24.2 role of receptors

Question 1

sensory reception vs sensory perception

Answer 1

• reception; function of sensory cells and organs

- perception; involves making sense of the information from the receptors

Question 2

features of the Pacinian corpuscle

Answer 2

• it is a receptor
• it is specific to a single type of stimulus
• produces a generator potential by acting as a transducer

Question 3

what stimulus does Pacinian corpuscle respond to

Answer 3

• changes in mechanical pressure

Question 4

role of a transducer

Answer 4

• converts energy from one form to another
• in this case; converts mechanical energy from stimulus to another type of energy that can be processed by nerve impulses

Question 5

generator impulse

Answer 5

• the nervous impulse to which all receptors convert the energy of a stimulus into

Question 6

where does the Pacinian corpuscle occur

Answer 6

• deep in the skin, most abundant in fingers
• soles of the feet
• external genitalia
• joints
• ligaments
• tendons

Question 7

structure of Panician corpuscle

Answer 7

• has a single sensory neurone in the center of layers of tissue
• the sensory neurone ending at the center has a type of sodium channels in its plasma memberane called the stretch-mediated sodium ion channel
• layers of connective tissue with viscous gel in between
  (this gives it the appearance of an onion when cut vertically)

Question 8

how does the stretch-mediated sodium ion channel work

Answer 8

• their pearmeability to sodium ions changes when they change shape - by stretching

Question 9

function of Pacinian corpuscle - 1) resting state

Answer 9

• the stretch-mediated sodium channels of the memberane around the sensory neurones are too narrow to allow sodium ions to pass along them
• in this state, the neurone is at resting potential

Question 10

function of Pacinian corpuscle - 2) pressure applied

Answer 10

• Pacinian corpuscle changes shape and membrane around the sensory neurone becomes stretched
• this stretching widens the SMSC in the membrane
• sodium ions diffuse into the neurons

Question 11

function of Pacinian corpuscle - 3) influx of sodium ions

Answer 11

• influx of sodium ions changes the potential of the memberane
• it becomes depolarised
• therefore, generator potential produced

Question 12

function of Pacinian corpuscle - 4) generator potential

Answer 12

• generator potential in turn creates an action potential (nerve impulse) that passes along the neurons
• then via other neurones and to the CNS