Somatic sensation

Question 1

special senses

Answer 1

• vision
• hearing
• balance
• taste
• smell

Question 2

somatic senses

Answer 2

• mechanoreceptors: touch, pressure, vibration, proprioception
• nociceptors: noxious stimuli (pain)
• thermoreceptors: temperature
• chemoreceptors: chemicals (e.g. blood gases)
• receptors distributed throughout the body

Question 3

signal transduction
1
sensory … have a specialisation that makes them sensitive to a particular …

Answer 3

receptors, stimulus

Question 4

signal transduction
2
presentation of the stimulus … ion channels which leads to a change in … potential, a … potential

Answer 4

opens, membrane, receptor

Question 5

signal transduction
3
if the … reaches threshold, an … is initiated in the … …

Answer 5

RP, AP, sensory axon

Question 6

mechanoreceptors
proprioception and touch
are?

Answer 6

stimulated by physical forces that distort the plasma membrane. nerve endings contain mechanically gated ion channels

Question 7

mechanoreceptors

3 kinds of mechanically gated ion channels

Answer 7

proprioceptors
baroreceptors
tactile receptors = touch, pressure, vibration

Question 8

why are mechanosensitive receptors in our skin mechanosensitive?

Answer 8

because they have a specialisation that allows them to respond to some aspect of touch, some are very superficial and some are deeper

Question 9

skin thermoreceptors and nociceptors

are?

Answer 9

free nerve endings, typically classified by type of axon (3 types)

Question 10

2 types of axons in skin thermoreceptors and nociceptors

Answer 10

myelinated axons = temperature (usually change in temp)

unmyelinated or thinly myelinated axons = sensations typically perceived as painful

Question 11

receptive field

is?

Answer 11

endings of any single receptor spread over a restricted area

Question 12

receptive field

sensory neuron is only stimulated when?

Answer 12

the stimulus is presented within the area it’s receptors are located, the recptive field

Question 13

receptive field

does a bigger or smaller field provide better localisation?

Answer 13

smaller as you can distinct more sources of touch

Question 14

tonic receptors

Answer 14

continually active to reflect background level of stimulation. AP frequency changes when stimulus intensity changes e.g. muscle spindles. slowly adapting

Question 15

phasic receptors

Answer 15

normally silent, respond briefly to change, e.g. touch and temperature receptors
fast adapting

Question 16

4 types of information encoded in sensory stimuli

Answer 16

modality
intensity
duration
location

Question 17

modality

Answer 17

type of receptor activated e.g. temperature, touch

Question 18

intensity

Answer 18

stimulus strength, encoded by frequency of action potential firing in afferent neuron, and number of afferent axons activated

Question 19

duration

Answer 19

time period over which stimulus exists encoded by time period over which action potentials are fired (or over which pattern of firing changes) in afferent neuron

Question 20

location

Answer 20

place in body where receptors are activated, ‘mapped’ in brain (somatosensory cortex)