Peripheral nervous system

Question 1

What is the peripheral nervous system divided into?

Answer 1

Somatic and autonomic nervous systems

Question 2

Which neurones transmit information towards the CNS?

Answer 2

Sensory afferent nerves

Question 3

Which neurones transmit information away from the CNS?

Answer 3

Motor efferent nerves

Question 4

How many pairs of spinal nerves are there?

Answer 4

31

Question 5

What is a neural plexus?

Answer 5

Derived from multiple spinal cord segments, and is an intricate network of nerves

Question 6

Describe the nomenclature of peripheral and spinal nerves:

Answer 6

Peripheral nerves are allocated a name

Spinal nerves are enumerated with a corresponding letter

Question 7

Which layer sheaths the entire nerve?

Answer 7

Epineurium

Question 8

Which layer surrounds the bundles of nerve fibres?

Answer 8

Perineurium

Question 9

Which layer is intermediate of individual nerve fibres?

Answer 9

Endoneurium

Question 10

Which meningeal layer is continuous with the epineurium?

Answer 10

Dura mater

Question 11

Which two meningeal layers are continuous with the endoneurium and the perineurium?

Answer 11

Pia mater and the arachnoid layer

Question 12

What is a dermatome?

Answer 12

An area of skin that is supplied by a single spinal nerve (strips of skin consists of a single nerve)

Question 13

What is a myotome?

Answer 13

Group of muscles innervated by a single spinal nerve

Question 14

What nerves conduct sensory impulses from the viscera?

Answer 14

Visceral afferent nerves

Question 15

Do parasympathetic efferent nerves innervate the blood?

Answer 15

No

Question 16

Which structure contains multiple cell bodies existing outside the CNS?

Answer 16

Ganglia

Question 17

Which structure contains a collection of cell bodies inside the CNS?

Answer 17

Nucleus

Question 18

Where are afferent somatic and visceral fibre cell bodies?

Answer 18

Reside within spinal ganglia

Question 19

Which nerve fibres synapse with the peripheral ganglion?

Answer 19

Peripheral nerves

Question 20

How are peripheral nerves arranged?

Answer 20

Bundled in fasciuli, comprised of three connective tissue layres: (Epineurium, perineurium, and endoneurium)

Question 21

Which layer sheaths individual fasicules?

Answer 21

Perineurium

Question 22

Which layer sheaths individual axons?

Answer 22

Endoneurium

Question 23

What two parameters are used to classify peripheral nerves?

Answer 23

Based on conduction velocity

Based on axonal diameter

Question 24

What classification system is used to classify nerves based on conduction velocity?

Answer 24

Letters (ABC)

A- fastest

Question 25

Which classification system is used to classify nerves based on axonal diameters?

Answer 25

``` Roman numerals (I-IV) 1 fastest ```

Question 26

Which nerves are classified under the axonal diameter system?

Answer 26

Sensory nerves exclusively

Question 27

What effect does myelination have on conduction velocity?

Answer 27

Increases conduction velocity due to the principle of saltatory conduction

Question 28

What are exteroceptors

Answer 28

Detect pain, touch, pressure and temperature

Question 29

Which receptors detect movement and joint position?

Answer 29

Proprioceptors

Question 30

Which receptors detect the internal environment (Blood pH,and gastrointestinal movement)?

Answer 30

Enteroceptors

Question 31

What are chemoreceptors?

Answer 31

Specialised sensory receptors transduce a chemical substance and subsequently generates an electrical signal

Question 32

Where are chemoreceptors located?

Answer 32

Medulla = environmental pH Peripheral= Aortic arch and carotid sinus Olfactory bulb

Question 33

Which receptors detect light in retina (rods and cones)?

Answer 33

Photoreceptors

Question 34

What are mechanoreceptors?

Answer 34

Detects opening of ion channels

Question 35

What are nociceptors?

Answer 35

Detects signals from damaged tissue or threat of damage indirectly respond to chemicals released from damage tissue

Question 36

Which proprioceptor in muscle detect changes in length?

Answer 36

Muscle spindles

Question 37

What happens during muscle stretch in terms of electrical transmission? (reflex)

Answer 37

Stimulates reflexively, a muscle contraction to counteract overstretching and muscle fibre damage (Myotatic reflex) Stretching causes the muscle fibre to transmit an electrical impulse to the spinal cord to stimulate a muscular response.

Question 38

What is the static component of myotatic reflex?

Answer 38

Persists during the time of muscular stretch

Question 39

What is the dynamic component of the myotatic reflex?

Answer 39

Lasts momentarily in response to the initial sudden increase in muscle length

Question 40

Which proprioceptor detects changes in tension in tendons?

Answer 40

Golgi tendon organs

Question 41

Which neurotransmitter is released at an inhibitory interneuron?

Answer 41

Glycine, hyperpolarises motor neurone, causes muscle to relax

Question 42

What is a neuromuscular junction?

Answer 42

Specialized synapse between a motor neuron and a muscle fibre Motor neurone axon approaches innervated muscle

Question 43

What is a motor unit?

Answer 43

Single motor neurone in conjunction with corresponding muscle fibres that it innervates. Smallest functional unit to produce force

Question 44

What is a motor pool?

Answer 44

Collection of motor neurones collectively coordinate together to stimulate contractions of a single muscle, all of the motor units within a muscle is considered as a motor pool.

Question 45

Where do sympathetic neurones arise?

Answer 45

Thoracolumbar

Question 46

What effects does sympathetic innervation have on the body?

Answer 46

Direct blood to muscles, dilation of pupils, increases respiratory rate, dilation of airways, increased heart rate

Question 47

What effect does parasympathetic innervation have?

Answer 47

Rest, increased gastric secretions decreased respiratory and heart rate

Question 48

Where do preganglionic efferent axons leave the spinal cord?

Answer 48

Through the ventral nerve roots joining the mixed spinal nerve

Question 49

How do preganglionic sympathetic fibres enter the sympathetic chain of ganglia?

Answer 49

Through the white ramus communicans

Question 50

What do paravertebral trunks contain?

Answer 50

Post-ganglionic neurone cell bodies

Question 51

Fibres concerned with innervation of structures in the head and thorax terminate where?

Answer 51

Terminate in synaptic contact with postganglionic celll bodies in the sympathetic chain

Question 52

Fibres concerned with innervation of structures of pelvic and abdominal viscera terminate where?

Answer 52

Pass uninterrupted through the sympathetic chain and travel to plexuses

Question 53

What does the mixed spinal nerve contain?

Answer 53

Mixed spinal nerve contains pre and post-ganglionic fibres. Synapse, postganglionic neurone can ascend or descend

Question 54

Where do postganglionic nerve fibres leave the sympathetic chan?

Answer 54

Gray ramus communicans

Question 55

Why is the gray ramus communicans gray?

Answer 55

Unmyelinated