The function of the gonads (sex glands) in both males and females is to produce the reproductive cells, the gametes, and to produce hormones. The gametes are generated by meiosis, a process of cell division that halves the chromosome number from 46 to 23. When male and female gametes unite in fertilization, the original chromosome number is restored. The sex hormones aid in the manufacture of the gametes, function in pregnancy and lactation, and also produce the secondary sex characteristics such as the typical size, shape, body hair, and voice that we associate with the male and female genders. The reproductive tract develops in close association with the urinary tract. In females, the two systems become completely separate, whereas the male reproductive and urinary tracts share a common passage, the urethra. Thus, the two systems are referred to together as the genitourinary (GU) or urogenital (UG) tract, and urologists are called on to treat disorders of the male reproductive system as well as of the urinary system.
► THE TESTES
The male germ cells, the spermatozoa (sperm cells), are produced in the paired testes (singular, testis) that are suspended outside of the body in the scrotum. Although the testes develop in the abdominal cavity, they normally descend through the inguinal canal into the scrotum before birth or shortly thereafter. From puberty on, spermatozoa form continuously within the testes in coiled seminiferous tubules. Their development requires the aid of special Sertoli cells and male sex hormones, or androgens, mainly testosterone.
These hormones are manufactured in interstitial cells located between the tubules. In both males and females, the gonads are stimulated by the hormones follicle stimulating hormone (FSH) and luteinizing hormone (LH), released from the anterior pituitary gland beneath the brain. Although these hormones are the same in both males and females, LH is called interstitial cell-stimulating hormone (ICSH) in males.
► FORMATION OF SEMEN
Semen is the thick, whitish fluid in which spermatozoa are transported. It contains, in addition to sperm cells, secretions from three types of accessory glands. The first of these, the paired seminal vesicles, release their secretions into the ejaculatory duct. The second, the prostate gland, secretes into the first part of the urethra beneath the bladder. As men age, enlargement of the prostate gland may compress the urethra and cause urinary problems. The two bulbourethral (Cowper) glands secrete into the urethra just below the prostate gland. Together these glands produce a slightly alkaline mixture that nourishes and transports the sperm cells and also protects them by neutralizing the acidity of the female vaginal tract.
► TRANSPORT OF SPERMATOZOA:
After their manufacture, sperm cells are stored in a much-coiled tube on the surface of each testis, the epididymis. Here they remain until ejaculation propels them into a series of ducts that lead out of the body. The first of these is the vas (ductus) deferens. This duct ascends through the inguinal canal into the abdominal cavity and travels behind the bladder. A short continuation, the ejaculatory duct, delivers the spermatozoa to the urethra as it passes through the prostate gland below the bladder. Finally, the cells, now mixed with other secretions, travel in the urethra through the penis to be released. The penis is the male organ that transports both urine and semen. It enlarges at the tip to form the glans penis, which is covered by loose skin, the prepuce or foreskin. Surgery is needed to remove the foreskin ,Wich is circumcision. This may be performed for medical reasons, but is most often performed electively in male infants for reasons of hygiene, cultural preferences, or religion.
The Female Reproductive System
► OVARIES
The female gonads are the paired ovaries (singular, ovary) that are held by ligaments in the pelvic cavity on either side of the uterus. It is within the ovaries that the female gametes, the eggs or ova (singular, ovum), develop. Every month several ova ripen, each within a cluster of cells called a graafian follicle. At the time of ovulation, usually only one ovum is released from the ovary and the remainder of the ripening ova degenerate. The follicle remains behind and continues to function for about 2 weeks if there is no fertilization of the ovum and for about 2 months if the ovum is fertilized.
► THE OVIDUCTS,
Uterus and Vagina After ovulation, the ovum travels into an oviduct (also called the uterine tube or fallopian tube), one of the two tubes attached to the upper lateral portions of the uterus. These tubes arch above the ovaries and have fingerlike projections (fimbriae) that sweep the released ovum into the oviduct. If fertilization occurs, it usually takes place in the oviduct. The uterus is the organ that nourishes the developing offspring. It is pear-shaped, with an upper rounded fundus, a triangular cavity, and a lower narrow cervix that projects into the vagina. The innermost layer of the uterine wall, the endometrium, has a rich blood supply. It receives the fertilized ovum and becomes part of the placenta during pregnancy. The endometrium is shed during the menstrual period if no fertilization occurs. The muscle layer of the uterine wall is the myometrium. The vagina is a muscular tube that receives the penis during intercourse, functions as a birth canal, and transports the menstrual flow out of the body.
► THE EXTERNAL GENITAL ORGANS:
All of the external female genital organs together are called the vulva. This includes the large outer labia majora and small inner labia minora that enclose the openings of the vagina and the urethra. The clitoris, anterior to the urethral opening, is similar in origin to the penis and responds to sexual stimulation. In both male and female, the region between the thighs, from the external genital organs to the anus, is the perineum. During childbirth, an incision may be made between the vagina and the anus to facilitate birth and prevent the tearing of tissue, a procedure called an episiotomy.
► Mammary Gland
The mammary glands, or breasts, are composed mainly of glandular tissue and fat. (((((( Their purpose is to provide nourishment for the newborn))))). . The milk secreted by the glands is carried in ducts to the nipple. The Menstrual Cycle: Reproductive activity in the female normally begins during puberty with menarche, the first menstrual period indicates that girl is matuar and she is ready to give birth.and from that time mensuration continue at Each month, the menstrual cycle is controlled, by hormones from the anterior pituitary gland. Follicle stimulating hormone (FSH) begins the cycle by causing the ovum to ripen in the graafian follicle. The follicle secretes estrogen, a hormone that starts development of the endometrium in preparation for the fertilized egg. A second pituitary hormone, luteinizing hormone (LH), triggers ovulation and conversion of the follicle to the corpus luteum. This structure, left behind in the ovary, secretes progesterone and estrogen, which further the growth of the endometrium. If no fertilization occurs, hormone levels decline, and the endometrium sloughs off in the process of menstruation. The average menstrual cycle lasts 28 days, with the first day of menstruation taken as day 1 and ovulation occurring on about day 14. Throughout the cycle, estrogen and progesterone feed back to the pituitary to regulate the production of FSH and LH. Family planning; Hormonal methods of birth control act by supplying estrogen and progesterone, which inhibit the pituitary and prevent ovulation, while not interfering with menstruation. Contraception: Contraception is the use of artificial methods to prevent fertilization of the ovum or its implantation in the uterus. Methods can be used to block sperm penetration of the uterus (condom, diaphragm), prevent implantation (intrauterine device [IUD]), or prevent ovulation (hormonal methods). Surgical sterilization for the male is a vasectomy; for the female, surgical sterilization is a tubal ligation, in which the fallopian tubes are cut and tied on both sides. The preferred method for performing this surgery is through the abdominal wall with a laparoscopes. Unprotective sexual intercourse is the major deseas causing factors of this system.so be careful. You can read this article in hausa by clicking here .and for any corrections or suggestions call me at or send to junaiduumar2233@gmail.com.
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