Human reproductive systemAll living things reproduce. This is something that sets the nale apart from non-living. Even though the reproductive system is essential to keeping a species alive, it is not essential to keeping an individual alive. This chapter describes the different anavar gives you energy of the female reproductive system: Reproduction can be defined as the process by which an organism continues its species.
Human Physiology/The female reproductive system - Wikibooks, open books for an open world
All living things reproduce. This is something that sets the living apart from non-living. Even though the reproductive system is essential to keeping a species alive, it is not essential to keeping an individual alive. This chapter describes the different parts of the female reproductive system: Reproduction can be defined as the process by which an organism continues its species.
In the human reproductive process, two kinds of sex cells gametes , are involved: These two gametes meet within the female's uterine tubes located one on each side of the upper pelvic cavity, and begin to create a new individual.
The female needs a male to fertilize her egg; she then carries offspring through pregnancy and childbirth. The reproductive systems of the male and female have some basic similarities and some specialized differences. They are the same in that most of the reproductive organs of both sexes develop from similar embryonic tissue, meaning they are homologous.
Both systems have gonads that produce sperm and egg or ovum and sex organs. And both systems experience maturation of their reproductive organs, which become functional during puberty as a result of the gonads secreting sex hormones.
The differences between the female and male reproductive systems are based on the functions of each individual's role in the reproduction cycle. A male who is healthy, and sexually mature, continuously produces sperm. The development of women's "eggs" are arrested during fetal development. This means she is born with a predetermined number of oocytes and cannot produce new ones.
At about 5 months gestation, the ovaries contain approximately six to seven million oogonia, which initiate meiosis. The oogonia produce primary oocytes that are arrested in prophase I of meiosis from the time of birth until puberty. After puberty, during each menstrual cycle, one or several oocytes resume meiosis and undergo their first meiotic division during ovulation. This results in the production of a secondary oocyte and one polar body.
The meiotic division is arrested in metaphase II. Fertilization triggers completion of the second meiotic division and the result is one ovum and an additional polar body.
The ovaries of a newborn baby girl contain about one million oocytes. This number declines to , to , by the time puberty is reached.
On average, oocytes are ovulated during a woman's reproductive lifetime. When a young woman reaches puberty around age 10 to 13, a promary oocyte is discharged from one of the ovaries every 28 days.
This continues until the woman reaches menopause, usually around the age of 50 years. Occytes are present at birth, and age as a woman ages. The external female genitalia is referred to as vulva. It consists of the labia majora and labia minora while these names translate as "large" and "small" lips, often the "minora" can protrude outside the "majora" , mons pubis, clitoris, opening of the urethra meatus , vaginal vestibule, vestibular bulbs, vestibular glands.
The term "vagina" is often improperly used as a generic term to refer to the vulva or female genitals, even though - strictly speaking - the vagina is a specific internal structure and the vulva is the exterior genitalia only. Calling the vulva the vagina is akin to calling the mouth the throat.
The mons veneris , Latin for "mound of Venus" Roman Goddess of love is the soft mound at the front of the vulva fatty tissue covering the pubic bone. It is also referred to as the mons pubis. The mons veneris protects the pubic bone and vulva from the impact of sexual intercourse. After puberty, it is covered with pubic hair, usually in a triangular shape. Heredity can play a role in the amount of pubic hair an individual grows. The labia majora are the outer "lips" of the vulva.
They are pads of loose connective and adipose tissue, as well as some smooth muscle. The labia majora wrap around the vulva from the mons pubis to the perineum. The labia majora generally hides, partially or entirely, the other parts of the vulva. There is also a longitudinal separation called the pudendal cleft. These labia are usually covered with pubic hair. The color of the outside skin of the labia majora is usually close to the overall color of the individual, although there may be some variation.
The inside skin is usually pink to light brown. They contain numerous sweat and oil glands. It has been suggested that the scent from these oils are sexually arousing. Medial to the labia majora are the labia minora. The labia minora are the inner lips of the vulva. They are thin stretches of tissue within the labia majora that fold and protect the vagina, urethra, and clitoris. The appearance of labia minora can vary widely, from tiny lips that hide between the labia majora to large lips that protrude.
There is no pubic hair on the labia minora, but there are sebaceous glands. The two smaller lips of the labia minora come together longitudinally to form the prepuce, a fold that covers part of the clitoris. The labia minora protect the vaginal and urethral openings. Both the inner and outer labia are quite sensitive to touch and pressure. The clitoris , visible as the small white oval between the top of the labia minora and the clitoral hood, is a small body of spongy tissue that functions solely for sexual pleasure.
Only the tip or glans of the clitoris shows externally, but the organ itself is elongated and branched into two forks, the crura, which extend downward along the rim of the vaginal opening toward the perineum.
Thus the clitoris is much larger than most people think it is, about 4" long on average. The clitoral glans or external tip of the clitoris is protected by the prepuce, or clitoral hood, a covering of tissue similar to the foreskin of the male penis.
However, unlike the penis, the clitoris does not contain any part of the urethra. During sexual excitement, the clitoris erects and extends, the hood retracts, making the clitoral glans more accessible.
The size of the clitoris is variable between women. On some, the clitoral glans is very small; on others, it is large and the hood does not completely cover it. The opening to the urethra is just below the clitoris. Although it is not related to sex or reproduction, it is included in the vulva. The urethra is actually used for the passage of urine. The urethra is connected to the bladder. In females the urethra is 1. Because the urethra is so close to the anus, women should always wipe themselves from front to back to avoid infecting the vagina and urethra with bacteria.
This location issue is the reason for bladder infections being more common among females. The hymen is a thin fold of mucous membrane that separates the lumen of the vagina from the urethral sinus. Sometimes it may partially cover the vaginal orifice. The hymen is usually perforated during later fetal development. Because of the belief that first vaginal penetration would usually tear this membrane and cause bleeding, its "intactness" has been considered a guarantor of virginity.
However, the hymen is a poor indicator of whether a woman has actually engaged in sexual intercourse because a normal hymen does not completely block the vaginal opening. The normal hymen is never actually "intact" since there is always an opening in it.
Furthermore, there is not always bleeding at first vaginal penetration. The blood that is sometimes, but not always, observed after first penetration can be due to tearing of the hymen, but it can also be from injury to nearby tissues.
A tear to the hymen, medically referred to as a "transection," can be seen in a small percentage of women or girls after first penetration. A transection is caused by penetrating trauma.
Masturbation and tampon insertion can, but generally are not forceful enough to cause penetrating trauma to the hymen. Therefore, the appearance of the hymen is not a reliable indicator of virginity or chastity. The perineum is the short stretch of skin starting at the bottom of the vulva and extending to the anus. It is a diamond shaped area between the symphysis pubis and the coccyx. This area forms the floor of the pelvis and contains the external sex organs and the anal opening.
It can be further divided into the urogenital triangle in front and the anal triangle in back. The perineum in some women may tear during the birth of an infant and this is apparently natural. Some physicians however, may cut the perineum preemptively on the grounds that the "tearing" may be more harmful than a precise cut by a scalpel. If a physician decides the cut is necessary, they will perform it.
The cut is called an episiotomy. The vagina is a muscular, hollow tube that extends from the vaginal opening to the cervix of the uterus. It is situated between the urinary bladder and the rectum. It is about three to five inches long in a grown woman. The muscular wall allows the vagina to expand and contract. The muscular walls are lined with mucous membranes, which keep it protected and moist.
A thin sheet of tissue with one or more holes in it, called the hymen, partially covers the opening of the vagina. The vagina receives sperm during sexual intercourse from the penis.
The sperm that survive the acidic condition of the vagina continue on through to the fallopian tubes where fertilization may occur. The vagina is made up of three layers, an inner mucosal layer, a middle muscularis layer, and an outer fibrous layer.