14.4 receptors

Question 1

2 features of a receptor cell

Answer 1

1. is specific to a single type of stimulus
2. produces a greater potential by acting as a transducer

Question 2

transducer

Answer 2

converts the change in form of energy by stimulus into a form that the body can understand

i.e. nervous impulse- generator potential

Question 3

Pacinian corpuscle function

Answer 3

respond to mechanical stimuli
i.e. pressure

Question 4

location of pacinian corpuscle

Answer 4

deep in the skin

mostly in fingers, sole of feet and external genetilia

occur in joints, ligaments and tendons

Question 5

structure of pacinian corpuscle

Answer 5

layers of connective tissue with viscous gel between

neurone in the middle

attached to blood capillary

Question 6

stretch mediated sodium channel

Answer 6

sodium channel in plasma membrane of sensory neurone ending

permeability to sodium changes when deformed

Question 7

Pacinian corpuscle process

Answer 7

1. in normal state the SMSC are too narrow to allow Na+ ions to padd along them. It has a resting potential
2. When pressure is applied, it is deformed and the membrane around neurone is stretched
3. stretching widens the SMSC and Na+ ions diffuse into the neurone
4. influx of Na+ ions changes the potential of the membrane(becomes depolarised) creating a generator potential
5. generator potential creates an action potential(nerve impulse) that passes along the neurones to CNS

Question 8

receptor in the eye

Answer 8

light receptor- cone or rod
found on retina

Question 9

rod cells

Answer 9

cannot distinguish between different wavelengths of light

images only seen in black and white

lots more than cone

Question 10

rod cell generator potential

Answer 10

pigment rhodopsin must be broken down

caused by energy from low light-intensity

a threshold value must be exceeded before gpt is formed in connected bipolar cell

Question 11

retinal convergence

Answer 11

multiple rod cells are connected to single bipolar cell

light recieved only generates single impulse regardless of how many neurones are stimulated
-brain can’t distinguish between separate sources of light that stimulated them(low visual acuity)