Lec 8: Sensory receptors

Question 1

sensory receptor

Answer 1

convert a stimulus into an electrical signal (action potential)

Question 2

sensory pathways

Answer 2

convey sensory info from peripheral and central NS

Question 3

Sensory processing

Answer 3

CNS

Question 4

Cranial nerves

Answer 4

C1-C8

Question 5

Thoracic nerves

Answer 5

T1-12

Question 6

Lumbar nerves

Answer 6

L1-5

Question 7

Sacral nerves

Answer 7

S1-5

Question 8

Coccygeal nerves

Answer 8

CO1

Question 9

Dermatome

Answer 9

An area of skin that is mainly supplied by a single spinal nerve which relays sensation from the skin to the brain

Question 10

Somatotopy (brain body picture)

Answer 10

the correspondence of an area of the body where sensory info arise to a specific point in the brain where this info is processed

Question 11

Somatosensory

Answer 11

info relayed from receptor in skin, body surface, muscles and joints. (controls voluntary movements of skeletal muscle

Question 12

Viscerosensory

Answer 12

info relayed from receptors mainoy in visceral organs (incl. blood vessels) (influences autonomic - unconscious- regulation of these organs

Question 13

(location) Primary vs seconday (and tertiary) afferent neuron

Answer 13

Primary - part of PNS, found in ganglia of cranial nerves and terminate in brain stem. 2 and 3 - part of CNS and are part of ascending sensory fibre tracts in spinal chord, relay info to cerebral cortex

Question 14

Pseudounipolar neuron

Answer 14

A neuron that has an axon that has split into two branches - one branch to the PNS and the other to the CNS. Most peripheral sensory afferent neurons are pseudounipolar

Question 15

Mechanoreceptors

Answer 15

pressure, sound eg hair cells in ear

Question 16

chemoreceptors

Answer 16

chemical substances, eg taste buds and olfactory cells in nose

Question 17

thermoreceptors

Answer 17

temperature, egnerve edings in skin and hypothalamus in brain

Question 18

photoreceptors

Answer 18

light, eg rods and cones in retina of eyes

Question 19

nociceptors

Answer 19

invloved in perception of pain

Question 20

What is receptor potential caused by

Answer 20

inreasced membrane ion flux (usually na or ca) due to change in gated ion channels that are responsive to the stimulus

Question 21

Receptive fields

Answer 21

the area within which a sensory receptor can respond to a stimulus. they may overlap, max sensitivity is the largest area of overlap

Question 22

Lateral inhibition

Answer 22

the most strongly activated neurons at the centre inhibit the less excited neurons in the surrounding areas (makes stimulus easier to percieve and localise

Question 23

sensory adaptation

Answer 23

when sensory receptors reduce their sensitivity to the stimulus

Question 24

Slowly adapting receptors (SA)

Answer 24

Tonic receptors - gradual adaptation to a constant stimulus

Question 25

Rapidly adapting receptors (RA)

Answer 25

Phasic receptors - adapt quickly

Question 26

Pacinian corpuscles

Answer 26

pressure receptors sensitive to vibration located in the dermal layer of the skin (more abundant on palms) large oval shaped, phasic receptors, large receptive fields on skin’s surface

Question 27

Mesissner’s corpuscle

Answer 27

found in upper dermis in hairless skin regions of fingertips and eyelids. respon to fine touch and pressure but also low frequency vibration or flutter. rapidly adapting, fluid filled encapsulated neurons with a small receptive field