Preoptic area
Encyclopedia
The preoptic area is a region of the hypothalamus
. According to the MeSH
classification, it is considered part of the anterior hypothalamus. There are four nuclei
in this region, according to Terminologia Anatomica
(Medial, Median, Lateral, and Paraventricular).
and receives nervous stimulation from thermoreceptors in the skin, mucous membrane
s, and hypothalamus itself.
This area propagates stimuli to either the heat-losing or the heat-promoting centers of the hypothalamus.
.
The median preoptic nucleus generates thirst
. Drinking decreases noradrenaline release in the median preoptic nucleus.
The medial preoptic nucleus is bounded laterally by the lateral preoptic nucleus, and medially by the preoptic periventricular nucleus. It releases gonadotropin-releasing hormone
, controls copulation in males, and is larger in males than in females.
as they grow old. The female mice that were given a calorie-restricted
diet during the majority of their lives, maintained higher levels of ERα in the pre-optic hypothalamus than their non-calorie-restricted counterparts.
Hypothalamus
The Hypothalamus is a portion of the brain that contains a number of small nuclei with a variety of functions...
. According to the MeSH
Medical Subject Headings
Medical Subject Headings is a comprehensive controlled vocabulary for the purpose of indexing journal articles and books in the life sciences; it can also serve as a thesaurus that facilitates searching...
classification, it is considered part of the anterior hypothalamus. There are four nuclei
Nucleus (neuroanatomy)
In neuroanatomy, a nucleus is a brain structure consisting of a relatively compact cluster of neurons. It is one of the two most common forms of nerve cell organization, the other being layered structures such as the cerebral cortex or cerebellar cortex. In anatomical sections, a nucleus shows up...
in this region, according to Terminologia Anatomica
Terminologia Anatomica
Terminologia Anatomica is the international standard on human anatomic terminology. It was developed by the Federative Committee on Anatomical Terminology and the International Federation of Associations of Anatomists and was released in 1998. It supersedes the previous standard, Nomina...
(Medial, Median, Lateral, and Paraventricular).
Functions
The preoptic area is responsible for thermoregulationThermoregulation
Thermoregulation is the ability of an organism to keep its body temperature within certain boundaries, even when the surrounding temperature is very different...
and receives nervous stimulation from thermoreceptors in the skin, mucous membrane
Mucous membrane
The mucous membranes are linings of mostly endodermal origin, covered in epithelium, which are involved in absorption and secretion. They line cavities that are exposed to the external environment and internal organs...
s, and hypothalamus itself.
This area propagates stimuli to either the heat-losing or the heat-promoting centers of the hypothalamus.
Median preoptic nucleus
The median preoptic nucleus is located along the midline in a position significantly dorsal to the other 3 preoptic nuclei, at least in the macaca fascicularis brain. It wraps around the top (dorsal), front, and bottom (ventral) surfaces of the anterior commissureAnterior commissure
The anterior commissure is a bundle of nerve fibers , connecting the two cerebral hemispheres across the midline, and placed in front of the columns of the fornix...
.
The median preoptic nucleus generates thirst
Thirst
Thirst is the craving for fluids, resulting in the basic instinct of animals to drink. It is an essential mechanism involved in fluid balance. It arises from a lack of fluids and/or an increase in the concentration of certain osmolites, such as salt...
. Drinking decreases noradrenaline release in the median preoptic nucleus.
Medial preoptic nucleus
The medial preoptic nucleus is bounded laterally by the lateral preoptic nucleus, and medially by the preoptic periventricular nucleus. It releases gonadotropin-releasing hormone
Gonadotropin-releasing hormone
Gonadotropin-releasing hormone , also known as Luteinizing-hormone-releasing hormone and luliberin, is a tropic peptide hormone responsible for the release of follicle-stimulating hormone and luteinizing hormone from the anterior pituitary. GnRH is synthesized and released from neurons within...
, controls copulation in males, and is larger in males than in females.
Lateral preoptic nucleus
The lateral preoptic nucleus is lateral to the medial preoptic nucleus. It also mediates non-REM sleep onset.Preoptic periventricular nucleus
The preoptic periventricular nucleus is located along the midline and is medial to the medial preoptic nucleus.Aging
Studies in female mice have shown that estrogen receptor-alpha declines in the pre-optic hypothalamusHypothalamus
The Hypothalamus is a portion of the brain that contains a number of small nuclei with a variety of functions...
as they grow old. The female mice that were given a calorie-restricted
Calorie restriction
Caloric restriction , or calorie restriction, is a dietary regimen that restricts calorie intake, where the baseline for the restriction varies, usually being the previous, unrestricted, intake of the subjects...
diet during the majority of their lives, maintained higher levels of ERα in the pre-optic hypothalamus than their non-calorie-restricted counterparts.