PATHOLOGY

Detailed explanation-1: -Melatonin is a hormone secreted by the enigmatic pineal gland in response to darkness, hence the name hormone of darkness.

Detailed explanation-2: -The pineal gland or epiphysis synthesizes and secretes melatonin, a structurally simple hormone that communicates information about environmental lighting to various parts of the body. Ultimately, melatonin has the ability to entrain biological rhythms and has important effects on reproductive function of many animals.

Detailed explanation-3: -It is a pinecone-shaped small gland located in the middle of the human brain in between the two hemispheres in an area called epithalamus. It was once known as “the third eye”. It is the major site for melatonin secretion, which regulates the body’s internal clock (Circadian rhythm).