The Structure and Function of Female Sex Organs
Posted on November 7, 2007
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The reproductive organs of the female – the vagina, ovaries, fallopian tubes, and uterus.
Serve six purposes -
• They provide a receptacle for the male semen.
• They produce the ovum (egg cell).
• They serve as a meeting place for sperm and egg.
• They furnish a safe and secure site for the fertilized ovum to develop into a fetus.
• They manufacture chemicals, most notably estrogen and progesterone, essential for carrying out the female’s role in reproduction.
• They offer a source of sexual pleasure and satisfaction.
The Vagina
The vagina is the body cavity adapted to the reception of the semen.In actuality, the vagina is a potential cavity. Unless opened by the penis or by passage of an infant during birth, the front and rear walls are virtually next to each other. In the woman who has not had sexual intercourse with vaginal entry, the entrance to the vagina is generally closed in part by the hymen, a skinlike membrane that stretches across the vaginal entrance and contains one or more small openings. Normally the membrane is pierced at the initial sexual intercourse. However, the hymen is a highly variable structure, absent at birth in some female newborns and complete without any opening in others. It can be destroyed through activities other than intercourse, such as bicycle riding. The condition of the hymen cannot be considered as evidence of virginity or not.
The entrance to the vagina is guarded on either side by both a small and a large fold of skin, called the labia, or lips of the vagina. Since the inner pair is relatively small and the outer pair large, they are termed labia minora and majora. At the upper end of the vagina, just above the urethra from which the urine exits, is the clitoris. When unerected, it is usually about a half-inch in length, and when erected, almost twice as long. In its unerected state, a hood of skin covers the clitoris. The sole function of the clitoris is to react to sexual stimulation, enhancing the female’s pleasure and response.
Ovaries
The two ovaries, the size and shape of almonds, lie in the lower part of the abdominal cavity and produce the ova or egg cells. Normally one ovum matures each month. This process begins just before or soon after the first menses (menarche) and continues until the last (menopause), except during the nine months of pregnancy and a period of time thereafter. Usually only one of the ovaries matures an egg during each monthly cycle with no discernible plan. Sometimes they alternate, at other times the same ovary produces the ovum several months in succession. If one ovary is surgically removed, the remaining one takes over the complete job of egg production, maturing an ovum each month, usually with no reduction in fertilityThe ovary, like the male testicle, is an endocrine gland. It manufactures the two female hormones, estrogen and progesterone, in quantities that depend upon the phase of the monthly cycle. It also manufactures androgens, such as testosterone, although in much smaller quantities than are manufactured in the male. Most of these are changed to estrogens. The ovary produces another reproductive hormone, folliculostatin, also called inhibin. Inhibin suppresses or inhibits FSH, or follicle-stimulating hormone, produced by the pituitary gland.
The Fallopian Tubes
The two fallopian tubes, or oviducts, one on either side of the uterus, lead from the abdominal cavity near each ovary to the interior of the uterus. They are each approximately five inches long. They form the pathway for the upward swim of the spermatozoa and the downward journey of the ovum. The tubal canal, or channel, is constantly moist with secreted fluid, the amount of which increases significantly at the time of ovulation. The fallopian tube itself resembles a cornucopia. The wide bowl-like ovarian end is fringed with many fingerlike fimbria (see the drawing on page 9). During most of the monthly cycle, the fimbria are flaccid and inert. Just preceding ovulation, they become erect and constantly lick the surface of the adjacent ovary like hungry tongues seeking to sweep the surface of the freshly ruptured follicle and lick the egg into the open end of the tube. If by mischance the tiny egg is spilled into the abdominal cavity near the vicinity of the tube, the tube acts like a siphon and attempts to suck the spilled egg into it.
The Uterus
Finally, there is the pear-sized, pear-shaped two-to-three-ounce muscular uterus, enclosing a slitlike, highly distensible cavity. The lining of the cavity is called the endometrium. It is here that the fertilized ovum embeds or implants and the fetus develops. The uterus consists of two parts the corpus, or body, and the cervix. The corpus is the upper section. The top part of the corpus is called the fundus. The fallopian tubes attach to each side of the fundus, allowing the fertilized egg to enter the uterus. The cervix-the neck or mouth of the uterus-has a tiny opening, called the as. Before a woman has ever given birth, the os looks like a tiny dimple in the middle of the cervix. During birth, the os opens to allow passage of the baby. After a woman has given birth, the os will look more like a slit than a dimple.
During pregnancy the uterus will grow in weight from less than a quarter of a pound to almost three pounds. Its volume will increase from virtually nothing to about five quarts.
Tags:body cavity, egg cell, fallopian tubes, Female Anatomy, labia minora, ovum, reproductive organs, semen, sexual intercourse, sexual stimulation vagina
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