Sensory Receptors & Sensory Coding

Question 1

Mention functions of sensory receptors

Answer 1

Detectors of stimuli
Transducers produce generator potential
Generators: generate action potential in affrent nerves
Inform CNS about changes in internal & external environment

Question 2

Mention properties of sensory receptors & corresponding law if present)

Answer 2

Specificity (Muller’s law)
Excitability (generator potential)
Dischange of impulse (Weber-Fechner’s law)
Adaptation

Question 3

State Weber-Fechner law

Answer 3

Generate potential in afferent neurons in a frequency proportional to log stimulus intesity

Question 4

Mechanism of receptor adaptation

Answer 4

Readjustment, as the fluid is redistributed & receptor potential is no longer elicited
Accomodation due to progressive inactivation of Na channels

Question 5

Describe mechanism of modality discrimination

Answer 5

Type of receptor stimulated
Pathway activated when stimulus is applied to receptor
“Labelled-line principle”

Question 6

…….helps CNS to localize a stimulus

Answer 6

Lateral inhibition

Question 7

Explain phantom limb phenomenon

Answer 7

It is explained by that the nerves remaining in the stump can form nodules called neuromas which can generate impulses to the brain interpreted as arising from the limb.

Question 8

Mention factors of discrimination of:
1. Intesity
2. Duration

Answer 8

Frequency of action potentials, number of receptors stimulated.
Ability of receptor to adapt slowly or rapidly

Question 9

Classify receptors acconding to adaptation with giving examples

Answer 9

Rapidly adapting, touch receotirs
Moderately adapting, thermoreceptors
Slowly adapting, pain receptors