Anatomy and Physiology II Practice Test

Which vitamin is involved in vision and may lead to night blindness if deficient?

1. Vitamin D

2. Vitamin E

3. Vitamin A

4. Vitamin K

The correct answer is: Vitamin A

Vitamin A plays a crucial role in vision, particularly in the functioning of the retina. It is a key component of rhodopsin, a protein in the eyes that is essential for vision in low-light conditions. When light hits the retina, rhodopsin undergoes a chemical change that initiates the transmission of visual signals to the brain. If there is a deficiency of Vitamin A, the production of rhodopsin is impaired, leading to difficulties in adjusting to low light and potentially resulting in night blindness. In contrast, the other vitamins listed have different primary functions in the body. Vitamin D is mainly involved in calcium absorption and bone health, Vitamin E serves as an antioxidant protecting cell membranes, and Vitamin K is essential for blood clotting processes. None of these vitamins have a direct role in vision like Vitamin A does. This distinct function of Vitamin A in maintaining healthy eyesight underscores its importance and the repercussions of its deficiency.