Chapter 4 - Genital Anatomy and Sexual Response Flashcards
Part 1
Sexual and reproductive anatomy consists of both ____ and ____
internal sex organs and external sex organs
external female genitals are known collectively as ____
the vulva
mons pubis
fatty pad of tissue covering the junction where the right and left pubic bone meet at the midline (pubic symphysis); covered in pubic hair
pubic hair
can be used for sexual signalling but can be used as a barrier for friction during intercourse, temperature changes; can be removed for aesthetics or other reasons
the clitoris
very sensitive organ important in female sexual response; consists of the tip (glans clitoris, only external part); shaft consisting of two corpora cavernose; two crura
labia majora
“outer lips” of vulva; covered with pubic hair to some degree and to personal preference; many nerve endings; important for sexual arousal; provide protection for sensitive clitoris, labia minora, and vagina
labia minora
“inner lips” of vulva; hairless folds of skin between the labia majora; important for sexual stimulation and arousal; vary widely in appearance
urethral opening (vulvar vestibule)
area of the vulva contained within the labia minora; has a lot of nerve endings within the vulvar vestibule; in general not highly sensitive; urethra is the tube that takes the urine from the bladder to be expelled from the body
vaginal opening (vulvar vestibule)
very sensitive region of the vulvar vestibule that varies in size; lies below urethral opening; may be covered or partially covered by the hymen; appearance can change throughout life (virginal, nulliparous, parous)
the hymen (vulvar vestibule)
thin membrane partially covering vaginal opening; typically some natural degree of separation to allow for menstrual flow; many types (normal, imperforate, microperforate, septate)
the vagina
canal that starts at vaginal opening and extends towards base of spine; connected to cervix at top; measures about 7.5-12.5cm; lengthens by 5-7.5cm when aroused
3 tissue layers of walls of vagina
vaginal mucosa, muscular layer, protective covering; extremely elastic to accommodate intercourse and child birth
the Bartholin glands
small pair of glands to left and right of vagina towards the bottom; contribute to small amounts of vaginal lubrication during sexual excitation esp just before orgasm
the Skene’s glands
pair of glands on front wall of vagina; ducts empty into urethra; may be equivalent of a “female prostate”; believed to contribute to sensitivity of the G-spot
G-spot (Grafenberg Spot)
highly sensitive area (depending on woman) on the front wall of the vagina; existence is debatable but accepted; some females excrete a fluid very similar to male prostate fluid from their urethras; prevalence of ejaculation varies from 10% to 54% based on self-reports
the cervix
lower third of uterus and located at the top of the vagina; secretes mucous; opening of cervix is called os; 1500 canadian women are diagnosed with cervical cancer
the uterus
upper two thirds of the uterus is called the fundus or body; consists of 3 layers: endometrium (innermost), myometrium (muscular), perimetrium (deepest)
ovaries
one ovary on each side of the uterus; endocrine glands that produce both estrogens and progestins; ovaries contain the ova (eggs, released at ovulation)
fallopian tubes
two fallopian tubes, one on each side; also called oviducts or uterine tubes; carry ova from ovaries to uterus; fertilization usually occurs in the infundibulum
female breasts
one of the first secondary sex characteristics to develop in females starting at around age 9/10; most important function is nourishing an offspring; breast/nipple area is well innervated and is sensitive to erotic stimulation as well; large variation in size and shape (and colour of areola)
____ cancer is the most common cancer affecting women
breast
the male external genitals consist of the ____ and the ____
penis; scrotum
functions of the penis
sexual pleasure, urination, reproduction
sections of the penis
root, shaft, glans
____ muscles make up the penis and also contain ____ and ____
smooth; 2 corpora cavernosa and 1 corpus spongiosum (with urethra)
what happens during an erection
purely a vascular phenomenon; smooth muscle relaxes causing arteries to dilate; veins are compressed
neurotransmitters involved in erections
nitric oxide to gain an erection; epinephrine and norepinephrine for loss
average penis size
9.2cm/3.2in flaccid; 13.1cm/5.1in erect
average angle of erection
10 degrees above horizontal when standing
what is circumcision
surgical procedure that removes foreskin; often done for religious reasons; about 30% of men are circumcised
what is the scrotum
loose pouch of skin that hangs under base of penis and contains testes; outer layer of skin with a little hair; inner layer of involuntary muscle called the dartos (makes muscle contract in cold)
internal sex organs of a male
testes (seminiferous tubes, epididymis, vas deferens); seminal vesicles; prostate gland; Cowper’s gland
the testes
reproductive and endocrine glands that produce sperm and secrete male sex hormones (androgens); spermatic cord suspends each testis in scrotum; surrounded by a layer of muscle called the cremaster muscle
development of testes
formed in fetus’s abdominal cavity; 3% are born with one undescended testis; pain from compression/strikes are felt deep in the abdomen where the testes are first developed
what is castration
removal or destruction of testicles; most current castrations are not done before puberty and are performed surgically or chemically to control disease such as prostate cancer
the seminiferous tubules
packed inside testes; produce and store sperm (spermatogenesis); interstitial cells located between the tubules produce androgens (testosterone)
the epididimys
covers part of each testicle; functions to mature and store sperm; made up of three sections (head, body, tail)
the vas deferens
carries sperm to the prostate gland, where they enter the urethra; part of the spermatic cord; sperm are transported through the vas deferens by cilia and muscle contractions
seminal vesicles
two tubular glands next to the prostate gland near the ends of the vas deferens; contributes a sugary alkaline fluid that makes up about 70% of ejaculate fluid
the prostate gland
lies directly below the bladder; secretes a thin, milky, alkaline fluid that makes up about 30% of the ejaculate fluid; prostate cancer is the most common malignancy in men
Cowper’s Glands
two pea sized structures that lie on each side of the urethra below the prostate; secrete pre-ejaculate that prepares the urethra for ejaculate upon arousal; this fluid can contain healthy and active sperm
semen and sperm
semen is made mostly from fluid from the seminal vesicles and prostate gland; each ejaculation contains about 1tsp of semen and 200-500 million sperm
path of sperm
seminiferous tubules > epididymis > vas deferens > ejaculatory duct (seminal vesicles and prostate) > outside
3 sexual response cycles
- Masters and Johnson’s 2. Kaplan’s three stage model 3. Basson’s model (female)
Masters and Johnson’s sexual response cycle
first researches to investigate sexual response cycles; focused on physiological aspects of sexual response; two fundamental processes of sexual response, myotonia (muscle tension) and vasocongestion (swelling/pooling of blood)
four phases (Masters and Johnson’s)
Excitement, Plateau, Orgasm, Resolution
excitement phase
vasocongestion; penile erection; vaginal lubrication
excitement phase (males)
dartos and cremaster muscles contract; increased pulse, breathing, BP; sex flush
excitement phase (females)
swelling of clitoral glans; clitoral crura and vestibular bulbs become engorged; cervix and uterus pulls up; increased pulse, breathing, BP; sex flush
plateau phase
responses from excitement peak and level off until orgasm; dramatic surge of sexual tension
orgasm phase
briefest phase; muscle spasm and ejaculation in males; vaginal and uterine contraction in females
orgasm phase (males)
- emission phase: vas deferens, seminal vesicles, and prostate contract forcing ejaculate into the bulb at the base of the urethra 2. expulsion phase: urethral bulb, muscles at the base of penis, and urethra contract rhythmically
orgasm phase (females)
uterus and lower third of vagina contract rhythmically; rectal pressure oscillates between 8 and 13 times a second
resolution phase
sexual system returns to its unaroused state
Kaplan’s three stage model
three phases: desire, excitement, orgasm; includes physiological processes in sexual response; adds cognitive component that is lacking in Masters and Johnson’s
Basson’s Model of Female Sexual Response
theory more or less agrees with Kaplan’s however desire doesn’t have to be the precursor for having intercourse or other sexual relations; Basson found that women may engage in sex for non-sexual reasons (ex. emotional closeness)
disabilities and sexual response
any and/or all aspects of the sexual response cycle can be affected in those with certain disabilities; cycle can be unaffected in some; having a disability doesn’t mean that “sex” is impossible
age-related decrease in sexual response
with increasing age, arousal takes longer; intensity of all aspects of one’s sexual response tends to become dampened
sex differences in sexual response
males experience a refractory period but females do not (can more readily experience multiple orgasms); orgasmic experiences differ
