The body uses Choose...twothreefivenine active forms of vitamin A, known collectively as the Choose...fibroidsretinolsretinoidsnone of the above. While all three forms have essential functions, Choose...retinolretinalrhodopsinretinoic acid is the key player in the vitamin A family. In well-nourished people, the Choose...muscle tissueliverspleenblood cells stores more than (90%) of the body’s vitamin A. The remainder is stored in adipose tissue, lungs, and kidneys. Vitamin A is important to vision. In the eye, retinal combines with opsin to form a pigment called Choose...rhodopsinretinyliodopsinreto-opsin which makes it possible to see in dim light. Vitamin A is also involved in color vision as part of the pigment in Choose...stem cellscone cellsgoblet cellsrod cells. A lack of vitamin A effects rod cells first so as a vitamin A deficiency worsens Choose...night blindnessdark adaptationcolor blindnessteratogens emerges before Choose...night blindnessdark adaptationcolor blindnessteratogens. A large proportion of the body’s vitamin A is in the form of retinoic acid. It is involved in cell differentiation, the process when Choose...cone cellsgoblet cellsstem cellsrod cells develop into specific types of cells with unique functions.

The best sources of provitamin A carotenoids are dark green and Choose...yellow-orangered-orangedeep purpleorange vegetables. Vitamin A deficiency is the leading cause of Choose...ricketskwashiorkorinfant mortalitychildhood blindness in the world.