When light enters the retina of the eyes, this signal is sent through the optic nerve to a region of the hypothalamus called the suprachiasmatic nucleus. This pathway is called the retinohypothalamic tract. From the suprachiasmatic nucleus, nerve impulses via the sympathetic nervous system travel to the pineal gland and inhibit the production of melatonin. At night, these impulses stop (because no light stimulates the hypothalamus) and melatonin production ensues and is released into the body.

what kind of nervous are in the upward tract?

what kind of nervous are in the upward tract?

what kind of nervous are in the upward tract?

what kind of nervous are in the upward tract?

what kind of nervous are in the upward tract?

what kind of nervous are in the upward tract?

what kind of nervous are in the upward tract?

what kind of nervous are in the upward tract?

what kind of nervous are in the upward tract?

what kind of nervous are in the upward tract?

what kind of nervous are in the upward tract?

what kind of nervous are in the upward tract?

what kind of nervous are in the upward tract?

what kind of nervous are in the upward tract?

what kind of nervous are in the upward tract?

what kind of nervous are in the upward tract?

what kind of nervous are in the upward tract?

what kind of nervous are in the upward tract?

what kind of nervous are in the upward tract?

what kind of nervous are in the upward tract?

GI tract, GIT, digestive tract, digestion tract, alimentary canal

tract

Urinary tract.