Classification of the Nervous System

Question 1

what are the ways to subdivide the nervous system?

Answer 1

into:
topographical subdivisions
functional subdivisions
directional subdivisions

Question 2

what are the topographical subdivisions?

Answer 2

Central nervous system (brain and spinal cord)
and
Peripheral nervous system (cranial and spinal nerves)

Question 3

what are the functional subdivisions?

Answer 3

Somatic system (voluntary)
Visceral system (involuntary) incl. Autonomic nervous system further subdivided into –> sympathetic and parasympathetic

Question 4

what are the directional subdivisions?

Answer 4

Afferent = towards brain and spinal cord
Efferent = away from brain and spinal cord

Question 5

inside the head, the neural tube expands and develops into three main regions, what are these?

Answer 5

The prosencephalon (forebrain)
The mesencephalon (midbrain)
The rhombencephalon (hind brain)

Question 6

what is the prosencephalon divided into?

Answer 6

telencephalon
diencephalon

Question 7

what is the rhombencephalon divided into?

Answer 7

metencephalon
myelencephalon

Question 8

etmology - telecephalon?

Answer 8

tele - far away
cephalon - brain

Question 9

di?

Answer 9

diaganol

Question 10

mye?

Answer 10

marrow or medulla - implies inside

Question 11

encephalon means?

Answer 11

brain

Question 12

mesos?

Answer 12

middle

Question 13

meta?

Answer 13

beside

Question 14

olfactory bulb?

Answer 14

part of the brain that deals with sense of smell

Question 15

peripheral nervous system made up of?

Answer 15

cranial nerves
spinal nerves
ganglia (cell bodies): sensory, autonomic motor

Question 16

how is myelination achieved in the PNS?

Answer 16

a separate Schwann cell

Question 17

how is myelination achieved in the CNS?

Answer 17

arms of a myelin-forming oligodendrocyte

Question 18

what is the advantage of myelination?

Answer 18

myelination speeds up action potential velocity
enhances speed of induction

Question 19

axons originating in the brain and travelling down the spinal cord?

Answer 19

tracts

Question 20

nerves called what in CNS?

Answer 20

in CNS, bundles of neurone axons are ‘tracts’
whereas in PNS they are known as ‘nerves’ by definition

Question 21

what is functional classification due to?

Answer 21

the nervous system can be functionally divided on the direction of nerve transmission

Question 22

afferent - functional classification?

Answer 22

towards spinal cord or specific brain regions
Afferent are Arriving nerve axons
Within spinal cord, can be called ascending
Sometimes also termed ‘sensory’

Question 23

efferent - functional classification?

Answer 23

away from spinal cord or specific brain regions
Efferent are Exiting nerve axons
Within spinal cord, can be called descending
Sometimes also termed ‘motor’

Question 24

as well as general afferent and efferent components - there is also special afferent, what is this?

Answer 24

concerned with special senses (taste and smell, vision, hearing and balance)

Question 25

Somatic - is the voluntary nervous system, describe it?

Answer 25

senses and controls body relative to external environment - sensory perceptions (touch, pressure, heat, pain, proprioception) special senses (vision, balance, hearing) Motor neurones to skeletal muscles (upper and lower motor neurones) Related ascending and descending pathways in the CNS

Question 26

What do Upper motor neurones (UMN) do?

Answer 26

initiate voluntary movements, regulate muscle tone

Question 27

What do Lower motor neurones (LMN) do?

Answer 27

directly control muscle contraction

Question 28

nerve paralysis - UMN stopped working but LMN still working?

Answer 28

the muscle will still work but there is no control over it and the muscle reaction can be really exaggerated

Question 29

Visceral - involuntary nervous system?

Answer 29

senses and maintains the internal environment within permissible limits Sensing internal environment (receptors in organs and blood vessels) Special senses (taste and smell) Adjusting internal environment through innervation of organs (the Autonomic nervous system) Hypothalamus = an important integration centre Hypophysis (pituitary gland) also produces + stores important hormones

Question 30

facial nerve for example - classification?

Answer 30

visceral function due to taste and submandibular salivary gland also somatic function as it helps with movement of facial muscles

Question 31

somatic?

Answer 31

deals with pain

Question 32

visceral?

Answer 32

sensing stretch receptors in intestines etc

Question 33

somatic?

Answer 33

voluntary nervous system

Question 34

visceral?

Answer 34

involuntary nervous system