The most conspicuous components of the female external genitalia are the labia majora. The labia majora consists of two large, rounded folds supported by adipose tissue. These structures are covered with pubic hair in post pubertal women. Between the labia is an area called the vestibule where the urethral and vaginal orifices as well as the clitoris can be found. The clitoris contains erectile tissue and becomes engorged with blood during sexual arousal.
The vagina extends from the cervix of the uterus to the vaginal orifice in the vestibule. It is approximately 10 cm long and has three functions:
1) it is the female organ of copulation and receives the male penis during intercourse
2) it is the birth canal
3) it provides a channel for the monthly menstrual flow.
The vagina ends at the cervix of the uterus. The cervix is the outlet of the uterus through which the fetus passes during the birth process. The uterus (also known as the womb) is a pear-shaped organ about 7.5 cm long, 5 cm wide and 3.0 cm thick. These dimensions apply to the non-pregnant uterus. During pregnancy, it will be much larger.
The walls of the uterus are divided into layers. The first layer, starting from the inside, is the endometrium which undergoes the changes associated with the menstrual cycle and it is this layer that is sloughed off during menstruation.
Extending from the uterus to the ovaries are the uterine or fallopian tubes. These tubes are about 10 cm long. They conduct the egg from the ovary to the uterus. The ovaries produce the key female sex steroids, estrogen, and progesterone as well as the ovum (eggs).
The production of eggs occurs in a cyclic pattern with increasing and decreasing hormone levels as well as changes in the ovaries and uterus, repeating itself about every 28 days. The cycle begins on the first day of menstrual flow or menses. The culminating event in the cycles is release of the ovum (ovulation), which typically occurs on day 14 in a typical 28-day cycle. Note that not all cycles are exactly 28 days and there can be differences between women, and even differences from one cycle to the next in the same woman.
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