Peripheral Nervous System

Question 1

What does the peripheral nervous system consist of?

Answer 1

Nerves (cranial and spinal) Ganglia Outside of the spinal cord

Question 2

What are the 2 major modalities of the PNS?

Answer 2

Somatic Autonomic

Question 3

What carries information towards the CNS?

Answer 3

Sensory (afferent) nerves

Question 4

What carries information away from the CNS?

Answer 4

Motor (efferent) nerves

Question 5

How many pairs of cranial nerves are there?

Answer 5

12

Question 6

How many pairs of spinal nerves are there?

Answer 6

31

Question 7

What is a plexus?

Answer 7

Area where a number of nerve fibres enter and exit under different named nerves Network of interconnecting nerves

Question 8

What is the function of somatic afferent nerves?

Answer 8

Convey information from skin, skeletal muscle and joints

Question 9

What is the function of somatic efferent nerves?

Answer 9

Convey information to skeletal muscles

Question 10

What is a dermatome?

Answer 10

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

Question 11

What is a myotome?

Answer 11

Group of muscles innervated by a single spinal nerve

Question 12

What in the function of visceral afferent nerves?

Answer 12

Carry information from the viscera

Question 13

What is the viscera comprised of?

Answer 13

Thoracic, abdominal and pelvic organs

Question 14

What can visceral efferent nerves divided into?

Answer 14

Sympathetic Parasympathetic

Question 15

What is the function of sympathetic efferent nerves?

Answer 15

Innervate the viscera and periphery

Question 16

What is the periphery comprised of?

Answer 16

Vasculature and sweat glands

Question 17

What is the function of parasympathetic efferent nerves?

Answer 17

Innervate the viscera only

Question 18

What is a ganglion?

Answer 18

Collection of cell bodies outside the CNS

Question 19

What is a nucleus?

Answer 19

Collection of cell bodies inside the CNS

Question 20

Where of afferent fibres have their cell bodies?

Answer 20

In spinal ganglia

Question 21

Where fo Visceral efferent nerves synapse?

Answer 21

In the periphery ganglion

Question 22

How are peripheral nerves arranged?

Answer 22

In fasciculi (bundles)

Question 23

What are the layers of connective tissue of a spinal nerve?

Answer 23

External vascular layer- epineurium Individual fascicles covered in -perineurium Individual axons covered in- endometrium

Question 24

How are peripheral nerves classified?

Answer 24

Two systems 1. Conduction velocity A,B,C with A the fastest 2. Axonal diameter (sensory only) I-IV with I the largest

Question 25

What is the function of sensory receptors?

Answer 25

Detect external or internal infomation

Question 26

How can sensory receptors be classified?

Answer 26

Source of stimulus Mode of detection

Question 27

How are sensory receptors further classified under source of stimulus?

Answer 27

External - Exteroceptors (pain, temperature, touch and pressure) Internal - Proprioceptors (movement and joint position) - Enteroceptors (movement through gut and blood pH)

Question 28

How are sensory receptors further classified under mode of detection?

Answer 28

Chemoreceptors Photoreceptors Thermoreceptors Mechanoreceptros Nociceptros

Question 29

What is the function of proprioceptors?

Answer 29

Muscle spindles: Detect changes in muscle length Gogli tendon organs: Detect changes in tension in tendons Joint receptors: Detect start and end of movement

Question 30

What is a neuromuscular junction?

Answer 30

Specialised synapse between a motor neurone and muscle fibre

Question 31

What is a motor unit?

Answer 31

Single lower motor neurone and all of the muscle fibres it goes to No muscle fibre is innervated by more than one nerve

Question 32

What is a reflex action?

Answer 32

Involuntary coordinated pattern of muscle contraction and relaxation elicited by peripheral stimuli

Question 33

What is the function of visceral sensory nerves?

Answer 33

Relay sensory information from the core Pain, fullness, blood pressure T1-L2, S2-S4 and cranial nerves IX and X

Question 34

What is the function of visceral motor nerves?

Answer 34

Outflow to core and body wall Controls pupil, sweat glands, salivary glands, heart muscle and airways Thoracolumbar (T1-L2) Craniosacral outflow (nerves III, VII, IX and X)

Question 35

Where do nerves going to the viscera synapse?

Answer 35

On the aorta No synapse in sympathetic trunk

Question 36

What is the branch that connects the spinal cord to other parts of the body?

Answer 36

Dorsal root ganglion

Question 37

Label parts A-D

Answer 37

A- Dorsal root B- Dorsal root ganglion C- Plexus D- Ventral root

Question 38

What must happen for all sensation from a body part to be lost?

Answer 38

Multiple nerves innervate an area All the nerves supplying a region must be damaged

Question 39

What is a dermatome?

Answer 39

A localised area of skin that is has its sensation via a single nerve from a single nerve root of the spinal cord

Question 40

Genrally, how many nerve innervate a muscle ?

Answer 40

2-3 but varies

Question 41

Give the medical terms for injuries that cause lesions at each of the indicated points

Answer 41

V and W: Strain injury or Prolapse disc Y and Z: Trauma or Peripheral neuropathy X- Trauma

Question 42

What would each of the lesions result in?

Answer 42

V: Loss of sensation W: Muscle weakness X: Loss of sensation and Muscle weakness Y: Complete loss of sensation Z: Complete loss of movement

Question 43

What is Sciatica?

Answer 43

Lumbar spinal radiculopathy

Question 44

What can cause Scaitica?

Answer 44

Nerve compression Prolapsed disc Damage to vertebrae Arthritis Piriformis syndrome

Question 45

How do you diagnose Sciatica?

Answer 45

Stretch-raise test If there is pain explore further

Question 46

How is Sciatica treated?

Answer 46

Analgesic medication e.g. Ibruprofen Physiotherapy Epidural injection to the sacral portion of the spine If it exacerbates, decompression surgery Disectomy to repostion the disc