Human Anatomy, Part 1 - K. A. Dyubenko, A. K. Kolomiytsev, Yu. B. Chaykovsky 2002

Special Part
Endocrine glands (ductless glands), glandulae endocrinae (glandulae sine ductibus)
Central Regulatory Organs - Pineal Gland

The Pineal Gland, or epiphysis cerebri [corpus pineale], is an unpaired organ that resembles a slightly flattened, egg-shaped body. It is located above the superior colliculi of the Midbrain tectum and reaches up to 8 mm in length. Its posterior, pointed end is directed backward, while the thickened anterior end faces forward. The pineal gland has a reddish-gray color. The average weight of the gland in newborns is about 0.008 g, in men 0.125 g, and in women 0.11 g. The gland reaches its maximum development during childhood.

The outer surface of the gland is enclosed by a Connective Tissue capsule, which extends trabeculae into the parenchyma, dividing it into lobules. The parenchyma contains two MAIN TYPES OF Cells: pinealocytes (serotonin-producing cells) and supporting glial cells.

Functions of the pineal gland. The pineal gland inhibits The Development of the Reproductive System; therefore, experimental damage or removal of the pineal gland in animals leads to precocious Puberty.

Pinealocytes produce serotonin, which is converted into melatonin and distributed throughout the body, affecting Skin pigment cells. Pinealocytes also secrete a hormone, gonadotropin, which suppresses the action of luteinizing hormone produced by the anterior pituitary.

In addition, pinealocytes secrete a hormone that increases Blood potassium levels. The number of regulatory Peptides produced by the pineal gland approaches 40, the most important of which are Arginine vasotocin, thyrotropin-releasing hormone (TRH), luteinizing hormone-releasing hormone (LHRH), and thyrotropin.

The Blood supply to the pineal gland is provided by Branches of the posterior cerebral and superior cerebellar Arteries. Venous blood drains into the great cerebral vein or its tributaries.

Innervation of the pineal gland is supplied by sympathetic nerve fibers originating from the superior cervical sympathetic ganglia, which enhance The conversion of serotonin into melatonin.



Last update: 08/08/2026

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