ranvier to the next and so on

Question 19

what is saltatory conduction

Answer 19

the conduction pathway of action potential down myelinated axons

Question 20

what are the nodes of ranvier important for

Answer 20

action potential propagation and allowing the diffusion of nutrients and waste from and into the neuron

Question 21

what is the myelin sheath rich with

Answer 21

lipids

Question 22

what does the myelin sheath act as a barrier to

Answer 22

the diffusion of sodium ions

Question 23

where are sodium channels enrinched within the myelin sheaths of axons

Answer 23

at the nodes of ranvier

Question 24

what is endoneurium

Answer 24

loose vascular supporting tissue that surrounds each individual nerve fibre with its investing schwann cell

Question 25

what is the perineurium

Answer 25

a condensed layer of robust collagenous tissue that is invested by a layer of flat epithelial cells that surrounds each neuron fascicle

Question 26

what is the epineurium

Answer 26

loose collagenous tissue that binds the fascicles together, and is condensed peripherally to form a strong cylindrical sheath. found in peripheral nerves consisting of more than one fascicle

Question 27

what is calibre

Answer 27

the diameter of the axon

Question 28

what does greater lipid solubility of a substance enhance

Answer 28

its ability to diffuse through nerve sheaths and the neural membranes of individual axons comprising a nerve trunk

Question 29

how is lidocaine prepared

Answer 29

at 2% concentration

Question 29

what is the potency of an anaesthetic associated with

Answer 29

its lipid solubility

Question 30

how is bupivacaine prepared

Answer 30

0.5% concentration

Question 31

how do myelin sheaths appear when they are stained

Answer 31

circular

Question 32

what happens to myelin sheaths as the calibre of axons increases

Answer 32

the myelin sheaths are thicker and longer as the calibre increases

Question 33

which nervous system are motor neurons part of

Answer 33

the somatic motor system

Question 34

what do the neurons from the lumbar region of the spinal cord innervate

Answer 34

the lower limbs

Question 35

what do the neurons of the cervical region innervate

Answer 35

upper limbs

Question 36

what does ventral horn grey matter contain

Answer 36

the cell bodies of motor neurons

Question 37

how does information travel in the spinal cord for skeletal muscle innervation

Answer 37

from the central nervous system to the muscles, downwards

Question 38

which information of the spinal cord is relayed downward

Answer 38

motor innervation

Question 39

which information of the spinal cord is relayed upward

Answer 39

sensory

Question 40

what does dorsal horn matter contain

Answer 40

cell bodies of small second order sensory neurons

Question 41

what do second order sensory neurons of the dorsal horn grey matter relay

Answer 41

sensory information on pain and temperature to participate in spinal reflexes

Question 42

where are small lateral horns found

Answer 42

the thoracic and upper lumbar regions

Question 43

what do the small lateral horns of the spinal cord contain

Answer 43

cell bodies of sympathetic nervous system efferent neurons

Question 44

what are preganglionic neurons

Answer 44

sympathetic nervous system efferent neurons

Question 45

describe the structure of purkinje fibres

Answer 45

large round cell bodies with numerous branching dendrites