Sensory and Motor Information

Question 1

What is the function of the somatosensory system?

Answer 1

tells us what the body is doing and what is going on in the environment

Question 2

What are the two types of skin?

Answer 2

hairy and glabrous

Question 3

What is the function of hairy skin?

Answer 3

a low sensitivity type of skin

Question 4

What is the function of glabrous skin?

Answer 4

a hairless skin which has many sensory receptors

Question 5

What do nociceptors do?

Answer 5

perceive pain and temperature via free nerve endings

Question 6

How to nociceptors work?

Answer 6

damage to the dendrite or surrounding cells causes the release of prostaglandin which stimulates the dendrite and produces an action potential

Question 7

How do pain killers work?

Answer 7

block the synthesis of prostaglandin

Question 8

What do haptic receptors do?

Answer 8

perceive fine touch or pressure and is able to distinguish touch, pull, vibration, flutter and indentation

Question 9

How do haptic receptors work?

Answer 9

the mechanical stimulation of a hair produces an action potential

Question 10

What do Merkel’s receptors do?

Answer 10

transmit information about steady skin indentation

Question 11

What do Meissner’s corpuscles do?

Answer 11

perceive light touch

Question 12

What do Ruffini’s corpuscles do?

Answer 12

perceive steady skin indentation

Question 13

What do Pacinian corpuscles do?

Answer 13

perceive vibration and deeper pressure

Question 14

What is proprioception?

Answer 14

the perception of the location and movement of the body

Question 15

How is proprioception perceived?

Answer 15

movements stretch the receptors to mechanically stimulate dendrites and produces an action potential

Question 16

What detects a muscle stretch?

Answer 16

muscle spindles

Question 17

What detects a tendon stretch?

Answer 17

golgi tendon organs

Question 18

What detects joint movement?

Answer 18

joint receptors

Question 19

How do rapidly adapting receptors work?

Answer 19

receptors briefly respond to the beginning and end of a stimulus on a body

Question 20

What are the benefits of rapidly adapting receptors?

Answer 20

gives a good response to repeated stimuli

Question 21

How do slowly adapting receptors work?

Answer 21

receptors respond as long as a sensory stimulus is on the body

Question 22

What are the benefits of slowly adapting receptors?

Answer 22

good for detecting painful stimulus which is beneficial for evolutionary reasons

Question 23

Describe the axons of nociceptive neurons

Answer 23

Small with little or no myelination (slow)

Question 24

Describe the axons of proprioceptive and haptic neurons

Answer 24

large, well myelinated axons (fast)

Question 25

Describe deafferentiation

Answer 25

loss of incoming sensory input usually due to damage to sensory nerve fibres

Question 26

What are some effects of deafferentiation?

Answer 26

motor control is not lost but some actions would require visual feedback, daily tasks could not be performed and afferent feedback is required for fine movements

Question 27

What does the dorsal spinothalamic tract do?

Answer 27

carries haptic and proprioceptive information

Question 28

How is information carried along the dorsal spinothalamic tract?

Answer 28

axons from the dorsal-root ganglion neuron enter the spinal cord and ascend ipsilaterally to synapse in the dorsal column nuclei

Question 29

What does the ventral spinothalamic tract do?

Answer 29

carries nociceptive information

Question 30

How is information carried along the ventral spinothalamic tract?

Answer 30

axons from the contralateral spinal cord ascend to the brain

Question 31

What is a monosynaptic reflex?

Answer 31

a reflex requiring one synapse between sensory input and movement e.g. knee jerk

Question 32

What does the vestibular system do?

Answer 32

responds to body position and movement of the head in relation to gravity

Question 33

What does the vestibular system consist of?

Answer 33

three semicircular canals and otolith organs (utricle and saccule)

Question 34

How is head movement detected?

Answer 34

endolymph fluid located in the semicircular canals pushes against hair cells bending the cilia creating action potentials

Question 35

How does the direction in which the cilia are bent affect the potential?

Answer 35

the direction will create depolarisation or hyperpolarisation

Question 36

How is acceleration detected?

Answer 36

the utricle and saccule contain hair cells embedded in a gelatinous substances which are pushed on my otoconia altering the rate of action potentials

Question 37

What is otoconia?

Answer 37

small crystals of calcium carbonate in the utricle and saccule

Question 38

What is the function of the primary somatosensory cortex?

Answer 38

receives projections from the thalamus and begins the process of constructing perceptions from somatosensory information

Question 39

What is the function of the secondary somatosensory cortex?

Answer 39

located behind the primary somatosensory cortex, it continues the construction of perceptions projecting to the frontal cortex

Question 40

What did Wilder Penfield research?

Answer 40

the effects of stimulation on the cortical surface of the brain using electrodes

Question 41

What did Jon Kaas research?

Answer 41

developed Enfield’s work and used smaller electrodes to more precisely locate the functional layout of the cortex