FEMALE REPRODUCTIVE SYSTEM - Centennial Health



FEMALE REPRODUCTIVE SYSTEM

GONADS: Gonads are specialized cells that early in prenatal life will either develop into ovaries in females or testes in males depending on hormonal stimulation.

OVARIES: The ovaries develop by the 10th-11th week in the embryo near the kidney then move downward into the pelvis. The ovaries are almond shaped (1 inch wide, 1 ½ inches long and ¼ inch thick). They are pink in young women and gray, shrunken and wrinkled in older women.

• FUNCTION OF THE OVARIES:

1. Produce OVA (eggs)

2. Secrete the female hormone Estrogen

PRIMARY FOLLICLES: At birth the ovaries contain about 200,000-400,000 small sac like structures called Primary Follicles. Many degenerate (die) leaving around 1,000 at puberty. Of these, about 375-400 will develop into ova (eggs) over a women’s reproductive lifetime.

PUBERTY: Occurs between ages 11-14 and is when the female is made ready for reproduction.

The pituitary gland releases Follicle Stimulating Hormone (FSH) which causes the ovaries to release the female hormone ESTROGEN into the circulatory system. ESTROGEN – is responsible for the primary and secondary sexual characteristics in females.

• PRIMARY SEXUAL CHARACTERISTICS: the fallopian tubes, uterus, vagina all increase in size and maturity in order to reproduce

• SECONDARY SEXUAL CHARACTERISTICS:

1. Deposition of fat in the breast and the development of a duct system

2. Broadening of the pelvis- with fat deposits in the hips and thighs

3. Development of soft and smooth skin

4. Development of pubic hair with a flat upper border (a triangular border is characteristic of the male).

5. Long bones stop growing. In the absent of estrogen females usually grow taller than normal

CHANGES DURING PUBERTY: 2 important changes occur during puberty.

• OVULATION

• MENSTRUATION

OVUALTION: Is the release of a mature ovum(egg) from the ovary. Before ovulation occurs, though, the primary follicles in the ovary must undergo several changes.

• The primary follicles are stimulated to grow and reach maturity by 2 pituitary hormones, FSH (Follicle Stimulating Hormone) and LH (Luteinizing Hormone). Each month about 15-20 immature follicles start to grow but, only ONE will balloon outward and reach full maturity. This one follicle is called the GRAAFIAN FOLLICLE. On the surface of the Graaffian Follicle is a nipple –like protrusion called a STIGMA. Hormones cause the stigma to rupture the follicle and the ovum (egg) is released from the ovary. The other follicles that started to grow will degenerate (die).

A NEW OVUM (EGG): The newly released ovum is very fragile. It can only be fertilizes during the first 12-24 hours after it is released. To aid the ovum, the follicles that remain in the ovary are transformed in order to help it survive. They form a yellow glandular body called the CORPUS LUTEUM. The Corpus Luteum secretes two important hormones, ESTROGEN and PROGESTERONE to prepare the female reproductive system for the ovum (egg).

FALLOPIAN TUBE: Are trumpet-shaped tubes about 3-5 long that extend from the ovaries to the uterus. They are also called the “Uterine tubes” or “Oviducts.”

HOW THE OVUM (EGG) GETS INTO THE FALLOPIAN TUBE: Contractions of the walls of the fallopian tube create a suction that sweeps the ovum into the ends of the tubes through “finger” like projection called Fimbriae. Hair-like projections called CILIA found on the inner surfaces of the fallopian tubes also help this process.

• Ova on the right enter the right fallopian tube and those from the left enter the left tube.

• It usually takes 3-7 days for the ovum (egg) to reach the uterus.

WHERE FERTILIZATION OCCURS: Fertilization usually occurs in the upper 1/3 of the fallopian tube. Most females do not feel when ovulation occurs. We refer to this as “a silent trip”. In a few women a slight pain in the side may accompany ovulation.

THE UTERUS: The uterus or “womb” is a hollow muscular pouch located between the bladder and the rectum. It resembles a pear. It is about 3 inches long, 2 inches wide at the top, narrowing down to the cervix or neck which is about ½ to 1 inch in diameter.

CERVIX: if the uterus were an upside-down milk bottle, the neck of the bottle would be the cervix. During pregnancy the cervix retains the growing embryo.

UTERINE LAYERS: The uterus has 2 layers, the Myometrium, Endometrium

• MYOMETRIUM – the muscular layer of the uterus. When pregnancy is over, the arteries are kept from hemorrhaging by the constriction of these muscle fibers.

• ENDOMETRIUM – the innermost layer about 3-4 millimeters thick. It is a soft tissue with many blood vessels. This layer grows each month and is prepared to serve as a home for the fertilized egg.

NORMAL IMPLANTATION: If the egg is fertilized, it must form permanent connection in the uterus in order to develop into a full-term baby. Estrogen and Progesterone prepare the Endometrium (innermost layer) of the uterus for the fertilized egg. Progesterone prevents contraction of the muscular layer of the uterus the Myometrium so the egg will not be expelled. It also stimulates the development of ducts in the mother’s breast for breastfeeding. Estrogen is responsible for growth of the placenta, development of the fetus and is also aids in breast feeding. Both hormones remain high during pregnancy.

ECTOPIC PREGNANCY: When fertilization takes place in the fallopian tube. Because of shortage of space at this location, it is a medical emergency and must be surgically removed.

MENSTRUATION: If fertilization fails to take place the recurrent female cycle takes place. Menstru means “monthly” hence the term menstruation. The average menstrual cycle is 28 days and occurs in 3 phases:

1. FOLLICULAR PHASE- Starts on the first day of your period. FHS (Follicle Stimulating Hormone) and LH (Leutenizing Hormone) cause the growth of the follicle and production of estrogen.

2. OVULATION PHASE – starts about 14 days after the follicular phase. Is the midpoint of the cycle with the next menstrual period starting about 2 weeks later. LH (Leutenizing Hormone) increases causing the release of an ovum (egg) or ovulation. Cervical mucus production increases and thickens in order to capture the man’s sperm and move it towards the eggs.

3. LUTEAL PHASE – begins right after ovulation. Progesterone levels increase to maintain the growth of the endometrium. If fertilization has occurred progesterone levels will remain high and the egg will implant in the lining of the uterine wall. If fertilization does not occur, progesterone and estrogen levels drop and the endometrium breaks down and passes out of the body through the vagina. During menstruation, blood, fluid and the lining of the uterus are expelled. A menstrual period last about 3 to 5 days.

• Dysmenorrhea- painful menstruation or crampy abdominal pain. Causes may include inflammation, constipation, stress, fibroids, endometriosis, ovarian cysts, sexually transmitted diseases (STI’s) and premenstrual syndrome (PMS).

• PMS (Premenstrual Syndrome) – a medical condition that causes a variety of physical and psychological symptoms just before the menstrual period. The number and severity of symptoms vary from woman to woman and may include bloating, breast tenderness, weight gain, aggression, trouble concentrating, headache/backache, food cravings, fatigue, tearfulness, irritability, anxiety, and mood swings or depression. Up to 85% of menstruating women experience some of these symptoms. About 2-10% having severe symptoms. Treatment includes education, nutrition, exercise and medication.

VAGINA: The vagina is a 3-4 inch muscular tube extending from the cervix to the external genitalia. The back wall is longer that the front wall and can stretch four or five times its normal size during childbirth.

Functions of the vagina: (1). The female organ of intercourse (2). Passageway for the arriving male sperm (3). A canal through which the baby is born (4). A passageway for the menstrual flow.

HYMEN: also called “maidenhead”. It is a thin membrane that stretches across the opening of the vagina. It varies in thickness and extent, and is sometimes absent. In the center of the hymen is a circular perforation. It is through this perforation that the menstrual flow leaves the vagina and that the tampon or internal protection is inserted. In rare cases, there is no central perforation and the menstrual flow is blocked. Medical assistance is indicated in this situation.

• The absence of a hymen is not a sign that a girl is no longer a virgin, nor is the presence of the hymen an absolute sign of virginity. If the hymen is present it will usually rupture and tear at several points during the first coitus (intercourse) which can cause bleeding.

EXTERNAL FEMALE GENITALIA:

• Mona Pubis – fatty cushion over the front surface of the pubic bone. Is the female version of the scrotum.

• Labia Majora – large heavy folds of skin “large lips” that surrounding the vagina opening. It protects the external reproductive organs. They are compared to the scrotum in males. After puberty, the labia majora is covered with hair.

• Labia Minora – 2 small inner folds of skin “Small lips” between the Labia Majora and vagina. Have mucus and oil membranes and are hairless.

• Clitoris – a small sensitive protrusion that is comparable to the penis in males. The clitoris is covered with a fold of skin, called the prepuce, which is similar to the foreskin at the end of the penis. Like the penis, the clitoris is very sensitive to stimulation and can become erect.

• Greater and Lessor Vestibule (also called the Bartholin’s Glands). Produces mucus during arousal and intercourse.

MENOPAUSE: during menopause the female reproductive system gradually stops making the female hormones necessary for the reproductive cycle to work. When the body no longer produces these hormones a woman is considered to be menopausal and no longer has menstrual periods. It usually occurs between the ages of 47-59 years of age.

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