cells

DEFINITION:

See definitions for "cell."

cells

DEFINITION:

See definitions for "cell."

cellular

DEFINITION:

Pertaining to, or made up of, cells.

hypophysiotropic

DEFINITION:

Acting on the hypophysis (pituitary gland), as a hypothalamic hypophysiotropic hormone.

hormones

DEFINITION:

In the singular: A product of living cells that circulates in body fluids and produces a specific effect on the activity of cells remote from its point of origin; especially: one exerting a stimulatory effect on a cellular activity.

hypophysiotropic hormones - Hormones produced by the hypothalamus, usually releasing hormones (see below), which maintain the endocrine functions of cells of the adenohypophysis.

neurohormone - A hormone secreted by a specialized neuron into the bloodstream, the cerebrospinal fluid, or the intercellular spaces of the nervous system.

releasing hormones - Hormones elaborated in one structure that cause the release of hormones from another structure, such as those from the hypothalamus that act on the adenohypophysis. The term is applied to substances of established chemical identity, whereas substances of unknown chemical structure are called releasing factors .

hormones

DEFINITION:

In the singular: A product of living cells that circulates in body fluids and produces a specific effect on the activity of cells remote from its point of origin; especially: one exerting a stimulatory effect on a cellular activity.

hypophysiotropic hormones - Hormones produced by the hypothalamus, usually releasing hormones (see below), which maintain the endocrine functions of cells of the adenohypophysis.

neurohormone - A hormone secreted by a specialized neuron into the bloodstream, the cerebrospinal fluid, or the intercellular spaces of the nervous system.

releasing hormones - Hormones elaborated in one structure that cause the release of hormones from another structure, such as those from the hypothalamus that act on the adenohypophysis. The term is applied to substances of established chemical identity, whereas substances of unknown chemical structure are called releasing factors .

hypothalamus

DEFINITION:

The ventral part of the diencephalon that forms the floor and part of the lateral wall of the third ventricle. Anatomically, it includes the preoptic area, optic tract, optic chiasm, mamillary bodies, tuber cinereum, infundibulum, and neurohypophysis, but for physiological purposes the neurohypophysis is considered a distinct structure. The hypothalamus may be divided into four regions (anterior, dorsalis, intermedia, and posterior) or into three longitudinal zones (periventricular zone, medial zone, and lateral zone). The hypothalamic nuclei constitute that part of the corticodiencephalic mechanism that activates, controls and integrates the peripheral autonomic mechanisms, endocrine activity, and many somatic functions, e.g., a general regulation of water balance, body temperature, sleep, and food intake, and the development of secondary sex characteristics. The hypothalamus secretes vasopressin and oxytocin, which are stored in the pituitary, as well as many releasing factors (hypophysiotropic hormones), by means of which it exerts control over functions of the adenohypophysis portion of the pituitary gland.

releasing hormones

DEFINITION:

See under hormone.

endocrine

DEFINITION:

1. Secreting internally; applied to organs and structures that release their products into the blood or lymph, and to substances (hormones) that exert specific effects on other organs.

2. Pertaining to internal secretions; hormonal.

cells

DEFINITION:

See definitions for "cell."

adenohypophysis

DEFINITION:

The anterior lobe of the pituitary gland. It secretes growth hormone, fibroblast growth hormone, corticotropin, ß-endorphin, thyroid-stimulating hormone, follicle-stimulating hormone, luteinizing hormone, and prolactin; these are released or inhibited by the actions of the pituitary of hypophysiotropic factors secreted by the hypothalamus, and they regulate the functioning of the thyroid, gonads, adrenal cortex, and other endocrine organs. As a consequence, the hypothalamo-pituitary unit is of vital importance to the growth, maturation, and reproduction of the individual. The adenohypophysis comprises the pars tuberalis and the pars distalis (the main body of the adenohypophysis); the pars intermedia contains cells that secrete ß-endorphin, melanotropins, and other regulators but is sometimes considered to be part of the neurohypophysis. The adenohypophysis has its origin in the buccal epithelium of the embryo. Called also anterior pituitary.

secreted

DEFINITION:

Having seperated or elaborated cell products.

neuron

DEFINITION:

Any of the conducting cells of the nervous system. A typical neuron consists of a cell body, containing the nucleus and the surrounding cytoplasm (perikaryon); several short radiating processes (dendrites); and one long process (the axon), which terminates in twiglike branches (telodendrons) and may have branches (collaterals) projecting along its course. The axon together with its covering or sheath forms the nerve fiber. Called also nerve cell.

bloodstream

DEFINITION:

The blood flowing through the circulatory system in the living body.

intercellular

DEFINITION:

Situated between the cells of any structure.

nervous system

DEFINITION:

The bodily system that is made up of the brain and spinal cord, nerves, ganglia, and parts of the receptor organs and that receives and interprets stimuli and transmits impulses to the effector organs.

releasing hormones

DEFINITION:

See under hormone.

hormones

DEFINITION:

In the singular: A product of living cells that circulates in body fluids and produces a specific effect on the activity of cells remote from its point of origin; especially: one exerting a stimulatory effect on a cellular activity.

hypophysiotropic hormones - Hormones produced by the hypothalamus, usually releasing hormones (see below), which maintain the endocrine functions of cells of the adenohypophysis.

neurohormone - A hormone secreted by a specialized neuron into the bloodstream, the cerebrospinal fluid, or the intercellular spaces of the nervous system.

releasing hormones - Hormones elaborated in one structure that cause the release of hormones from another structure, such as those from the hypothalamus that act on the adenohypophysis. The term is applied to substances of established chemical identity, whereas substances of unknown chemical structure are called releasing factors .

elaborated

DEFINITION:

1. Having produced complex substances out of simpler materials.

2. Worked out in detail; develop fully.

3. Planned or carried out with great care.

4. Being complex and usually ornate.

hormones

DEFINITION:

In the singular: A product of living cells that circulates in body fluids and produces a specific effect on the activity of cells remote from its point of origin; especially: one exerting a stimulatory effect on a cellular activity.

hypophysiotropic hormones - Hormones produced by the hypothalamus, usually releasing hormones (see below), which maintain the endocrine functions of cells of the adenohypophysis.

neurohormone - A hormone secreted by a specialized neuron into the bloodstream, the cerebrospinal fluid, or the intercellular spaces of the nervous system.

releasing hormones - Hormones elaborated in one structure that cause the release of hormones from another structure, such as those from the hypothalamus that act on the adenohypophysis. The term is applied to substances of established chemical identity, whereas substances of unknown chemical structure are called releasing factors .

hypothalamus

DEFINITION:

The ventral part of the diencephalon that forms the floor and part of the lateral wall of the third ventricle. Anatomically, it includes the preoptic area, optic tract, optic chiasm, mamillary bodies, tuber cinereum, infundibulum, and neurohypophysis, but for physiological purposes the neurohypophysis is considered a distinct structure. The hypothalamus may be divided into four regions (anterior, dorsalis, intermedia, and posterior) or into three longitudinal zones (periventricular zone, medial zone, and lateral zone). The hypothalamic nuclei constitute that part of the corticodiencephalic mechanism that activates, controls and integrates the peripheral autonomic mechanisms, endocrine activity, and many somatic functions, e.g., a general regulation of water balance, body temperature, sleep, and food intake, and the development of secondary sex characteristics. The hypothalamus secretes vasopressin and oxytocin, which are stored in the pituitary, as well as many releasing factors (hypophysiotropic hormones), by means of which it exerts control over functions of the adenohypophysis portion of the pituitary gland.

adenohypophysis

DEFINITION:

The anterior lobe of the pituitary gland. It secretes growth hormone, fibroblast growth hormone, corticotropin, ß-endorphin, thyroid-stimulating hormone, follicle-stimulating hormone, luteinizing hormone, and prolactin; these are released or inhibited by the actions of the pituitary of hypophysiotropic factors secreted by the hypothalamus, and they regulate the functioning of the thyroid, gonads, adrenal cortex, and other endocrine organs. As a consequence, the hypothalamo-pituitary unit is of vital importance to the growth, maturation, and reproduction of the individual. The adenohypophysis comprises the pars tuberalis and the pars distalis (the main body of the adenohypophysis); the pars intermedia contains cells that secrete ß-endorphin, melanotropins, and other regulators but is sometimes considered to be part of the neurohypophysis. The adenohypophysis has its origin in the buccal epithelium of the embryo. Called also anterior pituitary.

chemical

DEFINITION:

1. Of, or pertaining to, chemistry.

2. A substance composed of chemical elements, or obtained by chemical processes.

chemical

DEFINITION:

1. Of, or pertaining to, chemistry.

2. A substance composed of chemical elements, or obtained by chemical processes.

releasing factors

DEFINITION:

1. Factors elaborated in one structure (such as the hypothalamus) that effect the release of hormones from another structure (such as anterior pituitary gland). The term is applied to substances of unknown chemical structure, while substances of established chemical identity are called releasing hormones .

2. Two soluble proteins (RF-1 and RF-2) involved in the release of the completed polypeptide chain from the ribosome when a chain-termination codon is encountered during protein synthesis. RF-1 recognizes the termination codon UAA or UAG and RF-2 recognizes UAA or UGA.