W6 - Sensory Input

Question 1

Why are the 5 classic senses not well considered in physiology?

Answer 1

Some of these senses measure the same or multiple different stimuli (e.g. touch - pressure, temp and damage and hearing + taste - both chemical stimuli)

Question 2

What is the definition of signal transduction?

Answer 2

The conversion of environmental factors into neural information (APs)

Question 3

What are the 5 modalities?

Answer 3

Mechanoreception, thermoreception, photoreception, chemoreception and nociception

Question 4

What are the 5 types of mechanoreception?

Answer 4

Pressure, body positioning, sound, acceleration and gravity

Question 5

What does thermoreceptors detect? (e.g. sensors in HT, free nerve endings in skin)

Answer 5

Temperature

Question 6

What do photoreceptors detect? (e.g. rod and cone cells)

Answer 6

Electromagnetic waves

Question 7

What do chemoreceptors detect? (e.g. olfactory/gustatory receptors)

Answer 7

Specific chemicals

Question 8

What does nociception detect? (NK1 receptors for substance P)

Answer 8

Cellular damage

Question 9

Describe the two ways neurons are stimulated?

Answer 9

Directly - stimulus depolarises afferent neuron directly, Indirect - sensory cell (e.g. epithelial cell) is stimulated to release NTMs that stimulate the afferent neuron

Question 10

What do pacinian corpuscles detect?

Answer 10

Vibration

Question 11

Pressure in the form of high frequency waves deform the lamella and the dendrite, how does this cause depolarisation?

Answer 11

Opens stretch mediated Na+ channels

Question 12

What 2 things do muscle spindles respond to and tell the brain of?

Answer 12

Muscle length and rate of change of length

Question 13

Are pacinian corpuscles and muscle spindles directly or indirectly stimulated?

Answer 13

Directly

Question 14

Hair cells are modified epithelial cells that help in hearing, what is the kinocilium and what does this link to?

Answer 14

Kinocilium - tallest cilium, links to stereocilium

Question 15

When the kinocilium bends away/towards the stereocilia what happens?

Answer 15

Away from - K+ channels open, Towards - K+ channels closed

Question 16

What is it that causes the movement of kinocilia?

Answer 16

Sound waves vibrate the tectorial membrane that causes them to bend

Question 17

There’s canals of extracellular gel that help to detect acceleration + gravity, what do the heavy otoliths do to detect gravity when the head tilts or acceleration as you move?

Answer 17

Pulls gel down or sideways, bending the hair cells’ kinocilium

Question 18

WHen muscle spindles shorten, does the AP frequency increase or decrease?

Answer 18

Decrease

Question 19

What is the example of neurons being indirectly stimulated?

Answer 19

Hearing using modified epithelial cells (hair cells)

Question 20

Are different receptors for touch all detecting the same thing?

Answer 20

No, the receptors are sensitive to only one modality

Question 21

Stimulus location says that…

Answer 21

A sensor should be able to determine the location of the stimulus

Question 22

What happens to the APs as the stimulus intensity increses?

Answer 22

APs get more frequent as you recruit more receptors

Question 23

Tonic receptors are ???? adapting receptors that respond for the ??????????????????

Answer 23

Slowly, duration of the stimulus

Question 24

Phasic receptors are ???? adapting receptors, how do they fire APs during a constant stimulus?

Answer 24

Quickly, they fire once at the beginning of the stimulus and then switch off, then fire again when the stimulus ends

Question 25

In the somatosensory system, areas of the brain are uniquely attributed to………..

Answer 25

Certain body areas (e.g. homunculus)