Peripheral nervous system

Question 1

Somatic afferent nerves convey information from?

Answer 1

Skin, Skeletal muscle and joints

Question 2

Somatic efferent nerves convey information to ?

Answer 2

Skeletal muscles

Question 3

What is a Dermatome

Answer 3

An area of skin supplied by a single spinal nerve

Question 4

What is a myotome?

Answer 4

Group of muscles innervated by a single spinal nerve

Question 5

What is the difference between what sympathetic and parasympathetic efferent nerves innervate?

Answer 5

Sympathetic - viscera and periphery (vasculature and sweat glands)

parasympathetic - viscera only

Question 6

What is a plexus?

Answer 6

A network of interconnecting nerves

Question 7

All afferent fibres have their cell bodies in?

Answer 7

Spinal ganglia

Question 8

Visceral efferent nerves synapse in a?

Answer 8

Peripheral ganglion

Question 9

Peripheral nerves structure?

Answer 9

Arranged in fasciculi
Three layers of connective tissues
Epineurium - external vascular layer
Perineurium - indivitual fascicles covered by it
Endoneurium - covers individual axons

Question 10

What are the two classification systems of peripheral nerves?

Answer 10

1. Conduction velocity: A being the fastest - B, C etc

2. Axonal diameter (sensory only) use roman numerals, I being largest diameter

Question 11

Exteroceptors stimuli?

Answer 11

Pain, temp, touch, pressure

Question 12

Proprioceptors stimuli?

Answer 12

Movement, Joint, Position

Question 13

Enteroceptors stimuli?

Answer 13

Movement through gut, blood pH

Question 14

Sensory receptors which are classified by mode of detection?

Answer 14

Chemoreceptors (detector molecules which bind to receptor)
Photoreceptors
Thermoreceptors
Mechanoreceptors (touch opening ion channels)
Nociceptors (tissue damage - pain)

Question 15

Three examples of proprioceptors?

Answer 15

Muscle spindles: detect muscle length change

Golgi tendon organs: detect tension in tendons

Joint receptors: in joint capsules, detect start and end of movement

Question 16

What is the smallest functional unit with which to produce force?

Answer 16

A single motor neurone together with all its muscle fibres it innervates (600 muscle fibres)

Question 17

What is a reflex action?

Answer 17

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

Question 18

Are there exceptions to the rule that the sympathetic system releases noradrenaline at post ganglionic neurons?

Answer 18

Sweat glands ands blood vessels - acetylcholine is Nt released

Question 19

Which nerves are a part of the visceral sensory system?

Answer 19

T1-L2, S2-S4, cranial nerves IX and X

Question 20

Which nerves are a part of the visceral motor system?

Answer 20

Thoracolumbar T1-L2 and craniosacral outflow - Cranial nerves III, VII, IX, X

controls pupils, sweat glands, heart muscles, airways

Question 21

Where do sympathetic nerves not emerge from?

Answer 21

Cervical cord or low lumbar cord.

come out from thoracic and lumber cord - T1 to L2

Question 22

What is the lateral horn?

Answer 22

lateral projection of grey matter between the dorsal and ventral horn. contains the neuronal cell bodies of the sympathetic nervous system.

Question 23

What are paravertebral sympathetic chains?

Answer 23

Run either side of the vertebral column

Question 24

What is the White ramus communicas?

Answer 24

(white due to its colour as it contains preganglionic neurones which have myelin sheaths) It is a structure that anteriorly connects spinal nerve to sympathetic trunk.

Question 25

What is they Grey ramus communicas?

Answer 25

When the post ganglionic nerve goes back to the mixed spinal nerve it goes through the grey ramus communicas branch.

Question 26

What are the nerves surrounding the heart called?

Answer 26

Cardiac plexus, emerging from thoracic segment T1 to T4

Question 27

The sympathetic nerves can innervate the periphery and the viscera

Where do the neurones for each type synapse?

Answer 27

Visceral : There are no synapses in the sympathetic trunk, they synapse in the pre-aortic ganglia.

compared to sympathetic output to periphery:
these pre-ganglionic nerves can travel through chains and synapse at different levels.

Question 28

What are splanchnic nerves?

Answer 28

preganglionic nerves go straight to gut through splanchnic nerves. Form greater, lesser and least splanchnic nerves.