hypothalamus

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hy·po·thal·a·mus

(hī'pō-thal'ă-mŭs), [TA]
The ventral and medial regions of the diencephalon forming the walls of approximately the ventral half of the third ventricle; it is delineated from the thalamus by the hypothalamic sulcus, lying medial to the internal capsule and subthalamus, continuous with the precommissural septum anteriorly and with the mesencephalic tegmentum and central gray substance posteriorly. Its ventral surface is marked by (from rostral to caudal) the optic chiasma, the unpaired infundibulum that extends by way of the infundibular stalk into the posterior lobe of the hypophysis, and the paired mammillary bodies. The hypothalamus consists of the anterior hypothalamic area [TA], dorsal hypothalamic area [TA], intermediate hypothalamic area [TA], lateral hypothalamic area [TA], and posterior hypothalamic area [TA], each of these containing specific nuclei. It has afferent fiber connections with the mesencephalon, limbic system, cerebellum, and efferent fiber connections with the same structures and with the posterior lobe of the hypophysis; its functional connection with the anterior lobe of the hypophysis is established by the hypothalamohypophysial portal system. The hypothalamus is prominently involved in the functions of the autonomic (visceral motor) nervous system and, through its vascular link with the anterior lobe of the hypophysis, in endocrine mechanisms; it also appears to play a role in neural mechanisms underlying moods and motivational states.
See also: pituitary gland.
[hypo- + thalamus]

hypothalamus

/hy·po·thal·a·mus/ (-thal´ah-mus) the part of the diencephalon forming the floor and part of the lateral wall of the third ventricle, including the optic chiasm, mammillary bodies, tuber cinereum, and infundibulum; the pituitary gland is also in this region but is physiologically distinct. Hypothalamic nuclei help activate, control, and integrate peripheral autonomic mechanisms, endocrine activities, and many somatic functions.hypothalam´ic

hypothalamus

(hī′pō-thăl′ə-məs)
n.
The part of the brain that lies below the thalamus, forming the major portion of the ventral region of the diencephalon and functioning to regulate bodily temperature, certain metabolic processes, and other autonomic activities.

hy′po·tha·lam′ic (-thə-lăm′ĭk) adj.

hypothalamus

[hī′pōthal′əməs]
Etymology: Gk, hypo + thalamos, chamber
a portion of the diencephalon of the brain, forming the floor and part of the lateral wall of the third ventricle. It activates, controls, and integrates the peripheral autonomic nervous system, endocrine processes, and many somatic functions, such as body temperature, sleep, and appetite. Compare epithalamus, metathalamus, subthalamus, thalamus. hypothalamic, adj.

hy·po·thal·a·mus

(hī'pō-thal'ă-mŭs) [TA]
The ventral and medial region of the diencephalon forming the walls of the ventral half of the third ventricle; delineated from the thalamus by the hypothalamic sulcus, lying medial to the internal capsule and subthalamus, continuous with the precommissural septum anteriorly and with the mesencephalic tegmentum and central gray substance posteriorly. Its ventral surface is marked by, from before backward, the optic chiasma, the unpaired infundibulum, which extends by way of the infundibular stalk into the posterior lobe of the hypophysis, and the paired mammillary bodies. The nerve cells of the hypothalamus are grouped into the supraoptic paraventricular, lateral preoptic, lateral hypothalamic, tuberal, anterior hypothalamic, ventromedial, dorsomedial, arcuate, posterior hypothalamic, and premammillary nuclei and into the mammillary body. It has afferent fiber connections with the mesencephalon, limbic system, cerebellum, and efferent fiber connections with the same structures and with the posterior lobe of the hypophysis; its functional connection with the anterior lobe of the hypophysis is established by the hypothalamohypophysial portal system. The hypothalamus is prominently involved in the functions of the autonomic nervous system and, through its vascular link with the anterior lobe of the hypophysis, in endocrine mechanisms; it also appears to play a role in neural mechanisms underlying moods and motivational states.
See also: hypophysis

hypothalamus

The region of the under-surface of the brain immediately above the pituitary gland. The hypothalamus is the area in which the nervous and hormonal systems of the body interact. It receives information relating to hormone levels, physical and mental stress, the emotions and the need for physical activity, and responds by prompting the pituitary appropriately. Nuclei in the lower region of the hypothalamus contain neurons that secrete growth hormone releasing hormone, gonadotropin releasing hormone, somatostatin and other regulating substances.

hypothalamus

the part of the sides and floor of the brain derived from the forebrain. Associated with the control of body temperature, it also partially controls the PITUITARY GLAND and contains centres controlling sleep and wakefulness, feeding, drinking, speech and osmoregulation, the last by secretion of ADH from neurosecretory cells. It is also associated with aspects of reproductive behaviour.

Hypothalamus

A structure within the brain responsible for a large number of normal functions throughout the body, including regulating sleep, temperature, eating, and sexual development. The hypothalamus also regulates the functions of the pituitary gland by directing the pituitary to stop or start production of its hormones.

hypothalamus

region of the brain which links cerebral function to the endocrine system, initiates physio logical responses to emotions and regulates eating and drinking behaviour, body temperature and circadian rhythms. Many of these actions are mediated via the autonomic nervous system. Secretes specific 'releasing' and 'inhibitory' hormones into local blood vessels that reach the anterior pituitary and influence the secretion of its hormones; also the neurohormones oxytocin and antidiuretic hormone (vasopressin) are formed here in nerve cell bodies and travel down axons in the hypothalamo-hypophyseal tract to be stored in, until released from, their terminals in the posterior pituitary. See also appetite, body temperature, hormones, thirst.

hypothalamus

ventral and medial regions of diencephalon, governing many autonomic functions, including body rhythms; secretes releasing factors (that act on anterior pituitary via hypothalamic vascular portal system) to govern secretion of many hormones; also influences neurological mechanisms that underlie mood and motivational states

hypothalamus

A group of nuclei at the base of the brain located in the floor of the third ventricle. It consists of the optic chiasma, the paired mammillary bodies, the tuber cinereum, the infundibulum and the pars posterior of the pituitary gland.

hy·po·thal·a·mus

(hī'pō-thal'ă-mŭs) [TA]
Ventral and medial regions of diencephalon forming walls of approximately the ventral half of third ventricle; delineated from the thalamus by the hypothalamic sulcus, lying medial to the internal capsule and subthalamus, continuous with the precommissural septum anteriorly and with the mesencephalic tegmentum and central gray substance posteriorly.
[hypo- + thalamus]

hypothalamus (hī´pōthal´əmus),

n a small extension of the brain that lies in the sella turcica in the cranium. It lies just at the superior level of the body of the sphenoid bone. It is intimately related structurally and functionally with the pituitary gland and is important in the central regulation of the endocrine glands, including the thyroid gland, pancreas, adrenal glands, and gonads. The most important visceral functions are under control of the hypothalamus because it functions in such close coordination with the endocrine glands. The control is mediated through its structural communication with the pituitary gland.

hypothalamus

the portion of the diencephalon lying beneath the thalamus at the base of the cerebrum, and forming the floor and part of the lateral wall of the third ventricle. It includes the optic chiasm, mammillary bodies, tuber cinereum, infundibulum and hypophysis (pituitary gland), but for physiological purposes, the hypophysis is considered a distinct structure.
The hypothalamic nuclei activate, control and integrate many of the involuntary functions necessary for living. The various hypothalamic centers influence peripheral autonomic mechanisms, endocrine activity and many somatic functions, e.g. a general regulation of water balance, body temperature, sleep, thirst and hunger, and the development of secondary sex characteristics.
Because of its influence on the release and inhibition of pituitary hormones, the hypothalamus indirectly plays an important role in the regulation of protein, fat and carbohydrate metabolism, body fluid volume and electrolyte content, and internal secretion of endocrine hormones. The hormones synthesized and secreted by the special neurons of the hypothalamus are called hypothalamic releasing and inhibiting hormones or factors. They act directly on the tissues of the pituitary gland. Some of the major hypothalamic factors are: thyroid-stimulating hormone releasing hormone (TRH), which activates the release of the thyroid-stimulating hormone (TSH) from the anterior lobe of the pituitary gland; corticotropin-releasing factor (CRF); growth hormone releasing factor (GHRF); gonadotropin releasing hormone (GnRH); and prolactin-inhibiting factor (PIF). In addition, there are other stimulating and inhibiting factors that influence the release and retention of other anterior pituitary hormones.
The hypothalamic hormones or factors are secreted directly into the veins in the lower part of the hypothalamus and are transported directly to the tissues of the pituitary gland. This transportation network is called the hypothalamic-hypophyseal portal system. The secretion of the hypothalamic hormones is a part of a regulatory negative feedback system that continuously operates to maintain homeostasis.
References in periodicals archive ?
1 SKIN: Heat receptors in the skin send message to the heat loss centre in the hypothalmus.