rods and cones

Question 1

What are the stimulus in relation to these receptors?

Answer 1

= light

Question 2

Whwre do we find these light receptors?

Answer 2

= back in the eye, retina

Question 3

what are the 2 types of light receptirs?

Answer 3

= rod cells
= cones cells
= convert light energy into an electrical impulse- treansucers

Question 4

What happens to nerve ikmpulses from the retina where do they go?

Answer 4

= pass down optic nerve to the brain

Question 5

Hoq do rod cells work?

Answer 5

= several rod cells signal to one bipolar nueron by synpases
= retinal convergence
= each bipolar nueron signals to one sensory nueron to the brain
= rod cells have a light senseitive pigment called rhodopsin

Question 6

what happens when light hits the rod cells?

Answer 6

= rhodopsin molecules are broken down, rod cells cause bipolar nueron to depolroaise, if this reaches threhsol a generator potential is triggered and this triggers a nerve impulse to the bipolar nueron, down the sensoy nueron to the brain

Question 7

What are rod cells sensitive to?

Answer 7

= low light intensity
= rhodopsin does not ake a lot of energy to break down
= several rod cells are connected to same bipolar nueron, signals from rod cells add together- spatial summation increases chancde of threshold and geneatir potential, as there is enough neurotransmitters

Question 8

What is a problem with rod cells however ?

Answer 8

= brain cannot distinguish which indidual rod cell absorbed light
= low light intensity so low visual actucity, low resolution
= black ad white

Question 9

How do cone cells work?

Answer 9

= cone cells respond to high intensity light
= each cone cell connects to indivdual biopolar nueron, so each cone cell must trigger the genrator potential for its own nueron, sothere is no summation
= cone cells contain light sensitve pogment iodospin, contains high light intensity to break down,
=

Question 10

What 3 different types of cone cells are there?

Answer 10

= each type of cone cell contains a different form of iodopsin responding to a different wavelenfth og light
= impulses can be used to form coloured images in the brain
=

Question 11

What is thr asdvantage of cone cells?

Answer 11

= each cone cells connects to its own individual biopolar nueron, brain can determine which cone cell has absorbed light, high resolution, high visyal acutivyt

Question 12

where do we find the highest concentration of cone cells?

Answer 12

= fovea
= greatst light intensity recieved

Question 13

Where are rods found?

Answer 13

= egd eof retina, where light intensity is lower