Suprarenal glands Health Dictionary

Also known as suprarenal glands, these are two small triangular ENDOCRINE GLANDS situated one upon the upper end of each kidney. (See diagram of ABDOMEN.)

Structure Each suprarenal gland has an enveloping layer of ?brous tissue. Within this, the gland shows two distinct parts: an outer, ?rm, deep-yellow cortical (see CORTEX) layer, and a central, soft, dark-brown medullary (see MEDULLA) portion. The cortical part consists of columns of cells running from the surface inwards, whilst in the medullary portion the cells are arranged irregularly and separated from one another by large capillary blood vessels.

Functions Removal of the suprarenal glands in animals is speedily followed by great muscular prostration and death within a few days. In human beings, disease of the suprarenal glands usually causes ADDISON’S DISEASE, in which the chief symptoms are increasing weakness and bronzing of the skin. The medulla of the glands produces a substance – ADRENALINE – the effects of which closely resemble those brought about by activity of the SYMPATHETIC NERVOUS SYSTEM: dilated pupils, hair standing on end, quickening and strengthening of the heartbeat, immobilisation of the gut, increased output of sugar from the liver into the bloodstream. Several hormones (called CORTICOSTEROIDS) are produced in the cortex of the gland and play a vital role in the metabolism of the body. Some (such as aldosterone) control the electrolyte balance of the body and help to maintain the blood pressure and blood volume. Others are concerned in carbohydrate metabolism, whilst others again are concerned with sex physiology. HYDROCORTISONE is the most important hormone of the adrenal cortex, controlling as it does the body’s use of carbohydrates, fats and proteins. It also helps to suppress in?ammatory reactions and has an in?uence on the immune system.... adrenal glands

The glands that produce the saliva injected when a mosquito or other ectoparasite bites, which prevent blood from clotting while the mosquito feeds.... salivary glands

Glands that control the level of calcium in the blood. The four glands appear, two on each side, implanted in the thyroid gland in the front of the neck.

Disorders are (1) hypoparathyroidism and (2) hyperparathyroidism. See entries. ... parathyroid glands

Organs whose function it is to secrete into the blood or lymph, substances known as HORMONES. These play an important part in general changes to or the activities of other organs at a distance. Various diseases arise as the result of defects or excess in the internal secretions of the di?erent glands. The chief endocrine glands are:

Adrenal glands These two glands, also known as suprarenal glands, lie immediately above the kidneys. The central or medullary portion of the glands forms the secretions known as ADRENALINE (or epinephrine) and NORADRENALINE. Adrenaline acts upon structures innervated by sympathetic nerves. Brie?y, the blood vessels of the skin and of the abdominal viscera (except the intestines) are constricted, and at the same time the arteries of the muscles and the coronary arteries are dilated; systolic blood pressure rises; blood sugar increases; the metabolic rate rises; muscle fatigue is diminished. The super?cial or cortical part of the glands produces steroid-based substances such as aldosterone, cortisone, hydrocortisone, and deoxycortone acetate, for the maintenance of life. It is the absence of these substances, due to atrophy or destruction of the suprarenal cortex, that is responsible for the condition known as ADDISON’S DISEASE. (See CORTICOSTEROIDS.)

Ovaries and testicles The ovary (see OVARIES) secretes at least two hormones – known, respectively, as oestradiol (follicular hormone) and progesterone (corpus luteum hormone). Oestradiol develops (under the stimulus of the anterior pituitary lobe – see PITUITARY GLAND below, and under separate entry) each time an ovum in the ovary becomes mature, and causes extensive proliferation of the ENDOMETRIUM lining the UTERUS, a stage ending with shedding of the ovum about 14 days before the onset of MENSTRUATION. The corpus luteum, which then forms, secretes both progesterone and oestradiol. Progesterone brings about great activity of the glands in the endometrium. The uterus is now ready to receive the ovum if it is fertilised. If fertilisation does not occur, the corpus luteum degenerates, the hormones cease acting, and menstruation takes place.

The hormone secreted by the testicles (see TESTICLE) is known as TESTOSTERONE. It is responsible for the growth of the male secondary sex characteristics.

Pancreas This gland is situated in the upper part of the abdomen and, in addition to the digestive enzymes, it produces INSULIN within specialised cells (islets of Langerhans). This controls carbohydrate metabolism; faulty or absent insulin production causes DIABETES MELLITUS.

Parathyroid glands These are four minute glands lying at the side of, or behind, the thyroid (see below). They have a certain e?ect in controlling the absorption of calcium salts by the bones and other tissues. When their secretion is defective, TETANY occurs.

Pituitary gland This gland is attached to the base of the brain and rests in a hollow on the base of the skull. It is the most important of all endocrine glands and consists of two embryologically and functionally distinct lobes.

The function of the anterior lobe depends on the secretion by the HYPOTHALAMUS of certain ‘neuro-hormones’ which control the secretion of the pituitary trophic hormones. The hypothalamic centres involved in the control of speci?c pituitary hormones appear to be anatomically separate. Through the pituitary trophic hormones the activity of the thyroid, adrenal cortex and the sex glands is controlled. The anterior pituitary and the target glands are linked through a feedback control cycle. The liberation of trophic hormones is inhibited by a rising concentration of the circulating hormone of the target gland, and stimulated by a fall in its concentration. Six trophic (polypeptide) hormones are formed by the anterior pituitary. Growth hormone (GH) and prolactin are simple proteins formed in the acidophil cells. Follicle-stimulating hormone (FSH), luteinising hormone (LH) and thyroid-stimulating hormone (TSH) are glycoproteins formed in the basophil cells. Adrenocorticotrophic hormone (ACTH), although a polypeptide, is derived from basophil cells.

The posterior pituitary lobe, or neurohypophysis, is closely connected with the hypothalamus by the hypothalamic-hypophyseal tracts. It is concerned with the production or storage of OXYTOCIN and vasopressin (the antidiuretic hormone).

PITUITARY HORMONES Growth hormone, gonadotrophic hormone, adrenocorticotrophic hormone and thyrotrophic hormones can be assayed in blood or urine by radio-immunoassay techniques. Growth hormone extracted from human pituitary glands obtained at autopsy was available for clinical use until 1985, when it was withdrawn as it is believed to carry the virus responsible for CREUTZFELDT-JAKOB DISEASE (COD). However, growth hormone produced by DNA recombinant techniques is now available as somatropin. Synthetic growth hormone is used to treat de?ciency of the natural hormone in children and adults, TURNER’S SYNDROME and chronic renal insu?ciency in children.

Human pituitary gonadotrophins are readily obtained from post-menopausal urine. Commercial extracts from this source are available and are e?ective for treatment of infertility due to gonadotrophin insu?ciency.

The adrenocorticotrophic hormone is extracted from animal pituitary glands and has been available therapeutically for many years. It is used as a test of adrenal function, and, under certain circumstances, in conditions for which corticosteroid therapy is indicated (see CORTICOSTEROIDS). The pharmacologically active polypeptide of ACTH has been synthesised and is called tetracosactrin. Thyrotrophic hormone is also available but it has no therapeutic application.

HYPOTHALAMIC RELEASING HORMONES which affect the release of each of the six anterior pituitary hormones have been identi?ed. Their blood levels are only one-thousandth of those of the pituitary trophic hormones. The release of thyrotrophin, adrenocorticotrophin, growth hormone, follicle-stimulating hormone and luteinising hormone is stimulated, while release of prolactin is inhibited. The structure of the releasing hormones for TSH, FSH-LH, GH and, most recently, ACTH is known and they have all been synthesised. Thyrotrophin-releasing hormone (TRH) is used as a diagnostic test of thyroid function but it has no therapeutic application. FSH-LH-releasing hormone provides a useful diagnostic test of gonadotrophin reserve in patients with pituitary disease, and is now used in the treatment of infertility and AMENORRHOEA in patients with functional hypothalamic disturbance. As this is the most common variety of secondary amenorrhoea, the potential use is great. Most cases of congenital de?ciency of GH, FSH, LH and ACTH are due to defects in the hypothalamic production of releasing hormone and are not a primary pituitary defect, so that the therapeutic implication of this synthesised group of releasing hormones is considerable.

GALACTORRHOEA is frequently due to a microadenoma (see ADENOMA) of the pituitary. DOPAMINE is the prolactin-release inhibiting hormone. Its duration of action is short so its therapeutic value is limited. However, BROMOCRIPTINE is a dopamine agonist with a more prolonged action and is e?ective treatment for galactorrhoea.

Thyroid gland The functions of the thyroid gland are controlled by the pituitary gland (see above) and the hypothalamus, situated in the brain. The thyroid, situated in the front of the neck below the LARYNX, helps to regulate the body’s METABOLISM. It comprises two lobes each side of the TRACHEA joined by an isthmus. Two types of secretory cells in the gland – follicular cells (the majority) and parafollicular cells – secrete, respectively, the iodine-containing hormones THYROXINE (T4) and TRI-IODOTHYRONINE (T3), and the hormone CALCITONIN. T3 and T4 help control metabolism and calcitonin, in conjunction with parathyroid hormone (see above), regulates the body’s calcium balance. De?ciencies in thyroid function produce HYPOTHYROIDISM and, in children, retarded development. Excess thyroid activity causes thyrotoxicosis. (See THYROID GLAND, DISEASES OF.)... endocrine glands

Numerous glands within the tarsal plates of the eyelids. Their secretions form part of the tears. (See EYE.)... meibomian glands

The minute glands situated alongside hairs and opening into the follicles of the latter a short distance below the point at which the hairs emerge on the surface. These glands secrete an oily material, and are especially large upon the nose, where their openings form pits that are easily visible. In the mouth the glands open directly on the mucosal surface. (See also SKIN.)... sebaceous glands

See SKIN.... sweat glands

Lymphadenitis. Non-infectious. Can be localised, e.g. armpit only, due to lymphatic drainage of a local inflammation or generalised due to systemic infection (AIDS) or some malignant conditions.

Symptoms. Swelling of glands of armpit, neck and groin.

Alternatives. Tea: combine equal parts: Clivers, Red Clover, Gotu Kola. 2 teaspoons to each cup boiling water; infuse 15 minutes. Dose: half-1 cup thrice daily.

Decoction. Formula. Equal parts, Yellow Dock, Plantain, Clivers, Liquorice root, 1oz to 1 pint water gently simmered 20 minutes. Half a cup thrice daily.

Powders. Formula. Bayberry 1; Echinacea 2; Poke root half; a trace of Cayenne. Dose: 500mg (two 00 capsules or one-third teaspoon) thrice daily.

Tinctures. Combine equal parts: Poke root and Echinacea. One 5ml teaspoon in water thrice daily.

Poke root. A leading remedy for the condition.

Agnus Castus. Swollen glands in young girls.

Dr Finlay Ellingwood: Liquid Extracts: equal parts, Blue Flag root and Poke root. 30-60 drops in water thrice daily.

Diet. See: DIET – GENERAL. See: LYMPHATICS. ... glands – swollen

A pair of oval, peasized glands whose ducts open into the vulva (the folds of flesh that surround the opening of the vagina). During sexual arousal, these glands secrete a fluid to lubricate the vulval region. Infection of the glands causes bartholinitis.... bartholin’s glands

Two small glands opening either side of the external vaginal ori?ce. Their secretions help to lubricate the vulva, when a woman is sexually aroused. The glands may become infected and very painful; sometimes an abscess develops and local surgery is required. Otherwise antibiotics, analgesics and warm baths are usually e?ective.... bartholin’s glands

Also known as the bulbourethral glands, these are a pair of glands whose ducts open into the urethra at the base of the PENIS. They secrete a ?uid that is one of the constituents of the SEMEN which carries the spermatozoa and is ejaculated into the VAGINA during coitus (sexual intercourse).... cowper’s glands

A unicellular gland in cestodes, which encircles the ootype. Its function is not known.... mehlis’s glands

The glands which provide substances for the development of the egg and the formation of the shell in trematodes and cestodes.... vitelline glands

Traps in the lymphatic system that collect byproducts of body infection and which support the immune system in its role as body protector. ... lymph glands

The largest of the 3 pairs of salivary glands.

The parotid glands lie above the angle of the jaw, below and in front of the ear, on each side of the face.... parotid glands

compound glands of the small intestine, found in the *duodenum and the upper part of the jejunum. They are embedded in the submucosa and secrete mucus. [J. C. Brunner (1856–1927), Swiss anatomist]... brunner’s glands

small glands in the mucous membrane lining the mouth. They secrete material that mixes with saliva.... buccal glands

see Cowper’s glands.... bulbourethral glands

(bulbourethral glands) a pair of small glands that open into the urethra at the base of the penis. Their secretion contributes to the seminal fluid, but less than that of the prostate gland or seminal vesicles. [W. Cowper (1660–1709), English surgeon]... cowper’s glands

tubular glands that lie in the mucous membrane of the stomach wall. There are three varieties: the cardiac, parietal (oxyntic), and pyloric glands, and they secrete *gastric juice.... gastric glands

(crypts of Lieberkühn) simple tubular glands in the mucous membrane of the *intestine. In the small intestine they lie between the villi. They are lined with columnar *epithelium in which various types of secretory cells are found. In the large intestine Lieberkühn’s glands are longer and contain more mucus-secreting cells. [J. N. Lieberkühn (1711–56), German anatomist]... lieberkühn’s glands

modified sebaceous glands on the inner surface of the *prepuce.... preputial glands

see meibomian glands.... tarsal glands

the two pairs of glands that open at the junction of the vagina and vulva. The more posterior of the two are the greater vestibular glands (Bartholin’s glands); the other pair are the lesser vestibular glands. Their function is to lubricate the entrance to the vagina during coitus.... vestibular glands