Female Reproductive System
June 17, 2008 · 7 Comments
A. External Structures:
- Mons Veneris/Pubis – Pad of fat which lies over the symphysis pubis where dark and curly hair grow in triangular shape that begins 1-2 years before the onset of menstruation. It protects the surrounding delicate tissues from trauma.
- Labia Majora – Two (2) lengthwise fatty folds of skin extending from mons veneris to the perineum that protect the labia minora, urinary meatus and vaginal orifice.
- Labia Minora – 2 thinner, lenghtwise folds of hairless skin extending from clitoris to fourchette.
- Glands in the labia minora lubricates the vulva
- Very sensitive because of rich nerve supply
- Space between the labia is called the Vestibule
- Clitoris – small, erectile structure at the anterior junction of the labia minora that contains more nerve endings. It is very sensitive to temperature and touch, and secretes a fatty substance called Smegma. It is comparable to the penis in it’s being extremely sensitive.
- Vestibule – the flattened smooth surface inside the labia. It encloses the openings of the urethra and vagina.
- Skene’s Glands/Paraurethral Glands – located just lateral to the urinary meatus on both sides. Secretion helps lubricate the external genital during coitus.
- Bartholin’s Gland/Vulvovaginal Glands – located lateral to the vaginal opening on both sides. It lubricates the external vulva during coitus and the alkaline pH of their secretion helps to improve sperm survival in the vagina.
- Fourchette – thin fold of tissue formed by the merging of the labia majora and labia minora below the vaginal orifice.
- Perineum – muscular, skin-covered space between the vaginal opening and the anus. It is easily stretched during childbirth to allow enlargement of vagina and passage of the fetal head. It contains the muscles (pubococcygeal and levator ani) which support the pelvic organs, the arteries that supply blood and the pudendal nerves which are important during delivery under anesthesia.
- Urethral meatus – external opening of the urethra. It contains the openings of the Skene’s glands which are often involved in the infections of the external genitalia.
- Vaginal Orifice/Introitus – external opening of the vagina, covered by a thin membrane called Hymen.
B. Internal Structures:
- Fallopian tube/Oviduct – 4 inches long from each side of the uterus (fundus). It transports the mature ova form the ovaries to the uterus and provide a place for fertilization of the ova by the sperm in it’s outer 3rd or outer half. Parts:
- Interstitial – lies within the uterine wall
- Isthmus – portion that is cut or sealed in a tubal ligation.
- Ampulla – widest, longest portion that spreads into fingerlike projections/fimbriae and it is where fertilization usually occurs.
- Infundibulum - rim of the funnel covered by fimbriated cells (hair covered fingerlike projections) that help to guide the ova into the fallopian tube.
- Ovaries – Oval, almond sized, dull white sex glands on either side of the uterus that measures 4 by 2 cm in diameter and 1.5 cm thick. It is responsible for the production, maturation and discharge of ova and secretion of estrogen and progesterone.
- Uterus – hollow, pear-shaped muscular organ, 3 inches long, 2 inches wide, weighing 50-60 grams held in place by broad and round ligaments, and abundant blood supply from the uterine and ovarian arteries. It is located in the lower pelvis, posterior to the bladder and anterior to the rectum. Organ of menstruation, site of implantation and provide nourishment to the products of conception.
- Perimetrium – outermost layer of the uterus comprised of connective tissue, it offers added strenght and support to the structure.
- Myometrium – middle layer, comprised of smooth muscles running in 3 directions; expels fetus during birth process then contracts around blood vessels to prevent hemorrhage.
- Endometrium – Inner layer which is visibly vascular and is shed during menstruation and following delivery.
Divisions of the Uterus:
- Fundus – upper rounded, dome-shaped portion that can be palpated to determine uterine growth during pregnancy and the force of contractions and for the assessment that the uterus is returning to it’s non-pregnant state following child birth.
- Corpus – body of the uterus.
- Isthmus – area between corpus and cervix which forms part of the lower uterine segment. It enlarges greatly to aid in accommodating the fetus. The portion that is cut when a fetus is delivered by a caesarian section.
- Cervix – lower cylindrical portion that represents 1/3 of the total uterus. Half of it lies above the vagina; half of it extends to the vagina. The cavity is termed the cervical canal. It has 2 openings/Os: internal os that open to the uterine cavity and the external os that opens to the vagina.
- Vagina – a 3-4 inch long dilatable canal located between the bladder and the rectum, it contains rugnae which permit considerable stretching without tearing. It acts as a organ of intercourse/copulation and passageway for menstrual discharges and fetus. Doderlein’s bacillus is the normal flora of the vagina which makes the pH of vagina acidic, detrimental to the growth of pathologic bacteria.