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3. Female Sexual Anatomy. Female Sex Organs. All embryos appear as female at first Genetic and hormonal signals trigger the development of male organs in those embryos with XY chromosomes that will become male. Female Sex Organs in Utero. Female Sex Organs.
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3 Female Sexual Anatomy
Female Sex Organs • All embryos appear as female at first • Genetic and hormonal signals trigger the development of male organs in those embryos with XY chromosomes that will become male
Female Sex Organs • In spite of all that is known about female sex organs, some anatomical questions remain unknown or disputed • Range in clitoral size • Existence and function of the G-spot • Placement of nerves in the pelvic cavity
Female Sex Organs • Sex organs serve a reproductive function • Also serve other functions: • Bringing pleasure to self • Giving pleasure to others • May serve to attract potential sexual partners • Sharing of genital sexuality can play a bonding role in relationships
External Structures • External female genitals: • mons pubis • clitoris • labia majora • labia minora • These genitals are collectively known as the vulva • Often referred to as “vagina,” yet the vagina is an internal structure
Mons Pubis • Latin for “pubic mound:” • The pad of fatty tissue that covers the area of the pubic bone about 6” below navel. • Pubic hair grows on mons pubis beginning in puberty • In many women, this area is sensitive to stimulation
Clitoris • The Clitoris is the center of sexual arousal in the female • Contains a high concentration of nerve endings • Exquisitely sensitive to stimulation • glans clitoris: the shaft of the clitoris • Clitoral hood: covers glans when clitoris not engorged • Structurally analogous to penis, though sole function of the clitoris is sexual arousal
Clitoris • Clitoris also has an internal structure • Two 3.5” long branches called crura • crura contain two corpora cavernosa: hollow chambers that fill with blood and swell during arousal • The clitoris when stimulated • Enlarges initially, then retracts beneath hood just before and during orgasm • Follows same pattern with repeated orgasms, though swelling is less pronounced
Labia Majora and Minora • Labia Majora • Two folds of spongy flesh extending from the mons pubis and enclosing the labia minora, clitoris, urethral opening, and vaginal entrance
Labia Majora and Minora • Labia Minora • Small folds within the labia majora that meet above the clitoris to form the clitoral hood • They vary in appearance from woman to woman • They are sensitive to the touch and swell during sexual arousal • They enclose the “vestibule:” the vaginal opening
External genitals during sexual arousal • Clitoris becomes erect • Labia minora widen • Vestibule (vaginal opening) becomes visible • Bartholin’s glans (located in the vestibule) secrete small amount of moisture
Internal Structures • Vagina: from Latin word for sheath • Two reproductive functions: • Encompasses penis during coitus (vaginal intercourse) • Birth canal • Introitus: the lower third of the vagina • The majority of the vagina’s nerve endings are there • Hymen: named for Roman god of marriage • a thin membrane that partially covers introitus prior to first intercourse or other insertion
Internal Structures • Grafenberg Spot (G-spot) • An erotically sensitive area on front wall of the vagina mid-way between pubic bone and cervix • Existence somewhat controversial • Uterus: a hollow, thick-walled muscular organ • Accommodates developing fetus during pregnancy • Only 3” by 3” in women who have not given birth • Inner lining of uterine walls known as endometrium • Cervix: the tapered end of the uterus, extends and opens into the vagina • Secretes mucous; menstrual fluid travels through
Internal Structures • Ovaries:gonads that produce gametes • Produce egg cells (oocytes; ova) for reproduction • Two ovaries; size and shape of large almonds • Ovaries release oocytes in a process called ovulation • Fallopian tubes: • Also known as uterine tubes of oviducts • One tube extends toward each ovary • They fan over the ovaries, and carry oocytes into the uterus during ovulation
Other Structures • Urethra: tube through which urine passes • Urethral opening • Perineum: area between genitals and anus • Pelvic floor
Other Structures • Anus: opening of rectum • Contains two sphincters (circular muscles that open and close like valves) • Some women and men find that the tissue of the anus is erotically sensitive • The lining of the rectum is fragile • if engaging in anal sex play care must be taken not to rupture the delicate tissues
Other Structures • Breasts: both women and men have them • Reproductive function of female breasts is to nourish offspring through lactation • Composed of fatty tissue and 15-25 lobes that radiate around a central nipple • Areola: the ring of darkened skin around nipple • Nipples get erect in response to touch, cold, or sexual arousal • Many (not all) women find breast stimulation pleasurable.
Female Sexual Physiology: Reproductive Hormones • Hormones: chemical substances that serve as messengers • Gonadotropins act directly on gonads • Estrogens: affect maturation of reproductive organs, menstruation, and pregnancy • Progesterone: helps maintain the uterine lining
Female Sexual Physiology: The Ovarian Cycle • Cycle averages 28 days • Normal women’s cycles last between 21 & 40 days • Generally occurs in only one ovary per month
The Ovarian Cycle • 3 Phases: • Follicular phase: Days 1-10 • Hormones signal 10 to 20 follicles to grow on ovaries; Estrogen matures one oocyte • Ovulatory phase: Days 11-14 • Oocyte undergoes cell division; Follicle wall thins and ruptures; oocyte enters abdominal cavity near fimbrae of fallopian tube • Luteal phase: Days 14-28 • Estrogen levels drop; egg travels through fallopian tube towards uterus
The Menstrual Cycle • 3 Phases: • Menstrual phase (about 3-5 days) • Endometrium is shed • Endometrial tissue, mucous, other secretions, and 2-5 oz. Blood is expelled through vagina • Proliferative phase (about 9 days) • Endometrium thickens, clear thin mucus secreted • Ends with ovulation • Secretory phase (14 days) • endometrium prepares for arrival of fertilized ovum • If no fertilization, ends with shedding of endometrium
Menstrual Effects • Emotional, physical, or behavioral changes • The vast majority of women notice in the week prior to menstruation • More severe symptoms are associated with Pre- Menstrual Syndrome (PMS) • Dysmenorrhea • pelvic cramping and pain during menstruation • Caused by prostaglandins, a type of hormone • Amenorrhea • absence of menstruation for reasons other than aging
Female Sexual Response Models • Masters & Johnson 4 Phase Model: • excitement • plateau • orgasm • resolution
Female Sexual Response Models • Kaplan’s Tri-Phasic Model • Desire • Excitement • Orgasm
Female Sexual Response Models • Loulan’s Sexual Response Model: • Incorporates biological & affective dimensions • Willingness • Desire • Excitement • Engorgement • Orgasm • Pleasure
Desire: Mind or Matter? • Desire is the psychological component of sexual arousal. • A complex interaction between • Thoughts and feelings • Sensory organs • Neural responses • Hormonal reactions • Occurs throughout many parts of the body
Women’s Sexual Excitement • Sweating: moistening of vaginal walls • Tenting: inner 2/3 of vagina expands • Labia may enlarge or flatten & separate • Clitoris swells • Breathing and heart rate increase • Nipples become erect, breasts may enlarge • Uterus elevates
Women’s Sexual Excitement • As excitement increases • Clitoris retracts beneath clitoral hood • Vaginal opening decreases by about 1/3 • Outer third of vagina becomes more congested, forming the orgasmic platform. • Continued stimulation brings orgasm: • Rhythmic contractions of the vagina, uterus, and pelvic muscles accompanied by pleasurable sensation.