IC3 Nervous System Part 2

Question 1

What are the 2 pathways in the somatosensory relay?

Answer 1

1. Touch pathway
2. Pain pathway

Question 2

What is the difference between the touch pathway and the pain pathway?

Answer 2

1. The touch pathway crosses the middle line only when it reaches the medulla.
2. The pain pathway crosses the middle line when it enters the spinal cord, before it reaches the medulla.

Question 3

What is hyperalgesia?

Answer 3

It is a greater than normal sensation of pain when given a noxious stimulus (e.g tissue damage)

Question 4

What is allodynia?

Answer 4

It is the sensation of pain to a normally non-painful stimulus.

Question 5

What are the 2 ways that allodynia can develop?

Answer 5

1. Damage to the inhibitory neuron
2. Hypersensitization of afferent division & 2nd order neuron
   - E.g. increase in no. of nociceptors
   - E.g. increase in no. of pain receptors on 2nd order neuron
   (2nd order neuron is the next neuron after the 1st neuron)

Question 6

What are the 2 pathways that can control pain?

Answer 6

1. Descending pathway
   a. Stress
   b. Morphine
   c. A person’s expectations & the context that the person is in
   (e.g. a soldier in a battlefield may feel less pain than in a civilised setting)
2. Segmental modulation pathway
   - Stimulation of the inhibitory neuron can decrease transmission of pain signals in the spinal cord

Question 7

What are the 3 types of movement?

Answer 7

1. Reflex - involuntary
2. Rhythmic motor patterns - require voluntary initiation & termination (e.g walking)
3. Voluntary - goal directed

Question 8

What is the role of the cerebellum

Answer 8

Aids in coordination of movement
- Any damage to the cerebellum can lead to poor coordination

Question 9

What is the role of the basal ganglia?

Answer 9

Aids via providing control in initiation & inhibition of movement.
- Any damage to the basal ganglia can lead to movement & posture disorder, E.g. Parkinsons disease