Uterine tube (Fallopian tube/Oviduct) (YOO-tuh-ryn toob): A muscular, simple ciliated columnar epithelial-lined tube that extends from the uterus toward the ovary; its primary function is to capture the oocyte after ovulation and provide the site where fertilization and early embryonic development typically occurs. It consists of a highly ciliated infundibulum with finger-like fimbriae (closest to the ovary), a wider ampulla (with a highly folded mucosa), a narrower isthmus (with thick muscular wall) and an intramural portion that pass through the wall of the uterus.
Ovary (OH-vuh-ree): The female gonad, an endocrine and reproductive organ responsible for producing the oocyte and secreting steroid hormones (estrogen and progesterone); it consists of an outer layer (cortex) that contains developing follicles, and inner medulla of dense connective tissue, nerves, blood vessels and lymphatics. The ovaries are attached to the lateral sides of the uterus via the ovarian ligaments – which contain the ovarian blood vessels.
Round ligament of the uterus (rownd LIG-uh-munt uv thuh YOO-tuh-rus): A band of fibrous connective tissue extending from the uterus, through the inguinal canal, and attaching to the labia majora; it helps maintain the anteflexed position of the uterus. During development, this develops from the gubernaculum.
Pubic symphysis (PYOO-bik SIM-fuh-sis): A midline joint located anteriorly between the left and right pubic bones; it is a symphysis (a type of cartilaginous joint) where the bones are connected by a pad of fibrocartilage.
Clitoris (KLIT-uh-ris): A highly sensitive, erectile organ of the female external genitalia/vulva; it is composed of two corpora cavernosa and a glans, rich in sensory nerve endings, and covered by a clitoral prepuce.
Labia minora (LAY-bee-uh mih-NOR-uh): Two thin, hairless folds of skin located medially to the labia majora; they contain numerous blood vessels, elastic fibers, and sebaceous glands, and form the lateral boundaries of the vestibule.
Labia majora (LAY-bee-uh muh-JOR-uh): Two prominent, longitudinal folds of skin that form the lateral boundaries of the pudendum; composed of fat, smooth muscle, and dense connective tissue, they are covered in pubic hair after puberty.
Muscular pelvic diaphragm (MUS-kyoo-ler PEL-vik DY-uh-fram): A sheet of striated muscle (primarily the levator ani and coccygeus muscles) that forms the floor of the pelvis; it provides support for the pelvic viscera and contributes to sphincter control.
Coccyx (KOK-siks): The small, terminal bone of the vertebral column (the tailbone); it is typically formed by the fusion of three to five small vertebrae and serves as an attachment point for parts of the pelvic diaphragm.
Dorsal artery (of the clitoris) (DOR-sul AR-tuh-ree): A terminal branch of the internal pudendal artery that runs along the dorsal surface of the clitoris; it supplies oxygenated blood mainly to the glans and the corpus cavernosum fascia.
Dorsal vein (of the clitoris) (DOR-sul vayne): A vein that drains blood from the dorsal surface of the clitoris; it primarily empties into the vesical venous plexus.
Deep artery (of the clitoris) (deep AR-tuh-ree): An artery that travels through the center of the corpus cavernosa (clitoris); during sexual arousal, it dilates to fill the erectile tissue with blood, causing erection.
Corpus cavernosa (clitoris) (KOR-pus kav-er-NOH-suh): Two cylindrical masses of erectile tissue that make up the body of the clitoris; they contain many interconnected vascular spaces (cavernae) that fill with blood during arousal.
Clitoral fascia (KLIT-uh-rul FASH-uh): A tough, deep layer of fibrous connective tissue that surrounds the entire body of the clitoris, deep to the skin; it helps to contain the erectile tissue during erection.
Tunica albuginea (of the clitoris) (TOO-nih-kuh al-byoo-JIN-ee-uh): A dense, white layer of irregular connective tissue that immediately encapsulates each corpus cavernosa and the corpus spongiosum of the clitoris; its strength helps maintain the rigidity of the erection.
Primordial follicle (pry-MOR-dee-ul FOL-ih-kul): The earliest and most abundant stage of an ovarian follicle, found in the ovarian cortex; it consists of a single oocyte arrested in Prophase I of meiosis, surrounded by a single layer of flattened follicular cells (precursors to granulosa cells). These are the stores of non-growing follicles in the ovaries. At birth, around 2 million primordial follicles exist in the ovaries; by puberty, around 400k primordial follicles exist in the ovaries.
Granulosa cell (gran-yuh-LOH-suh sell): Epithelial cells that surround the developing oocyte in the ovarian follicle; they proliferate, produce estrogen, and convert androgens provided by the theca interna into estrogen. They produce the liquor folliculi (follicular fluid) that creates the follicular antrum.
Oocyte (OH-uh-syt): The female germ cell (egg) produced in the ovary; it is a large cell that undergoes meiosis to become a mature ovum, ready for fertilization. Primary oocytes develop from an oogonium prior to birth when all oogonia enter, and become arrested at, Prophase of meiosis I. After puberty, a LH surge results in one primary oocyte per month to complete meiosis I to become a secondary oocyte arrested at Metaphase II of meiosis. Secondary oocytes, arrested at Metaphase II, are ovulated and do not complete meiosis unless fertilization takes place.
Zona pellucida (ZOH-nuh puh-LOO-sih-duh): A thick, acellular layer composed of glycoproteins that immediately surrounds the space (perivitelline space) adjacent to the plasma membrane of the oocyte in developing follicles; it is essential for species-specific sperm recognition and blocks polyspermy. It is secreted by the oocyte and develops during the primary follicle stage (from unilaminar to multilaminar).
Primary follicle (PRY-mer-ee FOL-ih-kul): An pre-antral ovarian follicle that has progressed from the primordial stage; it is characterized by a growing oocyte surrounded by one (unilaminar) or more (multilaminar) layers of cuboidal granulosa cells. It contains a primary oocyte arrested at Prophase 1. As the primary follicle and oocyte grows, a zona pellucida develops between the oocyte’s cell membrane (oolemma) and the granulosa cells.
Secondary (antral) follicle (SEK-un-der-ee AN-trul FOL-ih-kul): An ovarian follicle characterized by the appearance of a fluid-filled cavity, the antrum, among the layers of granulosa cells; it is the stage that is cyclically recruited by FSH to continue to grow to become a preovulatory (Graafian) follicle. It contains a primary oocyte arrested at Prophase I, with a zona pellucida.
Antrum (AN-trum): A crescent-shaped, fluid-filled space that appears within the secondary (antral) follicle as the granulosa cells secrete liquor folliculi (follicular fluid); it enlarges dramatically as the follicle matures.
Theca interna (THEE-kuh in-TUR-nuh): The vascularized, inner layer of specialized stromal cells that develops outside the basement membrane of the growing follicle; these cells possess receptors for LH and secrete androgen hormones (which the granulosa cells convert to estrogen).
Theca externa (THEE-kuh eks-TUR-nuh): The outer, primarily fibrous and less vascularized layer of dense connective tissue that surrounds the theca interna of the developing follicle; it provides structural support to the follicle and anchors it to the surrounding ovarian stroma.
Cumulus oophorus (KYOO-myoo-lus oh-uh-FOR-us): A mound of granulosa cells that surrounds and attaches the oocyte to the wall of the secondary (antral) follicle; before ovulation, this mass of cells detaches and accompanies the oocyte.
Corona radiata (kuh-ROH-nuh ray-dee-AH-tuh): The innermost layer of granulosa cells immediately surrounding the zona pellucida of the oocyte after ovulation; these cells are the final barrier the sperm must penetrate for fertilization.
Peg cell (peg sell): Non-ciliated, secretory cells found within the lining epithelium of the uterine tube (oviduct); they secrete a fluid that provides nutrients for the oocyte and spermatozoa and aids in sperm capacitation.
Endometrium (en-doh-MEE-tree-um): The highly vascular, inner mucous membrane layer of the uterus; it is composed of a simple columnar epithelium and underlying stroma containing numerous endometrial glands, and it undergoes dramatic, cyclic changes in thickness and structure in preparation for implantation.
Stratum functionalis (STRAT-um funk-shuh-NAL-is): The thick, superficial layer of the endometrium that is rich in endometrial glands and spiral arteries; this layer responds strongly to ovarian hormones and is the portion that is shed during the menstrual phase.
Stroma (of the uterus) (STROH-muh): The specialized connective tissue layer of the endometrium that supports the epithelial lining and endometrial glands; it is characterized by closely packed, small, spindle-shaped cells that resemble lymphocytes.
Stratum basalis (endometrium) (STRAT-um buh-SAY-lis): The thin, deep layer of the endometrium adjacent to the myometrium; this layer is not shed during menstruation and serves as the source of regenerative epithelial and stromal cells needed to rebuild the stratum functionalis.
Endometrial glands (en-doh-MEE-tree-ul glandz): Simple tubular glands that extend from the luminal surface deep into the endometrial stroma; their morphology (straight, coiled, or highly convoluted) changes significantly throughout the menstrual cycle in response to hormones.
Myometrium (my-oh-MEE-tree-um): The thick, middle, muscular wall of the uterus, composed of three poorly defined layers of smooth muscle (bundles of muscle fibers running in various directions); its massive growth during pregnancy is due to both hyperplasia and hypertrophy.
Stratum vasculare (STRAT-um vas-kyoo-LAIR-ee): The thick, middle layer of the myometrium that contains the largest, most abundant blood vessels, specifically the large arcuate arteries and their corresponding veins; this layer is critical for uterine blood supply and controlling postpartum bleeding.
Arcuate arteries (of the uterus) (AR-kyoo-ayt AR-tuh-reez): Large arteries that encircle the uterus within the stratum vasculare of the myometrium; they give rise to smaller radial arteries which supply both the myometrium and the endometrium.
Perimetrium (serosa) (per-ih-MEE-tree-um): The outer, thin layer of the uterus composed of connective tissue covered by a simple squamous epithelium (mesothelium); it is the visceral peritoneum.
Mesothelium (mez-uh-THEE-lee-um): A simple squamous epithelium that lines the serous cavities (like the abdominal cavity) and covers the external surface of visceral organs (e.g., the perimetrium); it secretes a lubricating serous fluid.
Secretory phase (SEK-ruh-tor-ee fayz): The second half of the menstrual cycle, following ovulation, driven primarily by progesterone secreted by the corpus luteum; histologically, the endometrium is thick, edematous, and its endometrial glands become wide, tortuous (saw-toothed), and filled with glycogen-rich secretion.
Spiral artery (SPY-rul AR-tuh-ree): Highly coiled branches of the radial arteries that traverse the stratum basalis to supply the stratum functionalis; their vasoconstriction prior to menstruation causes ischemia and the subsequent shedding of the functional layer.
Proliferative phase (proh-LIF-uh-ray-tiv fayz): The first half of the menstrual cycle (before ovulation), driven primarily by estrogen; histologically, the stratum functionalis is rapidly rebuilt, with endometrial glands appearing straight, narrow, and simple tubular.
Menstrual phase (MEN-strul fayz): The period of the menstrual cycle characterized by the shedding of the stratum functionalis of the endometrium; it is triggered by the breakdown of the corpus luteum and the resulting sharp decline in progesterone and estrogen.
Necrotic tissue (menses) (neh-KRAH-tik TISH-oo): Degenerating and dying epithelial and stromal cells from the stratum functionalis of the endometrium; this tissue is shed along with blood during the menstrual phase.
Extravasated blood (menses) (eks-TRAV-uh-say-ted blud): Blood that has leaked out of damaged spiral arteries and capillaries into the endometrial stroma; this forms the bloody component of the menstrual flow during the menstrual phase.
Cervix (SER-viks): The lower, narrow cylindrical part of the uterus that projects into the vagina; it contains the cervical canal and is composed of dense fibrous connective tissue and a small amount of smooth muscle. It is connected to vagina by the external os and the uterine cavity by the internal os.
Endocervix (en-doh-SER-viks): The inner part of the cervix (the lining of the cervical canal); it is lined by tall, simple columnar epithelium that secretes mucus, as well as deep mucus-secreting endocervical glands.
Transformation zone (cervix) (trans-fer-MAY-shun zohn): The area of the cervix where the stratified squamous epithelium of the ectocervix meets and replaces the columnar epithelium of the endocervix; this area is particularly susceptible to cellular changes and is the most common site for cervical cancer development.
Squamo-columnar junction (cervix) (SKWAY-moh kuh-LUM-ner JUNK-shun): The specific border where the stratified squamous epithelium (from the ectocervix) abruptly meets the simple columnar epithelium (of the endocervical canal); the location of this junction moves throughout life.
Ectocervix (ek-toh-SER-viks): The outer part of the cervix that protrudes into the vagina; it is covered by non-keratinized stratified squamous epithelium, continuous with the vaginal lining.
Mucinous retention cyst (cervix) (Nabothian cyst) (MYOO-sih-nus ri-TEN-shun sist): A small, benign cyst that forms on the cervix when the stratified squamous epithelium of the transformation zone grows over and blocks the opening of a mucus-secreting cervical gland.
Cervical stroma (SER-vih-kul STROH-muh): The bulk of the cervix tissue, composed predominantly of dense connective tissue (fibrous stroma), which provides structural rigidity, with only a minor component of smooth muscle.
External os (ik-STUR-nul ahs): The opening of the cervical canal that leads into the vagina; its shape changes after childbirth.
Cervical gland (SER-vih-kul gland): Simple tubular glands located in the underlying cervical stroma of the endocervix; they secrete thick mucus, the consistency of which changes throughout the menstrual cycle. They empty into the endocervix (and so may be referred to as endocervical glands).
Seminal vesicle (SEM-ih-nul VES-ih-kul): A pair of coiled tubular glands located posterior to the prostate; they secrete a thick, yellowish, fructose-rich fluid that constitutes about 70% of the volume of semen.
Prostate (PROS-tayt): A single gland that encircles the urethra just inferior to the bladder; it secretes a milky, slightly acidic fluid containing citrate and prostate-specific antigen (PSA), which aids in sperm motility and liquefies semen.
Bulbourethral gland (Cowper's gland) (bul-boh-yoo-REETH-rul gland): A pair of small glands located posterior to the membranous urethra; they secrete a clear, alkaline, mucus-rich fluid that lubricates the urethra, glans penis, and neutralizes any residual acidity from urine prior to ejaculation. Homologous to the greater vestibular glands in people with ovaries.
Bulbospongiosus (bul-boh-spun-jee-OH-sus): A paired skeletal muscle that covers the bulb of the penis (in males) or the bulb of the vestibule (in females); in males, it aids in expelling urine and semen from the urethra.
Ductus deferens (Vas deferens) (DUK-tus DEF-uh-renz): A thick-walled muscular tube lined with pseudostratified columnar epithelium with stereocilia; it transports sperm from the epididymis to the ejaculatory duct using strong peristaltic contractions of its smooth muscle layers.
Testis (TES-tis): The male gonad, an endocrine and reproductive organ responsible for producing sperm (spermatogenesis) and secreting male sex hormones (primarily testosterone); it is composed of seminiferous tubules where sperm development occurs.
Epididymis (ep-ih-DID-ih-mis): A highly coiled duct situated along the posterior side of the testis; its function is the storage, maturation, and transport of sperm from the testis to the vas deferens. It contains a head (caput), body (corpus), and tail (cauda) and is lined by a pseudostratified columnar epithelium with stereocilia.
Glans penis (glanz PEN-is): The sensitive, expanded distal end of the corpus spongiosum (spongy urethra runs through it); it is covered by stratified squamous epithelium and is rich in sensory nerve endings.
Corpus spongiosum (KOR-pus spun-jee-OH-sum): A single mass of erectile tissue surrounding the spongy urethra in the penis; it remains pliable during erection, preventing compression of the urethra.
Ejaculatory duct (ih-JAK-yuh-luh-tor-ee dukt): A narrow tube formed by the union of the duct of the seminal vesicle and the ampulla of the vas deferens; it passes through the prostate gland and opens into the prostatic urethra, allowing semen to exit.
Corpus amylacea (prostate) (KOR-pus am-uh-LAY-see-uh): Eosinophilic (pink-staining), laminated concretions (calcified material) commonly found within the acini (glandular spaces) of the prostate gland; their presence often increases with age.
Neuroendocrine cell (prostate) (noor-oh-EN-duh-krin sell): A scattered cell type found within the prostatic epithelium that secretes regulatory peptides and hormones; they are involved in local paracrine control of glandular function and growth.
Luminal cell (prostate) (LOO-mih-nul sell): The main secretory epithelial cell type that lines the prostatic gland/acinus; these columnar cells produce and secrete prostatic fluid components, such as prostate-specific antigen (PSA).
Stromal cell (prostate) (STROH-mul sell): The cell type (primarily fibroblasts and smooth muscle cells) that constitutes the connective tissue support structure, or fibromuscular stroma, of the prostate gland; they are involved in regulating the growth and function of the glandular epithelium.
Fibromuscular stroma (of the prostate gland) (fy-broh-MUS-kyoo-ler STROH-muh): The dominant tissue component of the prostate gland surrounding the glands/acini; it is composed of dense irregular connective tissue (fibrous) and abundant smooth muscle (muscular), which contracts during ejaculation.
Prostatic gland/acinus (pros-TAT-ik gland AS-ih-nus): The glandular secretory unit of the prostate gland, lined by secretory luminal cells and basal cells; they produce prostatic fluid, which makes up a significant portion of semen.