Organisation of the NS

Question 1

What are the two divisions of the NS

Answer 1

Central Nervous System

Peripheral Nervous System

Question 2

What does the CNS consist of?

Answer 2

nerve cell bodies, axons and supporting cells

Question 3

What does the PNS consist of?

Answer 3

axons, ganglia and supporting cells

Question 4

what are the two types of cell in neural tissue

Answer 4

neurons/nerve cells and neuroglia

Question 5

what are the properties of neurons?

Answer 5

• highly differentiated
• have almost no capacity for cell division
• limited capacity to repair themselves after injury
  longest cells in the body may reach over a metre in length

Question 6

what is the function of neurons

Answer 6

transit electrical impulses along their cell membranes

Question 7

what is the function of neuroglia

Answer 7

responsible for supporting the neuron, regulating the interstitial fluid bringing nutrients

Question 8

what is the structure of a neuron

Answer 8

• cell body which contain numerous dendrites which are highly branched
• axon extends from cell body and terminated in one or more synaptic terminals where the neuron comes into contact with another cell

Question 9

In the PNS where are the cell bodies found

Answer 9

in the ganglia and supported by satellite cells

Question 10

what are the axons supported by

Answer 10

schwaan cells which either myelinate a section up to 1mm in length or a few axons are enclosed within the schwan cell

Question 11

what are most cell bodies in the CNS protected by

Answer 11

cranium and vertebral column

Question 12

what do axons do in CNS and PNS

Answer 12

CNS - leave to supply motor fibres to muscles (both skeletal and smooth) and collect sensory info
PNS - axons are collected together into bundles called nerves

Question 13

what are the subdivisions of the PNS

Answer 13

somatic nerves
nerves of special sensation
autonomic nerves

Question 14

what do somatic nerves supply

Answer 14

body wall. skeletal muscle and skin

- contain both motor and sensory fibres

Question 15

what do autonomic nerves supply

Answer 15

internal organs with motor and sensory fibres

Question 16

where do all sensory axons have their cell bodies

Answer 16

outside the CNS in ganglia where there are no snapses

Question 17

where do all motor ganglia belong?

Answer 17

to the ANS and always contain synapses

Question 18

names of somatic nerves and their derivation

Answer 18

referred to as spinal nerves if they originate from the spinal cord
- cranial nerves if they arise from the brain

Question 19

what is a dermatome?

Answer 19

areas of the skin that are mainly supplied by a single spinal nerve

Question 20

where do sensory fibres travel?

Answer 20

for the most part in company with the motor fibres

Question 21

where do sensory fibres have their ganglia

Answer 21

posterior root ganglia of the spinal nerves or in the sensory ganglia of the cranial nerves

Question 22

what do motor fibres do

Answer 22

innervate smooth muscle and glands , for the most part directly but in the GI tract they modulate activity of its AS

Question 23

what would strong sympathetic activity lead to

Answer 23

staring eyes, cold clammy skin, dry mouth, hair standing on end, sinking feeling in stomach

Question 24

where does sympathetic NS arise

Answer 24

T1-L2

Question 25

where does parasympathetic NS arise

Answer 25

cranio sacral
cranial nerves III, VII, IX and X
sacral spinal nerve S2-4
in head and trunk only