Spermatozoa Health Dictionary

The expulsion of SEMEN from the PENIS during ORGASM. The stimulation of sexual intercourse (coitus) or masturbation produces a spinal re?ex action that causes ejaculation. As well as containing spermatozoa (male germ cells), the semen comprises several constituents arising from COWPER’S GLANDS, the PROSTATE GLAND, the testicles and seminal vesicles (see TESTICLES) and these are discharged in sequence. (See also PREMATURE EJACULATION.)... ejaculation

Those embryonic cells with the potential to develop into ova (see OVUM) or spermatozoa (see SPERMATOZOON).... germ cell

Fluid produced by the male on ejaculation from the penis at sexual orgasm. Each ejaculate contains up to 500 million spermatozoa (male germ cells) suspended in a ?uid that is secreted by the PROSTATE GLAND, seminal vesicles (see TESTICLE), and Cowper’s glands – a pair of small glands (also called the bulbo-urethral glands) that open into the URETHRA at the base of the penis. Semen, or seminal ?uid, contains a form of sugar (fructose) essential for the motility of sperm. The hormone TESTOSTERONE is a key element in the production of sperm and of seminal ?uid.... semen

The production of mature sperm (see SPERMATOZOON) in the testis (see TESTICLE). The sperm cells originate from the outermost layer of the seminiferous tubules in the testis: these multiply throughout reproductive life and are transformed into mature spermatozoa, a process that takes up to 80 days.... spermatogenesis

(Plural: spermatozoa.) This is the male sex or germ cell which unites with the OVUM to form the EMBRYO or fetus. It is a highly mobile cell approximately 4 micrometres in length – much smaller than an ovum, which is about 35 micrometres in diameter. Each millilitre of SEMEN contains on average about 100 million spermatozoa, and the average volume of semen discharged during ejaculation in sexual intercourse is 2–4 ml. (Some recent research suggests that male fertility is falling because of a reduction in the production of viable spermatozoa – possibly due to environmental factors, including the discharge of hormones used for agricultural purposes and for human hormonal contraception.)

Once ejaculated during intercourse the spermatozoon travels at a rate of 1·5–3 millimetres a minute and remains mobile for several days after insemination, but quickly loses its potency for fertilisation. As it takes only about 70 minutes to reach the ovarian end of the uterine tube, it is assumed that there must be factors other than its own mobility, such as contraction of the muscle of the womb and uterine tube, that speed it on its way.... spermatozoon

Linn.

Family: Papilionaceae; Fabaceae.

Habitat: Throughout the country, ascending to an altitude of about 1,050 m in the outer Himalayas.

English: Indian Wild Liquorice, Jequirity, Crab's Eye, Precatory Bean.

Ayurvedic: Gunjaa, Gunjaka, Chirihintikaa, Raktikaa, Chirmi- ti, Kakanti, Kabjaka, Tiktikaa, Kaakananti, Kaakchinchi. (Not to be used as a substitute for liquorice.)

Unani: Ghunghchi, Ghamchi.

Siddha/Tamil: Kunri.

Folk: Chirmiti, Ratti.

Action: Uterine stimulant, abortifa- cient, toxic. Seeds—teratogenic. A paste of seeds is applied on vitiligo patches.

Along with other therapeutic applications, The Ayurvedic Pharmacopoeia of India has indicated the use of seeds in baldness.

Seeds contain abrin, a toxalbumin, indole derivatives, anthocyanins, ste- rols, terpenes. Abrin causes agglutination of erythrocytes, haemolysis and enlargement of lymph glands. A non- toxic dose of abrin (1.25 mcg/kg body weight), isolated from the seeds of red var., exhibited a noticeable increase in antibody-forming cells, bone marrow cellularity and alpha-esterase-positive bone marrow cells.

Oral administration of agglutinins, isolated from the seeds, is useful in the treatment of hepatitis and AIDS.

The seed extract exhibited antischis- tosomal activity in male hamsters.

The methanolic extract of seeds inhibited the motility of human spermatozoa.

The roots contain precol, abrol, gly- cyrrhizin (1.5%) and alkaloids—abra- sine and precasine. The roots also contain triterpenoids—abruslactone A, methyl abrusgenate and abrusgenic acid.

Alkaloids/bases present in the roots are also present in leaves and stems.

A. fruticulosus Wall. Ex Wight and Arn. synonym A. pulchellus Wall., A. laevigatus E. May. (Shveta Gunjaa) is also used for the same medicinal purposes as A. precatorius.

Dosage: Detoxified seed—1-3 g powder. Root powder—3-6 g. (API Vols. I, II.)... abrus precatorius

(Linn.) Willd.

Family: Mimosaceae.

Habitat: All over India, from the plains up to 900 m in the Himalayas; also in the Andamans.

English: Siris tree, East Indian walnut.

Ayurvedic: Shirisha, Bhandi, Bhandila, Shitapushpa, Mridu- pushpa, Kapitana (bark—dusty black).

Unani: Siras.

Siddha/Tamil: Vaagei.

Action: Antiseptic, antibacterial, antiallergic, antidermatosis, antidysenteric. Bark—used in bronchitis; bark and seeds in piles; root in hemicrania; flowers in cough, bronchitis, tropical pulmonary eosinophilia, and asthma. Pod— antiprotozoal.

Along with other therapeutic applications, The Ayurvedic Pharmacopoeia of India indicates the use of stembark in rhinitis, sinusitis and migraine.

Analysis of the plant revealed the presence of flavonoids, triterpenoids and triterpenoid saponins; oleano- lic acid, albigenic acid, albigenin and acacic acid. The bark contains 7-11% condensed tannin; also d-catechin and d-leucocyanidin.

Aqueous extract of the bark decreased histamine-induced broncho- spasm in guinea pigs.

Alcoholic extract of stembark contains cardenolide glycosides of digitox- in nature. It showed antidermatophyt- ic activity. Anthraquinone glycosides and its aglycone exhibited antibacterial activity.

A saponin from seeds exhibited spermicidal activity in animals. EtOH (50%) extract of pods was found to be spermicidal against rat and human spermatozoa at 2% concentration.

The therapeutic properties of Albizia julibrissin Durazz, Pink Siris, found in the outer Himalayas from the Indus eastwards to Sikkim, are the same as those of A. lebbeck.

Dosage: Stembark—3-6 g powder.

20-50 g for decoction. (API

Vol. III.)... albizia lebbeck

The general term for any one of a group of HORMONES which govern the development of the sexual organs and the secondary sexual characteristics of the male. TESTOSTERONE, the androgenic hormone formed in the interstitial cells of the testis (see TESTICLE), controls the development and maintenance of the male sex organs and secondary sex characteristics. In small doses it increases the number of spermatozoa (see SPERMATOZOON) produced, but in large doses it inhibits the gonadotrophic activity of the anterior PITUITARY GLAND and suppresses the formation of the spermatozoa. It is both androgenic and anabolic in action. The anabolic e?ect includes the ability to stimulate protein synthesis and to diminish the catabolism of amino acids, and this is associated with retention of nitrogen, potassium, phosphorus and calcium. Doses in excess of 10 mg daily to the female may produce VIRILISM.

Unconjugated testosterone is rarely used clinically because its derivatives have a more powerful and prolonged e?ect, and because testosterone itself requires implantation into the subcutaneous fat using a trocar and cannula for maximum therapeutic bene?t. Testosterone propionate is prepared in an oily solution, as it is insoluble in water; it is e?ective for three days and is therefore administered intramuscularly twice weekly. Testosterone phenyl-propionate is a long-acting microcrystalline preparation which, when given by intramuscular or subcutaneous injection, is e?ective for four weeks. Testosterone enantate is another long-acting intramuscular preparation. Mesterolone is an e?ective oral androgen and is less hepatoxic: it does not inhibit pituitary gonadotrophic production and hence spermatogenesis is unimpaired. Testosterone undecanoate is also an e?ective oral form.... androgen

The condition characterised by lack of spermatozoa (see SPERMATOZOON) in the SEMEN.... azoospermia

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

Ductus deferens, or VAS DEFERENS, is the tube which carries spermatozoa from the epidydimis to the seminal vesicles. (See TESTICLE.)... ductus deferens

Roxb.

Family: Asparagaceae.

Habitat: The western Himalayas and Punjab, from Himachal Pradesh to Kumaon, up to 1,500 m.

Ayurvedic: Mushali, (white var.), Mahaashataavari. The black variety is equated with Taalamuuli, Chlorophytum arundinaceum Baker.

Unani: Shaqaaqul-e-Hindi.

Action: A substitute for A. officinalis.

The root yields asparagin. Sapoge- nins A and B, isolated from the root, were identified as stigmasterol and sarsasapogenin.

Action: Diuretic, laxative, car- diotonic, sedative, galactagogue; used for neuritis and rheumatism, as well as for cystitis and pyelitis.

Key application: In irrigation therapy for inflammatory diseases of the urinary tract and for prevention of kidney stones. (German Commission E.). It is contraindicated in kidney diseases and oedema because of functional heart.

The root contains steroidal glyco- sides (asparagosides) and bitter glyco- sides; asparagusic acid and its derivatives; asparagines, arginine and ty- rosine; flavonoids, including rutin, kaempferol and quercetrin; polysac- carides and inulin. Asparagine is a strong diuretic source of folic acid and selenium.

A spirostanol glycoside, isolated from the methanolic extract of the fruits, has shown 100% immobilization of human spermatozoa.

Dosage: Root—3-5 g powder. (CCRAS.)... asparagus adscendens

A thin rubber or plastic sheath placed over the erect PENIS before sexual intercourse. It is the most e?ective type of barrier contraception and is also valuable in preventing the transfer between sexual partners of pathogenic organisms such as gonococci, which cause GONORRHOEA, and human immuno-de?ciency virus, which may lead to AIDS (see AIDS/HIV). Sheaths are most e?ective when properly used and with spermicides.

The female condom might be suitable for contraception when a woman misses a day or two of her contraceptive pill; if there is DYSPAREUNIA; when the perineum needs protection, for example, after childbirth; or in cases of latex allergy to traditional condoms. Used properly with spermicide, it provides an e?ective barrier both to infections and to spermatozoa. Failure may result if the penis goes alongside the condom, if it gets pushed up into the vagina, or if it falls out. (See CONTRACEPTION.)... condom

The process by which male and female gametes (spermatozoa and oöcytes respectively) fuse to form a zygote which develops, by a complex process of cell division and di?erentiation, into a new individual of the species. In humans, fertilisation occurs in the FALLOPIAN TUBES. Sperm deposited in the upper vagina traverse the cervix and uterus to enter the Fallopian tube. Many sperm attempt to penetrate the zona pellucida surrounding the oöcyte, but only one is able to penetrate the oöcyte proper and this prevents any other sperm from entering. Once the sperm has entered the oöcyte, the two nuclei fuse before the zygote begins to divide.... fertilisation

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

An immature OVUM. When the cell undergoes MEIOSIS in the ovary it becomes an ovum and is ready for fertilisation by the spermatozoa. Only a small number of the many oöcytes produced survive until PUBERTY, and not all of them will become ova and be ejected into the FALLOPIAN TUBES.... oöcyte

One of the small paired sacs lying on either side of the male URETHRA, which collect and store spermatozoa. (See TESTICLE.)... seminal vesicle

n. (pl. epididymides) a highly convoluted tube, about seven metres long, that connects the *testis to the vas deferens. The spermatozoa are moved passively along the tube over a period of several days, during which time they mature and become capable of fertilization. They are concentrated and stored in the lower part of the epididymis until ejaculation. —epididymal adj.... epididymis

Wall.

Family: Theaceae.

Habitat: Konkan and Western Ghats.

Folk: Miyili, Atangi, Ola, Nagette, Thorilla (Tamil Nadu).

Action: Leaves—stomachic, appetizer.

Leaves contain 0.04% alkaloid and tannic acid. The bark contains ellagic acid and coumarin.

English: Tree Cotton, Desi Cotton.

Ayurvedic: Kaarpaasi.

Siddha/Tamil: Sempartthi (Red Cotton), Sivappuparutthi.

Folk: Kapaasa.

Action: Seed—anticatarrhal (used in consumption), antigonorrhoeic (used in gleet and chronic cystitis). Root—febrifuge. Plant (especially leaf)—uterine stimulant.

The glands contain 35-50% gossy- pol, a polyphenolic toxic compound. Seeds contain 18.5-25.4% protein, 0.57-2.38% free gossypol. Gossypol is a male contraceptive. At an initial dose of 20 mg/day orally for 3 months, followed by 50-60 mg weekly maintenance dose, sperm motility is reduced initially as it inhibits important enzymes of metabolic pathways thus affecting availability of enzyme to spermatozoa. Subsequently sperm production is blocked.

Gossypol is reported to cause a transient weakness early in therapy, hy- pokalaemia and changes in ECG among other side effects.

Gossypol also assists menstrual flow and effectively inhibits eggs implantation.

Gossypol and its derivatives have been shown to have significant antimicrobial activity as well as wound healing effect. It is reported to kill herpes virus.... gordonia obtusa

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

Twins occur about once in 80 pregnancies, triplets once in 6,000, and quadruplets about once in 500,000. Quintuplets are exceedingly rare. Such is the natural state of a?airs.

In recent years, however, the position has been altered by the introduction of the so-called fertility drugs, such as CLOMIPHENE, and human menopausal gonadotrophin which, through the medium of the PITUITARY GLAND, stimulate the production of ova (see OVUM). Their wide use in the treatment of INFERTILITY has resulted in an increase in the number of multiple births, a recognised hazard of giving too large a dose.

Twins may be binovular or uniovular. Binovular, or fraternal, twins are the result of the mother’s releasing two ova within a few days of each other and both being fertilised by separate spermatozoa (see SPERMATOZOON). They both develop separately in the mother’s womb and are no more alike than is usual with members of the same family. They are three times as common as uniovular, or identical, twins, who are developed from a single ovum fertilised by a single spermatozoon, but which has split early in development. This is why they are usually so remarkably alike in looks and mental characteristics. Unlike binovular twins, who may be of the same or di?erent sex, they are always of the same sex.

So far as fraternal, or binovular, twins are concerned, multiple pregnancy may be an inherited tendency; it certainly occurs more often in certain families, but this may be partly due to chance. A woman who has already given birth to twins is ten times more likely to have another multiple pregnancy than one who has not previously had twins. The statistical chance of a third pair of twins is 1:512,000. Identical twins do not run in families.

The relative proportion of twins of each type varies in di?erent races. Identical twins have much the same frequency all over the world: around 3 per 1,000 maternities. Fraternal twins are rare in Mongolian races: less than 3 per 1,000 maternities. In Caucasians they occur two or three times as often as identical twins: between 7 (Spain and Portugal) and 10 (Czech and Slovak Republics and Greece) per 1,000 maternities. They are more common in Afro-Caribbeans, reaching 30 per 1,000 maternities in certain West African populations.

Rarely, uniovular twins may not develop as separate individuals, being physically joined in some way. They are called conjoined or (traditionally) Siamese twins. Depending on the extent of common structures shared by the infants – this ranges from a common umbilical cord to twins with conjoined heads or a common liver – the infants may be successfully separated by surgery. (See CONJOINED TWINS.)

Parents of twins, triplets, etc. can obtain advice and help from the Twins and Multiple Births Association (TAMBA).... multiple births

Every man has two testicles or testes which are the sexual glands. In the fetus, they develop in the abdomen, but before birth they descend into a fold or pouch of skin known as the SCROTUM. Each testicle consists of up to 1,000 minute tubes lined by cells from which the spermatozoa (see SPERMATOZOON) are formed. Around 4·5 million spermatozoa are produced per gram of testicle per day. These tubes communicate with one another near the centre of the testicle, and are connected by a much coiled tube, the EPIDIDYMIS, with the ductus, or VAS DEFERENS, which enters the abdomen and passes on to the base of the bladder. This duct, after joining a reservoir known as the seminal vesicle, opens, close to the duct from the other side of the body, into the URETHRA where it passes through the PROSTATE GLAND. Owing to the convolutions of these ducts leading from the testicles to the urethra, and their indirect route, the passage from testicle to urethra is over 6 metres (20 feet) in length. In addition to producing spermotozoa, the testicle also forms the hormone TESTOSTERONE which is responsible for the development of male characteristics.... testicle

n. 1. the study of male infertility and erectile dysfunction. *Seminal analysis reveals the presence of gross abnormalities in the shape and motility of spermatozoa, as well as their concentration in the semen, but further procedures are required to diagnose the underlying causes of the sperm dysfunction. These include the diagnosis of abnormalities in the genital tract (e.g. varicocele, obstruction of the vas deferens), which may be corrected surgically, and testing for the presence of antisperm antibodies in the semen and for the ability of the sperm to penetrate the cervical mucus, as well as for the presence of hormonal disorders. More sophisticated techniques include computer-assisted quantitative motility measurements, which monitor the precise speed and motility patterns of individual sperm; biochemical tests for the production of free oxygen radicals, which cause damage to developing sperm; and *acrosome-reaction assays, which reveal the ability of the sperm to penetrate the barriers surrounding the ovum. The development of all these techniques has enabled the identification of several previously undiagnosed causes of infertility and the selection of treatments most likely to succeed in remedying them. 2. the study of androgen production and the relationship of plasma androgen to androgen action. This study is necessary to understand *hirsutism and other conditions caused by abnormal androgen production.... andrology

n. the fusion of a spermatozoon and an ovum. Rapid changes in the membrane of the ovum prevent other spermatozoa from penetrating. Penetration stimulates the completion of meiosis and the formation of the second polar body. Once the male and female pronuclei have fused the zygote starts to divide by cleavage.... fertilization

n. (pl. flagella) a fine long whiplike thread attached to certain types of cell (e.g. spermatozoa and some unicellular organisms). Flagella are responsible for the movement of the organisms to which they are attached.... flagellum

(GIFT) a procedure for assisting conception, suitable only for women with healthy Fallopian tubes. In over 50% of women in whom infertility is diagnosed, the tubes are normal but some other factor, such as endometriosis, prevents conception. Using needle *aspiration, under laparoscopic or ultrasonic guidance, ova are removed from the ovary. After being mixed with the partner’s spermatozoa, they are introduced into a Fallopian tube, where fertilization takes place. The fertilized ovum can subsequently become implanted in the uterus.... gamete intrafallopian transfer

n. the process by which spermatozoa and ova are formed. In both sexes the precursor cells undergo *meiosis, which halves the number of chromosomes. However, the timing of events and the size and number of gametes produced are very different in the male and female. See oogenesis; spermatogenesis.... gametogenesis

combining form denoting origin or development. Example: spermatogenesis (development of spermatozoa).... genesis

(intracytoplasmic sperm injection) a technique of assisted conception that has revolutionized the treatment of severe male infertility. Spermatozoa are aspirated or extracted from the testis or epididymis (see MESA; PESA) and a single sperm is injected into the cytoplasm of a secondary *oocyte in vitro. The fertilized ovum is then implanted into the uterus.... icsi

(IUI) a procedure for assisting conception in which carefully washed spermatozoa are injected into the uterus through the vagina at the time of ovulation, which is induced and monitored (using ultrasound) to determine the day of insemination. This procedure is used in cases of male infertility due to inability of the sperm to penetrate the cervical mucus or the barriers surrounding the ovum, in which case the sperm may be treated in vitro to improve their motility and *acrosome reaction. IUI is also used for donor insemination.... intrauterine insemination

n. inability in a woman to conceive or in a man to induce conception after regular unprotected sexual intercourse for two years. Female infertility may be due to failure to ovulate, to obstruction of the *Fallopian tubes, or to disease of the lining of the uterus (endometrium). Possible treatments (depending on the cause) include administration of drugs (such as *clomifene or *gonadorelin analogues), surgery (see salpingography; salpingostomy; salpingolysis) to restore patency of the Fallopian tubes, *gamete intrafallopian transfer (GIFT), and *in vitro fertilization. Causes of male infertility include decreased numbers or motility of spermatozoa (see oligospermia) and total absence of sperm (see azoospermia). See also andrology; sterility.... infertility

(IVF) fertilization of an ovum outside the body, the resultant *zygote being incubated to the *blastocyst stage and then implanted in the uterus. The technique, pioneered in Britain, resulted in 1978 in the birth of the first test-tube baby. IVF may be undertaken when a woman has blocked Fallopian tubes, unexplained infertility, endometriosis, or ovulation disorders; it is also carried out for purposes of surrogacy and egg donation. The mother-to-be is given hormone therapy causing a number of ova to mature at the same time (see superovulation). Several of them are then removed from the ovary through a laparoscope. The ova are mixed with spermatozoa and incubated in a culture medium until the blastocyst is formed. The blastocyst is then implanted in the mother’s uterus and the pregnancy proceeds normally. IVF is regulated by the *Human Fertilisation and Embryology Act 1990 via the Human Fertilisation and Embryology Authority.... in vitro fertilization

(microsurgical epididymal sperm aspiration) the removal of spermatozoa from the epididymis by needle *aspiration. This procedure, performed under anaesthetic, may be undertaken to assist conception in cases where the normal passage of sperm from the testis is obstructed, for example by blockage (through infection) of the ducts or by vasectomy. The extracted sperm are subjected to special treatment to select the strongest and most motile; these are then chemically treated to activate them and used for in vitro fertilization (see ICSI).... mesa

n. the presence of either dead or motionless spermatozoa in the semen. See infertility.... necrospermia

n. a reduced number of spermatozoa in the semen (see seminal analysis). In oligospermia there are less than 20 million spermatozoa per ml with poor motility (asthenospermia) and often including many bizarre and immature forms (teratospermia). Treatment is directed to any underlying cause (such as *varicocele). See also andrology; infertility.... oligospermia

(percutaneous epididymal sperm aspiration) a method of assisted conception in which spermatozoa are removed directly from the *epididymis under local anaesthetic. The sperm are then used to fertilize egg cells in vitro (see ICSI).... pesa

a test used in the investigation of infertility. A specimen of cervical mucus, taken 6–24 hours after coitus, is examined under a microscope. The appearance of 10 or more progressively motile spermatozoa per high-power field in the specimen indicates that there is no abnormal reaction between spermatozoa and mucus. The test should be undertaken in the postovulatory phase of the menstrual cycle.... postcoital test

n. the paired sac that holds the testes and epididymides outside the abdominal cavity. Its function is to allow the production and storage of spermatozoa to occur at a lower temperature than that of the abdomen. Further temperature control is achieved by contraction or relaxation of muscles in the scrotum. —scrotal adj.... scrotum

analysis of a specimen of semen, which should be obtained after five days of abstinence from coitus, in order to assess male fertility. Normal values are as follows: volume of ejaculate: 2–6.5 ml; liquefaction complete in 30 minutes; sperm concentration: 20–200 million spermatozoa per ml (sperm count refers to the total number of spermatozoa in the ejaculate); motility: 60% moving progressively at 30 minutes to 3 hours; abnormal forms: less than 20%. Analysis of three separate specimens is necessary before confirming the presence of an abnormal result.... seminal analysis

n. a small cell produced as an intermediate stage in the formation of spermatozoa. Spermatids become embedded in *Sertoli cells in the testis. They are transformed into spermatozoa by the process of spermiogenesis (see spermatogenesis).... spermatid

n. a cell produced as an intermediate stage in the formation of spermatozoa (see spermatogenesis). Spermatocytes develop from spermatogonia in the walls of the seminiferous tubules of the testis; they are known as either primary or secondary spermatocytes according to whether they are undergoing the first or second division of meiosis.... spermatocyte

n. (pl. spermatogonia) a cell produced at an early stage in the formation of spermatozoa (see spermatogenesis). Spermatogonia first appear in the testis of the fetus but do not multiply significantly until after puberty. They act as stem cells in the walls of the seminiferous tubules, dividing continuously by mitosis and giving rise to *spermatocytes.... spermatogonium

n. the presence of spermatozoa in the urine. Spermatozoa are occasionally seen on microscopic examination of the urine and their presence is not abnormal. If present in large numbers, the urine becomes cloudy, usually towards the end of micturition. Abnormal ejaculation into the bladder on orgasm (retrograde ejaculation) may occur after *prostatectomy or other surgical procedures or in neurological conditions that destroy the ability of the bladder neck to close on ejaculation.... spermaturia

n. an agent that kills spermatozoa. Creams and jellies containing chemical spermicides are used – in conjunction with a *diaphragm – as contraceptives. —spermicidal adj.... spermicide

n. the process by which spermatids become mature spermatozoa within the seminiferous tubules of the testis. See spermatogenesis.... spermiogenesis

(Suzi) a method of assisting conception in cases of infertility caused by the inability of the spermatozoa to penetrate the barriers surrounding the ovum. Using *in vitro fertilization techniques, a small number of spermatozoa (no more than six) are injected through the *zona pellucida into the perivitelline space (which surrounds the egg membrane). If fertilization subsequently occurs, the blastocyst is implanted in the mother’s uterus.... subzonal insemination

n. the fertilization of two or more ova of the same age by spermatozoa from different males. See superfetation.... superfecundation

reducing the impact of complications and progression of established disease. Examples include *cardiac rehabilitation following myocardial infarction, stroke rehabilitation, and screening people with diabetes for diabetic *retinopathy. In practice, the distinction between tertiary and *secondary prevention is often unclear. See also preventive medicine; primary prevention.

TESA (testicular sperm aspiration) a technique used in the treatment of male infertility in which spermatozoa are removed by an incision into and aspiration from the testis. The sperm are then used to fertilize egg cells in vitro (see ICSI).... tertiary prevention

n. (pl. testes) either of the pair of male sex organs that produce spermatozoa and secrete the male sex hormone *androgen under the control of *gonadotrophins from the pituitary gland. The testes of the fetus form within the abdomen but descend into the *scrotum in order to maintain a lower temperature that favours the production and storage of spermatozoa. The bulk of the testis is made up of long convoluted seminiferous tubules (see illustration), in which the spermatozoa develop (see spermatogenesis). The tubules also contain *Sertoli cells, which may nourish developing sperm cells. Spermatozoa pass from the testis to the *epididymis to complete their development. The interstitial (Leydig) cells, between the tubules, are the major producers of androgens.... testis

n. the tube that conducts urine from the bladder to the exterior. The female urethra is quite short (about 3.5 cm) and opens just within the *vulva, between the clitoris and vagina. The male urethra is longer (about 20 cm) and runs through the penis. As well as urine, it receives the secretions of the male accessory sex glands (prostate and Cowper’s glands and seminal vesicles) and spermatozoa from the *vas deferens; thus it also serves as the ejaculatory duct.... urethra

(sing. vas efferens) the many small tubes that conduct spermatozoa from the testis to the epididymis. They are derived from some of the excretory tubules of the *mesonephros.... vasa efferentia

(pl. vasa deferentia) either of a pair of ducts that conduct spermatozoa from the *epididymis to the *urethra on ejaculation. It has a thick muscular wall the contraction of which assists in ejaculation.... vas deferens