Question

What happens when a human comes in bright light?
A. Rhodopsin
B. Mydriasis
C. Miosis
D. None of the above

Answer 1

Rods and cones are specialised cells in vertebrates' eyes that aid in vision. Rod cells are positioned on the retina's outer margins, while cone cells are found near the retina's Centre. Rods are photosensitive cells with a high sensitivity to light. They are able to detect faint light. Cones are photosensitive cells with a low sensitivity to light. The retina has two types of photoreceptor cells: rods and cones, which react to intense light.

Complete answer:
Option A: Rhodopsin is a phototransduction-related light-sensitive receptor protein. Rhodopsin is a G-protein-coupled receptor and a biological pigment present in the rods of the retina.
Rhodopsin is a pigment-containing sensory protein that turns light into an electrical signal.
So, option A is not correct.
Option B: The dark rings in your eyes are called pupils. They collect light and direct it to the retina, where it is transformed into images. In most cases, the pupils dilate or widen in response to low light so that more light can be collected. Pupils can dilate for a variety of reasons unrelated to light levels in the environment. Even in bright surroundings, they may remain expanded. Mydriasis is the medical term for this illness.
So, option B is not correct
Option C: When the eye is exposed to strong light, light-sensitive cells in the retina, such as rod and cone photoreceptors, as well as melanopsin ganglion cells, transmit signals to the oculomotor nerve, specifically the parasympathetic part, which terminates on the circular iris sphincter muscle. When this muscle contracts, the pupil shrinks in size. The pupillary light reflex is a critical indicator of brainstem function. Miosis is a term for the narrowing of the pupil. Miotic substances are those that cause miosis.
So, option C is correct.
Option D: Light-sensitive cells in the retina transfer signals to the oculomotor nerve, which terminates on the circular iris sphincter muscle, when the eye is exposed to bright light. The pupil contracts when this muscle contracts. The term mitosis refers to the narrowing of the pupil.
So, option D is not correct.

So, option C is the correct answer.

Note:
Rods play a minor role in colour perception. Because the optic disc lacks cones, it is a blind zone. A human eye contains roughly six to seven million cones, the majority of which are located near the macula. They have a strong reaction to bright light. Cones are most important for colour vision during the day. In the retina, light is detected by rods and cones, and visual information is processed. The impulse is then delivered to the brain, where the image is viewed after it has entered the brain.