week 9 - somatosensation

Question 1

What are the types of sensory receptors?

Answer 1

• nociceptors
• thermo-receptors
• mechanoreceptors
• chemoreceptors
• proprioceptors
• baroreceptors

Question 2

nociceptors

Answer 2

detect pain (overlap with mechanical, thermal, and chemical)

Question 3

thermoreceptors

Answer 3

• detect temperature
• cold/warm receptors

Question 4

mechanoreceptors

Answer 4

• constructed to detect membrane distortion
• 3 different types (tactile, discriminative, and crude)

Question 5

efferent pathways

Answer 5

conduct motor commands

Question 6

tactile receptors (mechanoreceptors)

Answer 6

detect touch, pressure, and vibrations

Question 7

What are the two main somatosensory pathways?

Answer 7

• dorsal column pathway
• spinothalamic tract

Question 8

dorsal column pathway

Answer 8

primary carries sensations of touch, vibrations, and propriception

Question 9

spinothalamic tract/anterolateral pathway

Answer 9

carries information regarding temperature and pain

Question 10

chemoreceptors

Answer 10

• detect concentration of specific chemicals/compounds
• play a role in maintaining homeostasis

Question 11

proprioceptors

Answer 11

allow us to detect positions of joint and muscles

Question 12

baroreceptors

Answer 12

detect pressure changes deep in our body

Question 13

Describe how receptive fields work and how stimuli in overlapping receptive fields are perceived.

Answer 13

• skin contains receptor fields, and the area they cover all vary in size.
• smaller receptive fields will be closer together, which makes it easier to detect change and localize a stimulus.
• larger receptive fields do not detect changes as quick, which is why it is harder to localize a stimulus

Question 14

tonic receptors

Answer 14

• always active
• detect the level of stimulation
• monitor background levels

Question 15

phasic receptors

Answer 15

• detect change in stimulation
• become active for a short time whenever change occurs
• monitors intensity and rate of change of stimulus

Question 16

afferent pathways (sensations)

Answer 16

• responsible for sensing information at the skin/muscle
• detected by sensory receptors

Question 17

describe how the somatosensory homunculus affects perception of bodily sensation

Answer 17

• representation of the human body within the somatosensory cortex of the brain
• cortical map illustrates the relative proportions of different body parts, with larger areas dedicated to regions that are more sensitive
• more cortical processing to hands and lips -> better sensory discrimination