Week 6 Physiology - Nervous System

Question 1

Sensory pathways

Answer 1

Take information from outside CNS into CNS

Question 2

Types of sensors in the body

Answer 2

• Thermoreceptors - detect temperature
• Nociceptors - detect pain
• Mechanoreceptors - detect touch, pressure, vibration
• Baroreceptors - detect blood pressure
• Proprioceptors (conscious - awareness of body parts in space, unconscious - ability to maintain posture)

Question 3

Sensory receptors

Answer 3

Specialised nerve endings which monitor and respond to the environment

Question 4

Receptor transduction

Answer 4

Conversion of energy in the stimulus to an action potential

Question 5

Receptor fields

Answer 5

Relates to the density of receptors present in an area of skin that allows for discrimination

Question 6

Receptor adaptation

Answer 6

• Helps distinguish between which signals need or do not need to be sent to the brain
• Allows brain to handle constant stimulus
• Slow adapting - responds to signals that are considered to be a threat
• Rapidly adapting - responds to signals that are considered not to be a threat

Question 7

Sensory fibres

Answer 7

• Ia,II
• Ab
• A8
• C

Question 8

Ia, II afferent axon

Answer 8

Sensory function - proprioception
Receptor type - muscle spindle
Conduction velocity - 80 to 120 m/s

Question 9

Ab afferent axon

Answer 9

Sensory function - touch
Receptor type - merkel, meissner, pacinian, ruffini cells
Conduction velocity - 35 to 75 m/s

Question 10

A8 afferent axon

Answer 10

Sensory function - pain, temperature
Receptor type - free nerve endings
Conduction velocity - 5 to 30 m/s

Question 11

C afferent axon

Answer 11

Sensory function - pain, temperature, itch
Receptor type - free nerve endings (unmyelinated)
Conduction velocity - 0.5 to 2 m/s

Question 12

Sensory pathways

Answer 12

• Posterior-column meniscus pathway
• Spinothalamic pathway
• Spinocerebellar pathway
• Trigeminothalamic pathway

Question 13

Posterior-column meniscus pathway

Answer 13

Decussation region - medulla
Order of neurons - 3
Information conducted - touch, pressure, vibration, proprioception (conscious)

Question 14

Spinothalamic pathway

Answer 14

Decussation region - spinal segment
Order of neurons - 3
Information conducted - pain and temperature, tickle and itch

Question 15

Spinocerebellar pathway

Answer 15

Decussation region - no decussation
Order of neurons - 2
Information conducted - proprioception (unconscious)

Question 16

Trigeminothalamic pathway

Answer 16

Decussation region - medulla or pons
Order of neurons - 3
Information conducted - specific to face: pain, pressure, vibration, pain, temperature, tickle, itch

Question 17

Autonomic nervous system pathways

Answer 17

P - parasympathetic div
A - Acetylcholine (Ach)
M - muscarinic receptors

S - sympathetic div
N - Norepinephrine (NE)
A - alpha
B - beta (adrenergic receptors)

S - skeletal
M - muscle
A - Acetylcholine (Ach)
N - nicotinic receptors