Peripheral Nervous System

Question 1

Describe the PNS

Answer 1

1. PNS can be divided into somatic autonomic nervous
2. Sensory (afferent) nerves carry info towards the CNS system
3. Motor (efferent) nerves carry information away from the CNA

Question 2

How many pairs of cranial nerves are there?

Answer 2

12

Question 3

How many pairs of spinal nerves are there?

Answer 3

31

Question 4

What is a plexus?

Answer 4

Collection of nerves

Question 5

What is a spinal nerve named by?

Answer 5

Has letter and number

Question 6

What is a peripheral nerve named by?

Answer 6

Has name

Question 7

What is a plexus named after?

Answer 7

Based on either where going or innervating

Question 8

What does cervical nerves go up to?

Answer 8

C1 - C8

Question 9

What does thoracic nerves go up to?

Answer 9

T1 - T12

Question 10

What do lumbar nerves go up to?

Answer 10

L1 - L5

Question 11

What do sacral nerves go up to?

Answer 11

S1 - S5

Question 12

What do coccygeal nerves go up to?

Answer 12

Co1

Question 13

Where do somatic afferent nerves covey information from?

Answer 13

Skin, skeletal muscle and joint

Question 14

Where do somatic efferent nerves convert information to?

Answer 14

Skeletal muscle

Question 15

What is a dermatome?

Answer 15

An area of skin that is supplied by a single spinal nerve

Question 16

What is a myotome?

Answer 16

Group of muscles innervated by a single spinal nerve

Question 17

Where do visceral afferent nerves carry information from?

Answer 17

the viscera (thoracic, abdominal and pelvic organs)

Question 18

What can visceral efferent nerves be divided into ?

Answer 18

• Sympathetic and parasympathetic
• Sympathetic efferent nerve innervate the viscera (organs) and periphery (vasculature and sweat glands)
• Parasympathetic efferent nerve innervate the viscera (organs) only

Question 19

What is a ganglion?

Answer 19

Collection of cell bodies outside the CNA

Question 20

What is a nucleus?

Answer 20

Collection of cell bodies inside the CNS

Question 21

What is a plexus?

Answer 21

A network of interconnecting nerves

Question 22

Where do all afferent (visceral and somatic) fibres have their cell bodies?

Answer 22

In spinal ganglia

Question 23

Where do visceral efferent nerves synapse?

Answer 23

In a peripheral ganglion

Question 24

Where is there no parasympathetic outflow to?

Answer 24

The periphery

Question 25

What are peripheral nerves arranged in ?

Answer 25

fasciculi

Question 26

What are the three layers of connective tissue?

Answer 26

1. External vascular layer - epineurium
2. Individual fascicles covered in perineurium
3. Individual axons covered in endoneurium

Question 27

What are the two classification systems of peripheral nerves?

Answer 27

1. Based on conduction velocity (A B and C with A fastest)

2. 2 Based on axonal diameter (sensory only) uses roman numeral I-IV with I the largest diameter

Question 28

What are sensory receptors?

Answer 28

• Detect external or internal information

- Can be classified as source of stimulus or by mode of detection

Question 29

What are external sensory receptors?

Answer 29

exteroceptors e.g. pain/temp/touch/pressure

Question 30

What are the different internal sensory receptors?

Answer 30

1. Proprioceptors - e.g. movement/joint position

2. Interceptors e.g. movement through gut/ blood pH

Question 31

What are chemoreceptors?

Answer 31

Detector molecules which bind to receptor, e.g. in olfactory bulb

Question 32

What are photoreceptors?

Answer 32

Detect light in retina

Question 33

What are thermoreceptors?

Answer 33

Detect temperature in skin

Question 34

Wha are mechanoreceptor?

Answer 34

Mechanical opening of ion channels e.g. touch receptors in skin

Question 35

What are nocieptors?

Answer 35

Detect tissue damage, interpreted as pain