Reproductive System Glossary

Accessory glands – Glands that produce fluids contributing to semen, including seminal vesicles, prostate, and bulbourethral glands

Acrosome – Cap-like structure covering the headRounded proximal end that fits into the acetabulum of the hip bone. of a sperm cell containing enzymesProteins that speed up chemical reactions in the body. for penetrating the egg

Adolescence – Period of physical and psychological developmentThe process of growth and differentiation. from puberty to adulthood

Androgen binding protein – Protein produced by Sertoli cellsThe basic structural and functional units of life. that concentrates testosterone in the seminiferous tubules

Androgens – Male sex hormones, primarily testosterone

Andropause – Gradual decline in testosterone levels in aging males

Antrum – Fluid-filled cavity within a developing ovarian follicle

Arteries of penis – Blood vessels supplying the penis with oxygenated blood

Atresia – Degeneration of ovarian folliclesStructures in the ovaries that contain developing oocytes. that do not reach maturity

Autosomes – Non-sex chromosomes (chromosomes 1-22 in humans)

Basal layer – Bottom layer of the endometriumThe inner lining of the uterus that thickens during the menstrual cycle to support a potential pregn that remains during menstruation

Blood-testis barrier – Barrier formed by Sertoli cells that protects developing sperm from the immune system

Broad ligament – Wide fold of peritoneumThe membrane lining the abdominal cavity and organs. supporting the uterusThe muscular organ where a fertilized egg implants and develops., ovariesThe female gonads that produce eggs and hormones., and uterine tubesAlso called fallopian tubes, they transport the oocyte to the uterus.

Bulbourethral glands – Small glands that secrete pre-ejaculatory fluid to lubricate the urethraThe tube that carries urine from the bladder to the outside of the body.

Cervix – Lower, narrow portion of the uterus that opens into the vaginaThe muscular canal connecting the uterus to the external genitalia.

Clitoris – Erectile structure located at the anteriorThe front of the body or toward the front when standing in the anatomical position. junction of the labia minoraThe inner folds of skin surrounding the vaginal opening.

Corpora cavernosa – Paired columns of erectile tissue in the penis

Corona radiata – Layer of follicular cellsCells surrounding the oocyte that support its development. surrounding the ovulated oocyte

Corpus albicans – Scar tissue that forms after the corpus luteum degenerates

Corpus luteum – Temporary endocrine structure formed from a ruptured follicle that secretes progesteroneA hormone that supports pregnancy and regulates the menstrual cycle.

Corpus spongiosum – Column of erectile tissue surrounding the urethra in the penis

Counter-current heat exchange – Mechanism in the pampiniform plexus that cools arterial blood entering the testes

Cremaster muscle – Muscle that raises and lowers the testes to regulate temperature

Crossing over – Exchange of genetic material between homologous chromosomes during meiosis

Crura – Paired internal extensions of the clitorisA small, erectile structure in the female external genitalia that is sensitive to stimulation. or penis that attach to the pubic bones

Dartos fascia – Layer of smooth muscle and connective tissue in the scrotum

Dartos muscle – Smooth muscle in the scrotal wall that wrinkles the skinThe body’s largest organ, providing protection and regulation. to reduce heat loss

Descent of testes – Developmental process where testes move from the abdomen into the scrotum

Detumescence – Loss of erection as blood drains from erectile tissues

Dihydrotestosterone – Potent androgen converted from testosterone

Diploid – Having two complete sets of chromosomes (2n)

Ductus deferens – Muscular tube that transports sperm from the epididymis to the ejaculatory duct

Efferent ductules – Small tubules that transport sperm from the rete testis to the epididymis

Ejaculation – Expulsion of semen from the penis

Ejaculatory duct – Short duct formed by the union of the ductus deferens and seminal vesicle duct

Emission – Movement of semen into the urethra prior to ejaculation

Endometrium – Inner lining of the uterus that thickens and sheds during the menstrual cycleThe monthly cycle of changes in the female reproductive system.

Epididymis – Coiled tube on the testis where sperm mature and are stored

Erectile tissues – Vascular tissues that engorge with blood during sexual arousal

Erection – Enlargement and stiffening of the penis or clitoris due to blood engorgement

Estrogens – Female sex hormones produced primarily by the ovaries

Excitement – First phase of the sexual response cycle characterized by increased blood flow

Expulsion – Second phase of ejaculation where semen is forcefully expelled

External genitalia – External reproductive structures (penis and scrotum in males; vulvaThe external female genitalia. in females)

Fertilization – Union of sperm and egg to form a zygote

Fimbriae – Finger-like projections at the end of the uterine tubes that capture the ovulated oocyte

Flagellum – Whip-like tail of a sperm cell that provides motility

Follicle stimulating hormone – Pituitary hormone that stimulates follicle development and spermatogenesis

Follicles – Structures in the ovary containing developing oocytes

Follicular cells – Cells surrounding and nourishing the developing oocyte

Follicular fluid – Fluid within the antrum of a developing follicle

Follicular phase – Phase of the ovarian cycleThe cycle of follicle development, ovulation, and corpus luteum formation. when follicles develop

Frenulum – Fold of tissue on the underside of the penis connecting the glansThe exposed, sensitive tip of the clitoris. to the shaft

Functional layer – Upper layer of the endometrium that is shed during menstruation

Fundus – Upper rounded portion of the uterus

Gametes – Reproductive cells (sperm and eggs)

Gametogenesis – Process of producing gametes

Germinal epithelium – Layer of cells in the seminiferous tubules that gives rise to sperm

Glans – Enlarged tip of the clitoris or penis

Glans penis – Enlarged distal end of the penis

GnRH – Gonadotropin-releasing hormone produced by the hypothalamusA small but vital brain region controlling hormones, temperature, and autonomic functions.

Gonadotropin-releasing hormone – Hypothalamic hormone that stimulates release of FSH and LH

Gonads – Primary reproductive organs (testes in males, ovaries in females)

Graafian follicle – Mature ovarian follicle ready for ovulationThe release of a mature oocyte from the ovary.

Granulosa cells – Follicular cells that secrete estrogen and support oocyte development

Haploid – Having one complete set of chromosomes (n)

Hymen – Thin membrane partially covering the vaginal opening

Hypothalamic-pituitary-gonadal axisSecond cervical vertebra; has the odontoid process (dens) for pivoting head (“no” motion). – Hormonal system regulating reproductive function

Hypothalamic-pituitary-ovarian axis – Hormonal feedback loop regulating the ovarian cycle

Infundibulum – Funnel-shaped opening of the uterine tube near the ovary

Inhibin – Hormone that inhibits FSH secretionThe process of moving substances from the blood into the nephron tubule to be excreted in urine.

Internal genitalia – Internal reproductive structures

Interstitial cells – Testosterone-producing cells in the testes (Leydig cells)

Isthmus – Narrow portion of the uterine tube or uterus

Labia majora – Outer folds of skin and adipose tissue surrounding the vulva

Labia minora – Inner folds of skin flanking the vestibuleThe area between the labia minora.

Leptin – Hormone that signals adequate energyThe capacity to do work or cause change. stores for reproductionThe process of producing offspring.

Luteal phase – Phase of the ovarian cycle after ovulation when the corpus luteum is active

Lutein cells – Cells of the corpus luteum that secrete progesterone

Luteinizing hormone – Pituitary hormone that triggers ovulation and stimulates testosterone production

Male climacteric – Period of declining reproductive function in aging males

Meiosis – Cell division process that produces haploid gametes from diploidA cell with two sets of chromosomes, one from each parent (2n). cells

Membranous urethra – Short segment of the male urethra passing through the urogenital diaphragm

Menarche – First menstrual period

Menopause – Cessation of menstrual cycles marking the end of reproductive years

Menstrual cycle – Monthly cycle of changes in the female reproductive systemThe organ system responsible for producing gametes and offspring.

Menstrual phase – Phase when the functional layerThe superficial layer of the endometrium that is shed during menstruation. of the endometrium is shed

Mesovarium – Part of the broad ligament supporting the ovary

Mons pubisAnterior portion of the hip bone; meets its pair at the pubic symphysis. – Rounded fatty pad overlying the pubic symphysisCartilaginous joint connecting the two pubic bones at the midline.

Myometrium – Smooth muscle layer of the uterus

Myotonia – Muscle tension that increases during sexual arousal

Nurse cells – Sertoli cells that nourish and support developing sperm

Oogenesis – Process of egg cell development

Oogonium – Diploid germ cell that gives rise to primary oocytesImmature egg cells halted in development until puberty.

Orgasm – Peak of sexual pleasure characterized by rhythmic contractions

Ovarian artery – Artery supplying blood to the ovary

Ovarian cycle – Monthly cycle of follicle development, ovulation, and corpus luteum formation

Ovarian ligament – Ligament anchoring the ovary to the uterus

Ovaries – Female gonads that produce oocytes and sex hormones

Ovulation – Release of a secondary oocyteThe egg cell released during ovulation. from the ovary

Ovum – Mature egg cell

Pampiniform plexus – Network of veinsBlood vessels that return deoxygenated blood to the heart (except pulmonary veins, which carry oxyge surrounding the testicular artery that helps regulate testicular temperature

Paraurethral glands – Small glands opening near the urethral opening (Skene’s glands)

Penis – Male external genital organ for copulation and urination

Perimetrium – Outer serous layer of the uterus

Perineum – Region between the genitals and anusThe terminal opening of the digestive tract through which feces are expelled.

Phases of meiosis – Sequential stages of meiotic division (prophaseThe first stage of mitosis where chromatin condenses into visible chromosomes. I, metaphaseA stage of mitosis where chromosomes align at the metaphase plate. I, anaphaseA stage in mitosis or meiosis where sister chromatids or homologous chromosomes separate. I, telophaseThe final stage of mitosis where nuclear envelopes reform around separated chromosomes. I, prophase II, metaphase II, anaphase II, telophase II)

Placenta – Temporary organ providing nutrient and gas exchange between mother and fetus

Plateau – Second phase of the sexual response cycle with sustained high arousal

Polar body – Small, nonfunctional cell produced during oogenesisThe process of egg cell formation.

Premenstrual phase – Days before menstruation when progesterone levels decline

Prepuce – Fold of skin covering the glans of the penis (foreskin) or clitoris

Primary follicle – Ovarian follicle with a single layer of cuboidal follicular cells

Primary oocytes – Diploid cells arrested in prophase I of meiosis

Primary sex organs – Gonads (testes and ovaries)

Primary spermatocyte – Diploid cell that undergoes meiosis I to form secondary spermatocytes

Primordial follicles – Dormant follicles consisting of a primary oocyte surrounded by a single layer of flat cells

Primordial germ cells – Earliest recognizable cells in the germ cell lineage

Progesterone – Hormone produced by the corpus luteum that maintains the endometrium

Proliferative phase – Phase of the uterine cycle when the endometrium thickens

Prostaglandins – Lipid compounds in semen that stimulate smooth muscle contractions

Prostate – Gland surrounding the urethra that contributes fluid to semen

Prostate-specific antigen – Enzyme in prostatic fluid that liquefies semen

Prostatic urethra – Portion of the male urethra passing through the prostate gland

Puberty – Period of sexual maturation when reproductive capability is attained

Pudendum – External female genitalia (vulva)

Raphe of scrotum – External ridge on the scrotum marking the fusion line

Resolution – Final phase of the sexual response cycle when the body returns to the unaroused state

Rete testis – Network of tubules in the testis where seminiferous tubules converge

Round ligament – Ligament extending from the uterus through the inguinal canal

Scrotum – External sac containing the testes

Secondary follicle – Ovarian follicle with multiple layers of follicular cells and an antrum beginning to form

Secondary oocyte – Haploid cell released at ovulation that is arrested in metaphase II

Secondary sex characteristics – Physical features that distinguish males and females but are not directly involved in reproduction

Secondary spermatocyte – Haploid cell produced by meiosis I that undergoes meiosis II

Secretory phase – Phase of the uterine cycle when endometrial glands secrete nutrients

Semen – Mixture of sperm and seminal fluid

Seminal fluid – Fluid component of semen produced by accessory glands

Seminal vesicles – Glands that produce fructose-rich fluid comprising most of semen volume

Seminiferous tubules – Coiled tubules in the testes where spermatogenesis occurs

Sex chromosomes – X and Y chromosomes that determine biological sex

Sexual intercourse – Sexual contact involving penetration

Shaft of penis – Cylindrical body of the penis

Spermatic cord – Bundle of structures (ductus deferens, blood vessels, nerves) passing through the inguinal canal

Spermatids – Haploid cells produced by meiosis II that differentiate into sperm

Spermatogenesis – Process of sperm cell development

Spermatogonia – Diploid stem cells that give rise to primary spermatocytes

Spermatozoon – Mature sperm cell

Spermiogenesis – Process of spermatid differentiation into mature sperm

Spiral arteriesBlood vessels that carry oxygenated blood away from the heart (except pulmonary arteries, which carr – Coiled arteries in the endometrium that respond to hormonal changes

Spongy urethra – Longest portion of the male urethra passing through the corpus spongiosum

Suspensory ligament – Ligament attaching the ovary to the pelvic wall

Tenting effect – Expansion of the upper vagina during sexual arousal

Tertiary follicle – Mature ovarian follicle with a large antrum

Testes – Male gonads that produce sperm and testosterone

Testicular artery – Artery supplying blood to the testis

Testicular nerves – Nerves innervating the testes

Testicular vein – Vein draining blood from the testis

Testosterone – Primary male sex hormone

Theca – Outer layer of cells surrounding an ovarian follicle

Transudate – Fluid that passes through vaginal walls during sexual arousal for lubrication

Tunica albuginea – Fibrous capsule surrounding the testis or ovary

Uterine tubes – Tubes that transport oocytes from the ovary to the uterus (fallopian tubes)

Uterus – Hollow muscular organ where fetal development occurs

Vagina – Muscular tube extending from the cervix to the external genitalia

Vaginal rugaeFolds in the stomach lining that allow expansion when food enters. – Folds in the vaginal lining that allow for expansion

Vasocongestion – Engorgement of blood vessels during sexual arousal

Vein of penis – Veins draining blood from the penis

Vestibular bulbs – Erectile tissue on either side of the vaginal opening

Vestibule – Space enclosed by the labia minora containing urethral and vaginal openings

Vulva – External female genitalia

Zona pellucida – Glycoprotein layer surrounding the oocyte

Zygote – Diploid cell formed by fertilization of an egg by a sperm