Sensation

Question 1

Define:
1. Sensory unit
2. Receptive field

Answer 1

1. Single sensory axon and all its peripheral branches that vary in number
2. Spatial dustribution from which a stimulus produces a response in that unit. It differs from one area to another allover the body.

Question 2

Mention classifications of sensations

Answer 2

Site, type, localization, ascending sensory pathway

Question 3

Mention the mixed sensations

Answer 3

Vibration
Stereognosis

Question 4

Mention the thalamic sensations

Answer 4

Slow pain
Crude tough
Wide degrees of thermal variation

Question 5

Classify sensations according to ascending sensory pathway

Answer 5

Spinothalamic, thermal, crude touch, pain, itch & tickle, sexual sensations
Dorsal column, fine touch , stereognosis, vibration, proprioception, deep pain

Question 6

Define crude touch, tickle & itch

Answer 6

1. The ability of body to detect contact with objects
2. Local repeated mechanical stimulation of cutaneous receptors by light moving objects
3. Sensation of irritation caused by chemicals (histamine & kinins) that lead to scratch reflex

Question 7

Higher nervous perception site for crude touch & itch & tickle

Answer 7

Thalamus

Question 8

Higher nervous perception site for thermal senstaions

Answer 8

Thalamus & sensory cortex

Question 9

Receptors for crude touch & itch & tickle & thermal sensations

Answer 9

All are FNE ex cold which is FNE & Krause end bulb & crude touch also hair end organ.

Question 10

Adaptation for crude touch & thermal s.

Answer 10

1. Rapid
2. Moderate but hot is faster

Question 11

How to examine for crude touch & thermal

Answer 11

Cotton wool test
Two test tube test

Question 12

Mechanism of stimulation of thermal sensations

Answer 12

Changes in conc of metabolites in thermoreceptors that activate or inactivates ion channels
Excess change in temp activate transient receptor potential Which are also ion channels

Question 13

Cold spots are more numerous tyan hot spots by

Answer 13

3-10 times

Question 14

Thermoreceptors are more numberous in …than ….than.l.l

Answer 14

Lips, hand, trunk