Question

In human eye, the blind spot contains
A. Rods
B. Cones
C. Both rods and cones
D. Neither rods nor cones

Answer 1

Hint: Photoreceptor is the specialized type of neuroepithelial cells found in the retina, and they have a special function called visual phototransduction, they have the capability to convert the photo signals to stimulus and to do the biological process.

Complete answer:
There are currently three types of photoreceptor cells in the mammals.
They are Rod cells, cone cells, and intrinsic photosensitive retinal ganglion cells.
When it comes to Rods and cones both are helpful for visual processes or site.
Rods are narrower in structure, and cones are distributed differently across the retina, even though both are differently arranged but the chemical reaction called phototransduction is the same in both.
Whereas in the 1990s another photosensitive retinal cell called ganglionic cells was discovered, these cells do not have any direct function in the site, but they are indirectly helpful for circadian rhythms and pupillary reflex.
When coming to the functional difference between the rods and cones, Rods are hypersensitive and can easily trigger by even a single photon, and cones require some large number of photons and to trigger the stimulus. So rods are the cells that help us to visualize during the dark nights.
Each retina contains 120 million rod cells and 60 million cones.
In mammals, the point of exit of the optic nerve results in a blind spot and it does not contain any rods and cones.

So the correct option is D.

Note:
Rods contain the pigment called rhodopsin which is useful for vision in the low light and cones contain the pigment called iodopsin, porphyropsin, and cyanopsin and these are helpful for daylight vision and color vision.