EXAM 2 Human Sexual Development

Latin: “tail”: Organ for both sexual intercourse and urination.

• Average length 2.5-4 in. (flacid) and 6- even 13 in. erect.

Latin: “tail”: Organ for both sexual intercourse and urination.

• Average length 2.5-4 in. (flacid) and 6- even 13 in. erect.

Penis

Base of penis, anchored to pelvic bones by crura.

Root

Body of the penis.

Shaft

“crown”: Sensitive ridge between glans and shaft.

Corona

Extremely sensitive tissue on underside of penis connects glans and shaft.

Frenulum

Heavily innervated tip of penis.

Glans

Passage for semen and urine.

• Meatus: Urethral opening

Urethra

Two columns of spongy erectile tissue along the top of the penis.

Corpora cavernosa

Spongy tissue surrounding the urethra running underneath the penis.

Corpus spongiosum

Nerve fibers swell the arteries of the penis, allowing blood to rush into the corpora cavernosa and corpus spongiosum.

• Is a reflex that can occur without tactile stimulation, as in spinal injuries or during sleep.

Errection

Layer of skin that forms a sheath over the shaft and glans.

(Foreskin)

Prepuce

Cutting and removal of the prepuce.

Circumcision

Glands under the foreskin- produce smegma.

Tyson’s glands

Pouch of loose skin that holds testes.

Scrotum

Raises and lowers testes in response to temperature changes and arousal- maintains optimal spermatogenesis.

Cremaster muscle

Manufacture sperm and steroid hormones.

Testes

Produce testosterone.

Leydig cells

Sperm-producing tubes winding through the testes.

Seminiferous tubules

Sperm production.

Spermatogenesis

Develops in the cells lining the outer wall of the seminiferous tubules and move toward the center

Spermatogonium

• During the 8th and 9th month the testicles descend into the scrotum through the inguinal canal.

• occurs if the testicles do not descend.

• Due to higher temperature of the abdomen, sperm production cannot take place, and the infertility results if testes are not moved during childhood.

• Testicles that remain in the abdomen are at an increased risk of developing cancer.

• in infants can be treated with surgery.

Cryptorchidism

• Twisting of a testicle’s spermatic cord- typically results from abnormal development of the spermatic cord or membrane covering the testicle.

• Most common from puberty to age 25, but can happen at any age after exercise, intercourse, or sleeping.

Testicular Torsion

• Severe pain and swelling, abdominal pain, tenderness and aching may also occur.

• A physician must diagnose and untwist the cord with 24 hours to prevent the loss of the testicle.

Symptoms of Cryptorchidism

• Painful and persistent erection that is not associated with sexual desire/excitement.

• Due to blood becoming trapped in the penis erectile tissue.

• Drug use (cocaine, marijuana, or anticoagulants) is most common cause, although in many cases the cause is unknown.

• Erectile dysfunction drugs taken recreationally.

Priapism

• Draining blood from the penis w a syringe.

• Surgery may be necessary in some cases.

• Sexual functioning may be affected if effective treatment does not occur.

Treatment for Priapism

• Abnormal calcifications in the penis which may cause painful curvature which may make intercourse difficult or impossible.

• Crystal deposits in the connective tissue, trauma, high calcium levels, or calcification may contribute to the disease.

Peyronie’s Disease

• It typically lasts 2 years and may disappear suddenly

• Can be treated with medication or surgery

Treatment for Peyronie’s Disease

• Causes a scrotal mass (or a cyst) due to excessive fluid accumulation within tissue surrounding testicle.

• It may be due to the overproduction of fluid or poor reabsorption of fluid and may lead to pain and swelling.

Hydrocele

Removing the fluid

Treatment for Hydrocele

• A dime size area in the lower third of the front part of the vagina.

• Stimulation of this leads to pleasant sensation and arousal for some women and can result in orgasms possibly accompanied by the forceful expulsion of fluid, leading to the term “female ejaculation”

Grafenberg Spot (G-spot) and Female Ejaculation

• Lasts from 3-5 years and begins around 8yrs, but varies with race and weight (critical fat hypothesis). With puberty, the pituitary gland begins to secrete the hormones FSH and LH which stimulate the ovaries to produce estrogen.

• Estrogen leads to the development of various characteristics such as breast and pubic hair growth.

Female Puberty

• Around the age of 11 or 12 girls begin to ovulate, and some women feel a slight pain or sensation

Mittelschmerz

• lasts about 28 days, when the uterine lining builds up to prepare for a possible pregnancy.

The menstrual cycle

Four (Five) Phases of the Menstrual Cycle

• Menstruation

• Preovulatory phase

• Ovulatory phase

• Premenstrual/Luteal phase

• Menstrual phase

• days 1-6, 7.

• (Latin mensis: “month”): the shedding of the endometrium and unfertilized ova.

Menstruation

• days 7-13.

• The hypothalamus releases gonadotropin-releasing hormone to the ovaries to release follicle-stimulating hormone (FSH) which stimulates egg maturation and estrogen production.

Proliferative/Follicular/Preovulatory Phase

• days 14-17.

• Estrogen binds to receptors in the hypothalamus which over time stops the production of FSH and begins the production of luteinizing hormone (LH) which causes the mature ovum to burst out of its follicle (ovulation).

Ovulatory phase

changes- becomes more alkaline and more liquidized, which assists in sperm transport.

Cervical Mucus

• Ovulation does not occur in every menstrual cycle.

• Occur once or twice a year in women 20-30 years old and are more common in women who have just begun to menstruate or are nearing menopause.

Anovulatory cycles

• days 18-28.

• After releasing the egg, the follicle turns into a corpus luteum, which then manufactures progesterone and estrogen in case of pregnancy.

• If pregnancy occurs: the placenta develops and levels of progesterone and estrogen increase.

• If not: Progesterone and estrogen levels are maintained until ovum goes unfertilized, then plunge with the degeneration of the corpus luteum.

Premenstrual/Luteal phase

• low levels of progesterone and estrogen lead to endometrial shedding.

• This is about 2 ounces (4 tablespoons). The decline in estrogen causes an increase of FSH and the whole cycle begins again.

Menstrual phase

When the endometrium grows in places other than the uterus- ovaries, fallopian tubes, rectum, bladder, vagina, vulva, etc.

Endometriosis

• painful periods that last unusually long times are the most common.

• This can lead to sterility if untreated. Surgery may be necessary.

Symptoms of Endometriosis

• caused by staphylococcus bacterial growth in the vagina.

• Linked to tampon use.

Toxic Shock Syndrome (TSS)

• high fever, vomiting, and diarrhea.

• 10% death rate.

• Tampons should be changed often and used for shorter periods.

Symptoms of Toxic Shock Syndrome (TSS)

• Window when eggs are being matured

  • LH triggers the egg to come down (ovulation)

Days 7-13

Estrogen

Hormone that triggers the shut down of FSH

• idea that there are only 2 genders (M/F).

• The concept of a binary is based on statistical normality- the majority of a species- but not the entirety of a species.

Gender binary

• culturally defined behaviors seen as appropriate for males and females

Gender roles

biologically determined gender-specific behaviors

Gender traits

• one’s private sense of gender (e.g., M/F).

Gender Identity

• Sandra Bem (1981; 1983; 1987)

• organize our thinking about gender as determined by culture.

• becomes so ingrained that people do not even realize they are created by stereotypes.

Gender Schema Theory: Our Cultural Maps

• people who identify or express themselves within the gender roles of the society, or “sex & gender match”.

Cisgender

• people who identify or express themselves outside or separately from their biological sex- supposed to be generally applied to individuals whose appearance and behaviors do not conform to gender roles in that society.

Transgender

• Gender identity is inconsistent with his/her biological sex: can create gender dysphoria/ Gender Identity disorder.

• Onset of trans identity when gender identity develops in early childhood.

• This has existed for centuries and some socities consider this a third gender.

Transsexuals

• the gender or genders that a person is attracted to emotionally, physically, sexually, and romantically.

• not defined solely by sexual behavior

• does not imply gender identity

Sexual orientation

• 7-point scale ranging from exclusively heterosexual behavior (0) to exclusively homosexual behavior (6).

• First to suggest that people engaged in complex sexual behaviors and not just “homosexual” and “heterosexual”.

• Males: 2-4% to over 10%

• Females: 1-3%. Bisexuals: 3%.

• Percentages remain constant regardless of cultural acceptance. However, methods of measurement change

The Kinsey Continuum

• homosexuality,

• men,

• a single biological basis,

  • and confuses ___________ and gender

Research on orientation has historically focused on:

• Males: Orientation may be genetically linked (twins).

  • Hamer found homosexual males had more homosexual relatives on the mother’s side, and ‘identified a “gay” gene’ (no).

Genetics

• Males: homosexual men had lower levels of androgens than heterosexuals during sexual brain differentiation.

• Others found higher levels of androgens (digit ratio studies). Some have not found a relationship.

Hormones, Prenatal Factors

• Blanchard and Bogaert: Males: Fraternal ___ ___ contributes to a homosexual orientation: placental cells in the uterus influence later pregnancies-

• children born later could develop an immune response that influences gene expression.

Birth Order

• LeVay, 1991. Males: differences in the hypothalamus between gay men and heterosexual men.

Physiology

• 493,001 participants from US, UK, and Sweden. Examined entire genome- 5 autosomal genes were associated with same-sex behavior.

• All tested genetic variants accounted for 8 to 25% of the variation in same-sex sexual behavior.

• Genetic effects that differentiate heterosexual from same-sex sexual behavior are not the same as those that differ among nonheterosexuals in terms of number of partners, which suggests that there is no single continuum from opposite-sex to same-sex preference.

Ganna, et al, 2019

Asian Countries

• Buddhism does not condemn homosexuality so Buddhist countries generally accept it.

Latin American Countries

• A man is not considered a homosexual if he takes the active, insertive role. Sexual orientation is conflated with gender roles

• Believed that mother’s milk must be replaced with man’s milk (semen) for a boy to reach puberty.

• At 7yrs, boys begin oral sex with older men to ingest semen

• After puberty, the boy switches to the receiving role until 19, when he engages in primarily heterosexual relations.

  • What is considered homosexual behavior in other cultures is not ‘homosexual’ here.

Sambia (Papa New Guinea)

• Lesbianism was rarely explicitly illegal in most ancient societies

• Homosexuality was not treated with concern/interest by either early Jews or Christians.

• Homosexual activity was common- homosexual prostitution was taxed by the state.

The Ancient World

• Homosexual relations were not forbidden despite many sexual codes based on Church teachings.

• But by 1300, homosexuality was punishable by death in Europe, influencing the Western view of homosexuality for 700 yrs.

The Middle Ages

• Homosexuals were imprisoned and murdered

  • Western, predominantly Christian, societies have often existed without hostility to homosexuality

Nazi Germany

• Arousal and orgasm is physiologically no different.

• Gay and Lesbian couples were less “goal oriented” than heterosexual couples.

Masters & Johnson (1979)

Gay/lesbian couples have dominant and submissive partners.

Myth about Gay and Lesbian Sexual Response

Relationships are actually characterized by greater role flexibility and partner equality and lower levels of jealousy.

Truth about Gay and Lesbian Sexual Response

the Vulva

External Female Sex Organ

• fatty tissue cushioning pubic bone, covered in pubic hair

Mons veneris/pubis

• only known organ that functions solely for sexual pleasure.

• Varies in size.

• It is richly supplied with blood vessels and a higher concentration of nerve fibers than anywhere else on the body.

Clitoris

• erectile tissue (corpora cavernosa) that fills with blood during arousal.

Clitoral Shaft

• hood covering clitoris.

Prepuce

• smooth round tip of clitoral shaft. 8.000 nerve endings.

Glans

In some cultures, the clitoris and possibly other sexual organs are removed during circumcision.

Clitorectomy or infibulation

• outer, larger folds of skin that shield the labia minora

Labia majora

• inner folds that are thinner and hairless.

• Cover the urethral and vaginal openings.

• Differ considerably in appearance in different women.

• They contain oil glands and join at the clitoris to form the prepuce or "hood" of the clitoris.

Labia Minora

• region between the labia minora,

• containing the opening of the urethra and the vagina and the ducts of the Bartholin's glands

Vestibule

• vaginal opening, just below urethral opening.

Introitus

• fold of tissue across the vaginal opening, usually present at birth and usually removed during Ist coitus.

• The hymen can take many forms and vary by individual.

Hymen

Why is the hymen not proof of virginity

• because:

• May be born without one.

• Can be torn during exercise.

• May be flexible enough to withstand coitus.

• highly sensitive skin between the vaginal opening and the anus.

Perineum

• wing-shaped structures, containing corpora cavernosa, which attach clitoris to pubic bone

Crura/Crus

• cavernous structures that line the sides of the introitus and swell with blood during arousal

Vestibular bulbs

• 3-5 inch-long muscular canal connecting the uterus to the introitus- extremely elastic.

Vagina

• The cells of this layer- the vaginal epithelium- change structure across the menstrual cycle.

• Middle wall is muscular.

• Deepest layer is fibrous and connects vagina to pelvis.

• The first third of the vagina has numerous nerve endings, while the inner two-thirds have none or very few for most women.

Vaginal mucosa-inner layer of the 3 layers of the vaginal wall.

• entrance at lower end of the uterus

Cervix

• the opening of the cervix- the diameter of a straw.

Os

• womb, where fertilized ova implant and develop. Roughly the size of a fist (varies with cycle, births).

Uterus

• inner lining of the 3 layers of the uterus- connected to glands and blood supply-removed from body during menstruation, growth is triggered by hormones.

Endometrium

• highly muscular middle layer

Myometrium

• outer layer

Permetrium

• upper end of the uterus.

Fundus

• passages for ova from the ovaries to the uterus- lined with cilia for transport of the egg. Very thin.

Fallopian Tubes

• open-ended fingerlike projections which ova enter

Flimbriae

• produce ova and the sex hormones- testosterone, estrogen & progesterone.

• Testosterone is quickly converted to estrogen. Follicle stimulation hormone (FSH) and luteinizing hormone (LI) are released by the pituitary gland during each menstrual cycle, causing about 20 follicles in one ovary to begin maturing, but typically only one follicle bursts, releasing an ovum.

Ovaries