Question

A small region on the retina of the eye which contains only cones is called as
A. Area centralis
B. Fovea centralis
C. Blind spot
D. Ora serrata

Answer 1

Hint:- The cone cells present in our eyes operate only in bright light, furthermore, they enable us to see colors. Hence the daylight (photopic) vision and color vision are the functions of cones.

Complete step-by-step solution:- An adult human eye consists of three layers, the outermost is the sclera, the middle one is the choroid and the innermost is the retina.
The inner coat of the eyeball is the retina, it contains the actual light receptors, the rods, and cones, and thus retina functions in the same way that of a film in the camera does. Theretina consists of three layers of cells from inside to outside: ganglion cells, bipolar cells, and the photoreceptor cells.
There are two types of photoreceptor cells, namely rods and cones which contain the light-sensitive proteins photo-pigments.Inner to the bipolar cells there is the layer of retinal ganglion cells. Bipolar cell synapse with the retinal ganglion cells. The axons of the retinal ganglion cells bundle together as the optic nerve.
The point on the retina where the optic nerve leaves the eyeball is called a blind spot,where photoreceptor cells are not present which means there are no rods or cone cells present in that spot. Therefore no image is formed in that spot which is why it is known as a blind spot.
At the posterior pole of the eye lateral to the blind spot, there is a yellowish pigment spot called the macula, it is also called the yellow spot. There is a central pit present in the macula lutea which is called the Fovea centralis.
The Fovea centralis is a thinned-out portion of the retina where only the cones are densely packed as a result fovea centralis is a point where the visual resolution is the greatest and the vision is the sharpest.
Thus the correct answer is Fovea centralis, option (B)

Note:-
-Yellow spot, blind spot as well as the fovea centralis all are present on the retina. The ora
serrata is a bridge that is located between the ciliary body and the retina of the eye.
-Area centralis is also known as macula lutea.