SEXUAL ANATOMY o Female-Internal FEMALE INTERNAL SEX ORGANS The internal sexual organs of the human female: Ovaries Fallopian Tubes Uterus Vagina OVARIES Defined: Produce ova and sex hormones. Each female has two ovaries about the size of an almond. Located at the ends of the fallopian tubes on each side of the uterus. OVARIES Perform two major functions: Produces mature ova (egg cells). Production of the female sex hormones. Estrogen: Responsible for female sex characteristics. Progesterone: Prepares the uterus for pregnancy. Human Chorionic Gonadotropin: Inhibits immune response towards embryo. At birth a female infant’s ovaries contain about 400,000 immature ova which is all the eggs she will ever have. Only about four to five hundred eggs will be released. OVARIES Ovarian follicles: Small sacs containing ova. Ovulation: Discharge of a mature ovum from the ovary. Fertile: Time when pregnancy may occur (3-4 days). If the egg is not fertilized during this time, it is expelled during menstruation. FALLOPIAN TUBES Ducts that connect the ovaries to the uterus. Each fallopian tube fans out into fingerlike extensions called fimbriae. Fimbriae: Capture the egg and deliver it into the tube. If sperm are present, the egg may be fertilized while in the upper portion of the fallopian tube. If the fertilized egg does not proceed all the way to the uterus, tubal pregnancy may result. UTERUS Where the fertilized egg develops until birth. The uterus (womb) is a hollow, muscular organ shaped like an upside-down pear. The uterus is suspended in the pelvic cavity by a number of flexible ligaments. Prior to giving birth: 3 inches long, 3 inches wide One inch thick near the top Weighs about 2 ounces UTERUS No organ undergoes the same kind of dramatic change in adulthood as the uterus: It grows to 2 pounds by the end of pregnancy. After pregnancy it shrinks back almost to its original size. _________________________________________________________ The uterus is divided into three major parts: Fundus: Uppermost part. Uterine Body: Central region of the uterus. Cervix: Small, lower end of the uterus that protrudes into the vagina. Os: Opening in the middle of the cervix that leads to the interior of the uterus. UTERUS Uterine wall is composed of three layers: Endometrium: Tissue that lines the inside of the uterine walls. Expelled during menstruation. Myometrium: Smooth muscle layer of the uterine. Source of the contractions necessary for childbirth. Perimetrium: Thin membrane covering the outside of the uterus. VAGINA The stretchable canal that extends from the external genital opening to the cervix. Three major functions: Receptacle for the penis. Passageway for menstrual flow. Birth canal. Vagina is a 3-5 inch long passageway. At rest the walls of the vagina lie against one another. During sexual arousal, the cervix lifts upward and the vagina expands in length to receive the penis. VAGINA Consists of three layers: Vaginal Mucosa: Mucous membrane. Its cells are the source of vaginal lubrication for intercourse. Muscularis: Middle layer of the vaginal walls. Muscles that contract during orgasm. Fibrous Layer: Connects the vagina to other pelvic structures.