Rods and cones

[Boots]

I was doing the MC from psych notes and one of the answers said that rods and cones are at the back of the retina so are the last neurons reached my incoming light.

I thought they were the first, then bipolar then ganglion?

[yien_quek]

so what exactly was the question?? and what options do you get?

[Boots]

Which of the following statements are false:

A) Rods are monochromatic
B) Cones operate best in bright light
C) Rods are more plentiful than cones
D) Rods and cones are the first neurons reached by incoming light

[yien_quek]

okay, i admit, that was a tricky question, but if you give it some thought, rods and cones are NOT the first neurons reached by incoming light. they are the first to REACT with the light. if you take a look at the diagram of the back of the eye in the Grivas textbook, light has to go through a layer of ganglion cells, then bipolar cells, and then it finally reaches the rods and cones.

what you said is partially correct, in that rods and cones are the first to absorb the light, which then activates the bipolar cells, and then the ganglion cells.

if anyone has another answer, please do share, i am not 100% sure, but sure enough to choose D.

cheers!

[akira88]

Isn't the answer C?
There are about 120 million rods whereas there are only 6-7 million cones

[TrueLight]

The answer is D

The question says which one is false. C is correct but no rods at fovea.

[Slumdawg]

Which of the following statements are false:

A) Rods are monochromatic
B) Cones operate best in bright light
C) Rods are more plentiful than cones
D) Rods and cones are the first neurons reached by incoming light

Well option D is the correct answer since Ganglion cells are the first NEURONS reached by incoming light then bipolar cells. Rods and cones are at the VERY BACK of the retina. Hence the statement that they are the first neurons reached is incorrect and as it wants the incorrect statement it is the best option.

Ganglion cells and Bipolar Cells are both sensory neurons. So for future reference  the first neurons reached by light in the eye are ganglion cells followed by bipolar cells.

Choosing C would be something which is true. There are definitely more rods than cones, however the question asks for what is false so thats wrong. And the other two statements are true as well so they can be cancelled out as well.

Hope that helps. If you have any other questions just ask.

[akira88]

The answer is D

The question says which one is false. C is correct but no rods at fovea.

Oops I read the question wrong, lol bad mistake

[Boots]

okay, i admit, that was a tricky question, but if you give it some thought, rods and cones are NOT the first neurons reached by incoming light. they are the first to REACT with the light. if you take a look at the diagram of the back of the eye in the Grivas textbook, light has to go through a layer of ganglion cells, then bipolar cells, and then it finally reaches the rods and cones.

what you said is partially correct, in that rods and cones are the first to absorb the light, which then activates the bipolar cells, and then the ganglion cells.

if anyone has another answer, please do share, i am not 100% sure, but sure enough to choose D.

cheers!

great explanation