Pineal gland interface between the photoperiodic environment and the endocrine system.

R J Reiter1

  • 1Department of Cellular and Structural Biology, The University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78284-7762, USA.

Summary

The pineal gland uses circadian melatonin rhythms to signal the body. This hormone influences seasonal reproduction, immune function, and other critical bodily processes.

Related Concept Videos

The Pineal Gland01:02

The Pineal Gland

The pineal gland, a diminutive endocrine structure named for its pinecone-shaped appearance, is situated atop the third ventricle within the diencephalon region of the forebrain. This gland, composed of secretory cells known as pinealocytes arranged in compact cords and clusters around dense particles of calcium salts, plays a pivotal role in hormonal regulation.
The primary secretion of the pineal gland is the hormone melatonin, derived from serotonin. The concentration of melatonin in the...
Structures of the Endocrine System00:59

Structures of the Endocrine System

The intricate framework of the endocrine system encompasses a diverse array of glands, with their target tissues and organs strategically distributed throughout the body. Central to this network are the endocrine glands, specialized structures that lack ducts and release hormones directly into the interstitial fluid. Notably, the hypothalamus, a vital neuroendocrine organ situated in the brain, governs neural functions and serves as a potent source of hormonal regulation. Near the hypothalamus...
The Pituitary Gland01:17

The Pituitary Gland

The pituitary is a small endocrine organ in the sphenoid bone under the hypothalamus. Primarily, the pituitary in adults has two distinct anatomical and functional regions— the anterior and posterior lobes. During human fetal development, a third pituitary gland region called the pars intermedia atrophies and disappears. However, some of its cells migrate and exist adjacent to the anterior pituitary in adults.
Biological Clocks and Seasonal Responses02:45

Biological Clocks and Seasonal Responses

The circadian—or biological—clock is an intrinsic, timekeeping, molecular mechanism that allows plants to coordinate physiological activities over 24-hour cycles called circadian rhythms. Photoperiodism is a collective term for the biological responses of plants to variations in the relative lengths of dark and light periods. The period of light-exposure is called the photoperiod.
Major Hormones and Their Functions01:27

Major Hormones and Their Functions

Hormones, the biochemical messengers produced by endocrine glands, are pivotal in regulating bodily functions and maintaining homeostasis. Each hormone's balance is crucial; imbalances can lead to significant physiological disruptions. Major hormones include oxytocin, cortisol, epinephrine, estrogen, testosterone, thyroxine, growth hormone, insulin, and glucagon.
Oxytocin, produced in the hypothalamus and released by the pituitary gland, plays a role in social bonding, childbirth, and lactation.
An Overview of the Endocrine System01:10

An Overview of the Endocrine System

The endocrine system, a complex network of glands, orchestrates physiological balance within the body through the production and secretion of hormones. These hormones are chemical messengers in intercellular communication, acting as conduits between the secretory cells and distant target sites. They traverse the circulatory system by being released into the extracellular fluid, and their impact is specific to cells possessing receptors for a particular hormone.
The endocrine system collaborates...