Sensory System

Question 1

Receptor as specialized ending of a nerve cell

Answer 1

The receptor is part of the neuron, so when the receptor potential is produced, action potential will be fired in the same neuron

Question 2

Receptor as a specialized cell in its own right

Answer 2

The receptor is in a specialized receptor cell which is located near the neuron. When the receptor potential is produced, the receptor potential modulates transmitter release from the receptor to the neuron leading to action potential in that neuron

Question 3

Afferents that have ___________ endings generally have lower thresholds for action potential generation

Answer 3

Encapsulated

Question 4

Which afferents fibers endings are more sensitive to sensory stimulation?

Answer 4

Encapsulated endings

Question 5

Nerve fibers are classified according to ….?

Answer 5

Axon diameter

Presence of myelination

Question 6

What determines the conduction velocity?

Answer 6

Axon diameter

Presence of myelination

Question 7

What’s sensory coding?

Answer 7

Converting a sensory stimulus to a recognizable sensation

Question 8

Coding for type of stimulus (modality)

Answer 8

Type of activated receptor
Specific pathways that convey the stimulus
Particular area of the cortex

Question 9

Coding for stimulus intensity

Answer 9

Frequency of action potential

Recruitment (activation of more than one neuron)

Question 10

In population coding, recruitment is

Answer 10

Stronger stimulus activates more receptors on the same afferent (summation) and/or other afferents

Question 11

In coding for intensity, activating each receptor more is…

Answer 11

As stimulus intensity increases, a receptor sensitive to that stimulus will respond more strongly by opening more ion channels and activating more molecules, this will produce a larger change in the ionic movement & a larger change in resting membrane potential, leading to producing larger receptor potential.

Question 12

In coding for intensity, activating more neurons is ..

Answer 12

At a low stimulus level, only the most sensitive neurons are activated
As stimulus intensity increases, the most sensitive neurons respond more strongly and then the next most sensitive neuron gets activated

Question 13

In coding for quality..

Answer 13

The full range of a stimulus modality is divided up between different receptors. Each receptor is tuned to only a part of the full stimulus range.

Question 14

Adaptation is

Answer 14

Decrease in the responsiveness despite a constant stimulus

Question 15

Example of slow adaptive receptors

Answer 15

Merkel cells

Ruffini endings

Question 16

Example of rapid adaptive receptors

Answer 16

Meissner’s corpuscle

Pacinian corpuscle