Human Reproductive Systems and Sexual Response

Vocabulary flashcards covering the male and female reproductive systems, internal and external genitalia, oogenesis and ovarian cycles, male sexual response phases, spermatozoa anatomy, semen composition, and hormonal feedback loops.

Vulva

The collective term for the female external genitalia, including the mons pubis, labia majora, labia minora, clitoris, and accessory glands.

Labium majus

One of two thick folds of skin and adipose tissue that enclose and protect the other external genital organs, featuring hair on its lateral surfaces and a hairless inner surface.

Labium minus

A thinner, hairless fold of skin situated just inside each labium majus.

Mons pubis

A mound of hair-covered adipose tissue that overlies the symphysis pubis.

Prepuce (female)

A hood of tissue formed over the clitoris by the meeting of the labia minora.

Clitoris

A small mound of erectile tissue resembling a penis whose function is strictly sensory, providing a source of sexual stimulation.

Lesser vestibular glands (Skene's glands)

A pair of mucous glands residing on either side of the urinary meatus that open into the vestibule to provide lubrication.

Vestibule

The area inside the labia minora that contains both the urethral and vaginal openings.

Greater vestibular glands (Bartholin's glands)

Two pea-sized glands located on either side of the vaginal opening whose ducts drain secretions to moisten the vulva and provide lubrication during intercourse.

Acini

Clusters of tiny, sac-like structures within breast lobules that secrete milk during lactation.

Lactiferous sinuses

Slight enlargements of the lactiferous ducts located just before they reach the nipple.

Areola

The pigmented area encircling the nipple, dotted with sebaceous glands that secrete sebum to lubricate and prevent dryness during nursing.

Suspensory ligaments (breast)

Ligaments that help support the breasts and attach them to the underlying pectoralis muscles.

Fallopian tubes

Muscular tubes about $4\,\text{inches}$ ($10\,\text{cm}$) long extending from the ovaries to the uterus.

Ampulla

The middle portion of the fallopian tube, which serves as the usual site of egg fertilization.

Infundibulum

The distal, funnel-shaped end of the fallopian tube.

Fimbriae

Finger-like projections at the distal end of the fallopian tube that fan over the ovary.

Uterus

A muscular chamber positioned between the urinary bladder and rectum that houses and nurtures a growing embryo.

Cervix

The inferior end of the uterus containing a canal that links the uterus to the vagina.

Vagina

A muscular tube about $3\,\text{inches}$ ($8\,\text{cm}$) long serving as a receptacle for penis and sperm, a discharge route for menstrual blood, and a birth canal.

Vaginal rugae

Ridges in the lower end of the vagina that stimulate the penis during intercourse and allow expansion during childbirth.

Hymen

A fold of mucous membrane that partially covers the entrance to the vagina.

Perimetrium

The outer layer of the uterine wall, composed of a serous membrane.

Myometrium

The thick middle layer of the uterine wall consisting of smooth muscle that contracts during labor to expel the fetus.

Endometrium

The innermost layer of the uterine wall where an embryo attaches, consisting of the stratum functionalis and stratum basalis.

Stratum functionalis

The upper two-thirds of the endometrium that thickens monthly to receive a fertilized egg and sloughs off during menstruation if fertilization does not occur.

Stratum basalis

The deep layer of the endometrium that attaches to the myometrium and regenerates the functionalis layer each month.

Ovaries

The primary female reproductive organs (gonads) that produce ova (egg cells) and sex hormones.

Graafian follicle

A fully matured, fluid-filled blister-like follicle on the surface of the ovary that bursts to release an egg during ovulation.

Ovulation

The process in which a mature graafian follicle bursts and releases an oocyte from the ovary.

Male Sexual Response Flowchart

The sequential four-phase flowchart outlining excitement, plateau, orgasm (emission and expulsion), and resolution in males.

Excitement phase (male sexual response)

Phase in which parasympathetic nerves cause penile arteries to relax and fill with blood, resulting in tissue engorgement and erection.

Plateau phase (male sexual response)

Phase in which the urethral sphincter contracts to prevent urine from mixing with semen, while heart rate, blood pressure, and respirations remain elevated.

Emission

The first stage of male ejaculation where the sympathetic nervous system stimulates peristalsis in the vas deferens and triggers fluid release from the prostate and seminal vesicles.

Expulsion

The second stage of male ejaculation where semen in the urethra activates somatic and sympathetic reflexes resulting in semen ejection.

Resolution phase (male sexual response)

Phase immediately following orgasm where sympathetic signals constrict penile arteries and erectile muscles contract to squeeze blood out, returning the penis to a flaccid state.

Spermatozoa Structure

Diagram showing the parts of a mature sperm: head (acrosome and nucleus), middle piece (mitochondria), and tail (flagellum).

Acrosome

A cap topping the head of the sperm containing enzymes that help the sperm penetrate the egg during fertilization.

Middle piece (sperm)

The section of a mature sperm containing numerous mitochondria that supply energy needed for migration up the female reproductive tract.

Semen

A fluid emitted during ejaculation containing sperm and accessory gland secretions, composed of about $65\%$ seminal vesicle fluid, $30\%$ prostate fluid, and $5\%$ bulbourethral fluid.

Testosterone negative feedback loop

Regulatory mechanism where high testosterone inhibits hypothalamic GnRH and pituitary LH secretion to decrease production, while low testosterone stimulates LH secretion to step up production.

Male Infertility Criteria

Condition indicated by a sperm count lower than $20\,\text{million}$ sperm per ejaculate or a total volume per ejaculate below $2\,\text{ml}$.