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-Where is melanocyte stimulating hormone produced ? adrenal gland, anterior pitu

ID: 3504426 • Letter: #

Question

-Where is melanocyte stimulating hormone produced ? adrenal gland, anterior pituitary gland, hypothalamus, or none of these

-What is the function of cGMP in the retina? locks cation channels open, locks voltage gated channels open, locks voltage gated channels closed, or none

-What is a major function of vitamin D3? increases intestinal production of secretion, decreases intestinal production of secretion, increases intestinal absorption of calcium and phospahate, or none

- The process by which, when in the dark, the eyes become more sensitive to light? transduction, sensitive adaptation, dark adaptation, or none

-Which compound is broken down by light in the photoreceptors? retinal, rhodopsin, cGMP, or none

-Which of the following causes an increase in the plasma levels of calcium? insulin, calcitonin, glucagon, parathyroid hormone

-Is rhodopsin produced in the light or in the dark? dark or none

-Which of the following has an stimulatory effect on mitosis??

Explanation / Answer

- melanocyte hormone is produced by pituitary gland. It can also produced by skin and responsible for production of dark pigment called melanin which is the reason for skin colour.

- cGMP in retina locks voltage gated channels open as cyclic nucleotides control permeation of ions and gating .

- Cholecalciferol or vitamin D3 is a fat soluble vitamin and increases intestinal absorption of calcium and phosphate which in turn helps in formation of strong bone.

- The process is called dark adaptation where photoreceptor photopigments recover under reduced illumination.

- when the light hits rhodopsin breaks down into retinal and opsin and then the cis form of retinal will change into trans form.

- Secretion of parathyroid hormone from parathyroid gland increases calcium level in blood plasma.

- When the light hits , photobleaching of rhodopsin occurs and rhodopsin regenerates in dark by dark adaptation.