Gonads Health Dictionary

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Gonads: From 1 Different Sources

The sex glands – the testes in men and the ovaries in women.
Health Source: BMA Medical Dictionary
Author: The British Medical Association

Hypogonadism

A condition characterised by underactivity of the testes (see TESTICLE) or OVARIES – the gonads. The condition may be caused by a genetically based disorder resulting in an abnormally functioning gonad (primary hypogonadism) or by a malfunctioning PITUITARY GLAND that fails to produce an adequate amount of gonadotrophin hormone (see GONADOTROPHINS) – secondary hypogonadism. Those affected may fail to develop adequately the secondary characteristics of their sex: males will have delayed puberty, erectile impotence and infertility and also develop GYNAECOMASTIA; females also have delayed puberty, infertility, and sometimes HIRSUTISM.... hypogonadism

Corticosteroids

Natural steroid hormones or synthetic analogues, usually taken for suppressing inflammation (and immunity) and therefore having cortisone-like functions, or taken as analogues to adrenocortical androgen...or even testosterone, in order to impress the other gym members, make varsity by your junior year or to join the WWF and get newbie-mangled for two years by The Hangman or even the Hulkster Himself. Then, if your gonads don’t fall off and your back holds up you get promoted to Good Guy, have your chance to Take A Name and finally wear your chosen costume...a spandex violet nurse’s uniform.... corticosteroids

Gonadotrophins

Gonadotrophins, or gonadotrophic hormones, are hormones that control the activity of the gonads (i.e. the testes and ovaries). In the male they stimulate the secretion of TESTOSTERONE and the production of spermatozoa (see SPERMATOZOON); in the female they stimulate the production of ova (see OVUM) and the secretion of OESTROGENS and PROGESTERONE. There are two gonadotrophins produced by the PITUITARY GLAND. CHORIONIC GONADOTROPHIC HORMONE is produced in the PLACENTA and excreted in the urine.... gonadotrophins

Hermaphrodite

An individual in whom both ovarian (see OVARIES) and testicular (see TESTICLE) tissue is present. Hermaphrodites may have a testis on one side and an ovary on the other; or an ovotestis on one side and an ovary or testis on the other; or there may be an ovotestis on both sides. Both gonads are usually intra-abdominal. The true hermaphrodite usually has a UTERUS and at least one Fallopian tube (see FALLOPIAN TUBES) on the side of the ovary, and on the side of the testis there is usually a VAS DEFERENS. Most true hermaphrodites are raised as males, but external virilisation is not usually complete. Even when signi?cant phallic development is present, HYPOSPADIAS and CRYPTORCHIDISM are common. At puberty, GYNAECOMASTIA develops and MENSTRUATION is common, as ovarian function is usually more nearly normal than testicular function. The condition is rare. A more common condition is pseudohermaphroditism: these are individuals who possess the gonads of only one sex but whose external genitalia may be ambiguous. The cause is a hormonal imbalance and can usually be corrected by hormone treatment.... hermaphrodite

Impotence

Inability of the male to perform the sexual act. It may be partial or complete, temporary or permanent. Psychological factors are the most common cause and these include anxiety, ignorance, fear, guilt, weakness of sexual desire or abnormality of such desire. Counselling or sex therapy, preferably with the partner, has a 50-per-cent chance of helping to cure long-term impotence of psychological origin. Among organic causes are lesions (see LESION) of the external genitalia; disturbances of the ENDOCRINE GLANDS, such as diminished activity of the gonads, thyroid gland or pituitary gland; diseases of the central NERVOUS SYSTEM; any severe disturbance of health, such as DIABETES MELLITUS; and addiction to alcohol.

An oral drug for treating erectile function is sildena?l citrate (Viagra®), the ?rst in a new class of drugs called phosphodiesterase type 5 inhibitors, also including tadala?l (Cialis®) and vardena?l (Levitra®). They work by improving blood ?ow to the penis. They can be taken an hour before intercourse (up to 12 hours before, in the case of tadala?l). These drugs are not aphrodisiacs, and side-effects include headache, facial ?ushing and indigestion. There are some suggestions that they may affect retinal function.

Intracavernosal injection or urethral application of alprostadil, a drug which increases local blood supply to the penis, has been used for some years under medical supervision, but success has been variable and oral sildena?l seems to be a more convenient and e?ective treatment for a man with this disorder.... impotence

Infantilism

The condition characterised by imperfect sexual development at puberty. It may or may not be associated with small stature, and may be due to lack of development of certain of the ENDOCRINE GLANDS: for example, the gonads, pituitary gland or adrenal glands. In other cases it may be associated with a generalised disease such as diabetes mellitus, asthma, ulcerative colitis and rheumatoid arthritis (for more information, see under separate entries).... infantilism

Pseudohermaphrodite

A person in whom the gonads (testes or ovaries

– see GONAD) of only one sex are present in the body but in whom the external GENITALIA may not be obviously male or female. The condition is a result of a hormonal imbalance and can normally be treated by appropriate surgery and hormone drugs. (See also HERMAPHRODITE.)... pseudohermaphrodite

Endocrine Glands

Ductless glands that secrete chemicals (hormones) direct into the blood stream to be borne to other parts of the body. Chiefly: pituitary gland, thyroid gland, parathyroid gland, adrenal glands. The gonads are also endocrines, producing sex hormones. Similarly, the pancreas secretes insulin which is discharged directly into the blood. Certain herbs act specifically on these glands as normalisers (adaptogens): Ginseng, Gotu Kola, Echinacea, Liquorice, Wild Yam, etc. ... endocrine glands

Hermaphroditism

A congenital disorder in which gonads of both sexes are present, and the external genitalia are not clearly male or female.

True hermaphroditism is extremely rare and its cause unknown.

A more common condition is pseudohermaphroditism, in which the gonads of only 1 sex are present, but the external genitalia are not clearly either male or female.... hermaphroditism

Hypergonadism

Overactivity of the gonads (testes or ovaries) that results in overproduction of androgen hormones or oestrogen hormones.

Hypergonadism may be due to disorders of the gonads or a disorder of the pituitary gland that results in overproduction of gonadotrophin hormones.

During childhood, the condition causes precocious sexual development and excessive growth.... hypergonadism

Meiosis

Meiosis, or reduction division, is the form of cell division that only occurs in the gonads (see GONAD) – that is, the testis (see TESTICLE) and the ovary (see OVARIES) – giving rise to the germ cells (gametes) of the sperms (see SPERMATOZOON) and the ova (see OVUM).

Two types of sperm cells are produced: one contains 22 autosomes and a Y sex chromosome (see SEX CHROMOSOMES); the other, 22 autosomes and an X sex chromosome. All the ova, however, produced by normal meiosis have 22 autosomes and an X sex chromosome.

Two divisions of the NUCLEUS occur (see also CELLS) and only one division of the chromosomes, so that the number of chromosomes in the ova and sperms is half that of the somatic cells. Each chromosome pair divides so that the gametes receive only one member of each pair. The number of chromosomes is restored to full complement at fertilisation so that the zygote has a complete set, each chromosome from the nucleus of the sperm pairing up with its corresponding partner from the ovum.

The ?rst stage of meiosis involves the pairing of homologous chromosomes which join together and synapse lengthwise. The chromosomes then become doubled by splitting along their length and the chromatids so formed are held together by centromeres. As the homologous chromosomes – one of which has come from the mother, and the other from the father – are lying together, genetic interchange can take place between the chromatids and in this way new combinations of GENES arise. All four chromatids are closely interwoven and recombination may take place between any maternal or any paternal chromatids. This process is known as crossing over or recombination. After this period of interchange, homologous chromosomes move apart, one to each pole of the nucleus. The cell then divides and the nucleus of each new cell now contains 23 and not 46 chromosomes. The second meiotic division then occurs, the centromeres divide and the chromatids move apart to opposite poles of the nucleus so there are still 23 chromosomes in each of the daughter nuclei so formed. The cell divides again so that there are four gametes, each containing a half number (haploid) set of chromosomes. However, owing to the recombination or crossing over, the genetic material is not identical with either parent or with other spermatozoa.... meiosis

Pituitary

An endocrine gland somewhat behind the eyes and suspended from the front of the brain. The front section, the anterior pituitary, makes and secretes a number of controlling hormones that affect the rate of oxidation; the preference for fats, sugars, or proteins for fuel; the rate of growth and repair in the bones, connective tissue, muscles, and skin; the ebb and flow of steroid hormones from both the gonads and adrenal cortices. It does this through both negative and positive feedback. The hypothalamus controls these functions, secreting its own hormones into a little portal system that feeds into the pituitary, telling the latter what and how much to do. The hypothalamus itself synthesizes the nerve hormones that are stored in the posterior pituitary, which is responsible for squirting them into the blood when the brain directs it to. These neurohormones act quickly, like adrenalin, to constrict blood vessels, limit diuresis in the kidneys, and trigger the complex responses of sexual excitation, milk let­down in nursing, and muscle stimulus in the uterus (birthing, orgasm, and menstrual contractions), prostate, and nipples.... pituitary

Pituitary Gland

Also known as the pituitary body and the hypophysis, this is an ovoid structure, weighing around 0·5 gram in the adult. It is attached to the base of the BRAIN, and lies in the depression in the base of the skull known as the sella turcica. The anterior part is called the adenohypophysis and the posterior part the neurohy-P pophysis. The gland is connected to the HYPOTHALAMUS of the brain by a stalk known as the hypophyseal or pituitary stalk.

The pituitary gland is the most important ductless, or endocrine, gland in the body. (See

ENDOCRINE GLANDS.) It exerts overall control of the endocrine system through the media of a series of hormones which it produces. The adenohypophysis produces trophic hormones (that is, they work by stimulating or inhibiting other endocrine glands) and have therefore been given names ending with ‘trophic’ or ‘trophin’. The thyrotrophic hormone, or thyroid-stimulating hormone (TSH), exerts a powerful in?uence over the activity of the THYROID GLAND. The ADRENOCORTICOTROPHIC HORMONE (ACTH) stimulates the cortex of the adrenal glands. GROWTH HORMONE, also known as somatotrophin (SMH), controls the growth of the body. There are also two gonadotrophic hormones which play a vital part in the control of the gonads: these are the follicle-stimulating hormone (FSH), and the luteinising hormone (LH) which is also known as the interstitial-cell-stimulating hormone (ICSH) – see GONADOTROPHINS. The lactogenic hormone, also known as prolactin, mammotrophin and luteotrophin, induces lactation.

The neurohypophysis produces two hormones. One is oxytocin, which is widely used because of its stimulating e?ect on contraction of the UTERUS. The other is VASOPRESSIN, or the antidiuretic hormone (ADH), which acts on the renal tubules and the collecting tubules (see KIDNEYS) to increase the amount of water that they normally absorb.... pituitary gland

Sex Determination

The factors that determine biological sex. The underlying determinants are the sex chromosomes which cause the differential development of the gonads in the embryo. In males, the testes then produce hormones that cause the male reproductive organs to

form. In the absence of these hormones, a female reproductive tract develops. At puberty, another surge of hormones produces secondary sexual characteristics.

Chromosomal abnormalities or hormonal defects can lead to ambiguous sex (see genitalia, ambiguous), although true hermaphroditism is rare.... sex determination

Adrenarche

n. the start of secretion of *androgens by the adrenal glands, occurring at around 6–7 years of age in girls and 7–8 in boys. It is usually determined by the measurement of urinary 17-ketosteroids rather than direct assay of the androgens themselves. Adrenal androgens are *dehydroepiandrosterone (DHEA), DHEA sulphate, and androstenedione. The age of adrenarche is unrelated to the age of *gonadarche. Premature adrenarche is usually manifested as the early appearance of pubic hair due to levels of the adrenal androgens equivalent to those found in puberty. It does not proceed to full puberty as the gonads do not become active.... adrenarche

Adrenoleukodystrophy

n. a genetically determined condition of neurological degeneration with childhood and adult forms. Inherited as an X-linked (see sex-linked) trait resulting in *demyelination, it is characterized by progressive *spastic paralysis of the legs, sensory loss, and cognitive impairment, associated with adrenal gland insufficiency and small gonads. The demonstration of a genetic defect in the metabolism of very long chain fatty acids aids diagnosis and has implications for future possible drug therapies. Prenatal diagnosis is possible.... adrenoleukodystrophy

Steroid Hormone

These are fats similar to, and usually synthesized from, cholesterol, starting with Acetyl-CoA, moving through squalene, past lanosterol, into cholesterol, and, in the gonads and adrenal cortex, back to a number of steroid hormones. Nearly all of the classic hormones are proteins or smaller peptides; they don’t get inside a cell (the membrane keeps them out); instead, they bind to, and initiate, cell changes from the outside. The exceptions are the thyroxines (from the thyroid) and the steroid hormones. They move into the cell, bind with receptors, and initiate changes in the way a cell regenerates itself or synthesizes new compounds. Because the steroid hormones stimulate cell growth, either by changing the internal structure or increasing the rate of proliferation, they are often called anabolic steroids. Estrogen, an ovarian steroid, when secreted into the bloodstream, will be bound within a short time by internal receptors inside those cells that need estrogen for their growth; the unused portion is partially broken down, mostly in the liver, and partially stored in a less active form by adipose tissue. Since luteinizing hormone from the pituitary is surged in pulses an hour apart, the estrogen is also surged from the reacting ovaries, and by the time more estrogen is available, the binding cells need more; their program of synthesis has run out and needs to be started again. Of course, most steroid hormone reactions are less measured than this, but you get the idea.... steroid hormone

Testicle, Diseases Of

The SCROTUM may be affected by various skin diseases, particularly eczema (see DERMATITIS) or fungal infection. A HERNIA may pass into the scrotum. Defective development of the testicles may lead to their retention within the abdomen, a condition called undescended testicle.

Hydrocoele is a collection of ?uid distending one or both sides of the scrotum with ?uid. Treatment is by withdrawal of the ?uid using a sterile syringe and aspiration needle.

Hypogonadism Reduced activity of the testes or ovaries (male and female gonads). The result is impaired development of the secondary sexual characteristics (growth of the genitals, breast and adult hair distribution). The cause may be hereditary or the result of a disorder of the PITUITARY GLAND which produces GONADOTROPHINS that stimulate development of the testes and ovaries.

Varicocoele is distension of the veins of the spermatic cord, especially on the left side, the causes being similar to varicose veins elsewhere (see VEINS, DISEASES OF). The chief symptom is a painful dragging sensation in the testicle, especially after exertion. Wearing a support provides relief; rarely, an operation may be advisable. Low sperm-count may accompany a varicocele, in which case surgical removal may be advisable.

Orchitis or acute in?ammation may arise from CYSTITIS, stone in the bladder, and in?ammation in the urinary organs, especially GONORRHOEA. It may also follow MUMPS. Intense pain, swelling and redness occur; treatment consists of rest, support of the scrotum, analgesics as appropriate, and the administration of antibiotics if a de?nitive microorganism can be identi?ed. In some patients the condition may develop and form an ABSCESS.

Torsion or twisting of the spermatic cord is relatively common in adolescents. About half the cases occur in the early hours of the morning during sleep. Typically felt as pain of varying severity in the lower abdomen or scrotum, the testis becomes hard and swollen. Treatment consists of immediate undoing of the torsion by manipulation. If done within a few hours, no harm should ensue; however, this should be followed within six hours by surgical operation to ensure that the torsion has been relieved and to ?x the testes. Late surgical attention may result in ATROPHY of the testis.

Tuberculosis may occur in the testicle, especially when the bladder is already affected. Causing little pain, the infection is often far advanced before attracting attention. The condition generally responds well to treatment with a combination of antituberculous drugs (see also main entry for TUBERCULOSIS).

Tumours of the testes occur in around 600 males annually in the United Kingdom, and are the second most common form of malignant growth in young males. There are two types: SEMINOMA and TERATOMA. When adequately treated the survival rate for the former is 95 per cent, while that for the latter is 50 per cent.

Injuries A severe blow may lead to SHOCK and symptoms of collapse, usually relieved by rest in bed; however, a HAEMATOMA may develop.... testicle, diseases of

Adrenal Glands

Two organs situated one upon the upper end of each kidney. Each gland encloses a central part known as the medulla, and an outer cortex which exercises some control over sexual development. Addison’s Disease or tumours may cause defective hormone secretion and profoundly interfere with the metabolism of salt. Stresses of modern life may exhaust the glands.

The medulla, or core of the gland, secretes adrenalin and noradrenalin, known as the ‘fight or flight’ hormones that move the body into top gear to meet an emergency. Mental or physical stress may cause it to swing into action; increasing the heart beat, elevating blood pressure and releasing glycogen from the liver.

The cortex secretes a hormone – aldosterone (the salt and water hormone) which regulates water retention in the body. Also, the cortex secretes cortisone which raises the level of sugar in the blood . . . insulin reduces it. Also secreted are the adrenal sex hormones that complement the gonads.

Re-vitalisers for exhausted or hypoactive adrenals: Borage, Cayenne, Ginger root, Ginseng, Gotu Kola, Hawthorn, Liquorice, Mullein, Parsley root, Sarsaparilla, Wild Yam. ... adrenal glands

Blastema

n. any zone of embryonic tissue that is still differentiating and growing into a particular organ. The term is usually applied to the tissue that develops into the kidneys and gonads.... blastema

Gonadarche

n. the period during which the gonads begin to secrete sex hormones, so triggering puberty. The timing for this event is controlled by the pituitary gland; gonadarche occurs usually between the ages of 10 and 11 in girls and 11 and 12 in boys.... gonadarche

Gonadotrophin

(gonadotrophic hormone) n. any of several hormones synthesized and released by the pituitary gland that act on the testes or ovaries (gonads) to promote production of sex hormones and either sperm or ova. Their production is controlled by *gonadotrophin-releasing hormone. The main gonadotrophins are *follicle-stimulating hormone and *luteinizing hormone. They may be given by injection to treat infertility. See also human chorionic gonadotrophin.... gonadotrophin

Gubernaculum

n. (pl. gubernacula) either of a pair of fibrous strands of tissue that connect the gonads to the inguinal region in the fetus. In the male they guide and possibly move the testes into the scrotum before birth. In the female the ovaries descend only slightly within the abdominal cavity and the gubernacula persist as the round ligaments connecting the ovaries and uterus to the abdominal wall.... gubernaculum

Mesoderm

n. the middle *germ layer of the early embryo. It gives rise to cartilage, muscle, bone, blood, kidneys, gonads and their ducts, and connective tissue. It separates into two layers – an outer somatic and an inner splanchnic mesoderm, separated by a cavity (coelom) that becomes the body cavity. The dorsal somatic mesoderm becomes segmented into a number of *somites. See also mesenchyme. —mesodermal adj.... mesoderm

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