Difficulty: Intermediate | Prerequisites: Basic tissue types, urinary system anatomy (Ch. 24, especially urethra), peritoneal relationships
Tags: reproductive system, male reproductive anatomy, female reproductive anatomy, testes, ovaries, spermatic cord, uterus, uterine tubes, penis, clitoris, accessory glands, spermatogenesis pathway, ovum pathway, APK2100c
This chapter covers the anatomy of the male and female reproductive systems, with emphasis on identifying organs, tracing the paths that gametes travel, and understanding how structures relate to one another. You will need to distinguish primary sex organs (gonads) from accessory sex organs, know the route sperm take from production to ejaculation, and be able to track an ovum from the ovary to either discharge or implantation. The male urethra, which you already covered in Ch. 24, reappears here because it is shared between the urinary and reproductive systems.
The male reproductive system centres on the testes (primary organs), which produce sperm that travel through a long duct system (epididymis, ductus deferens, ejaculatory duct, urethra) and receive secretions from three accessory glands (seminal vesicles, prostate, bulbourethral glands). The female reproductive system centres on the ovaries (primary organs), which release ova that travel through the uterine tubes to the uterus, where implantation may occur. Both systems have external genitalia with homologous erectile tissues.
Primary sex organs (gonads)
The organs that produce gametes and sex hormones. Testes in males (produce sperm and testosterone). Ovaries in females (produce ova and oestrogen/progesterone).
Accessory sex organs
All reproductive structures other than the gonads: ducts, glands, and external genitalia that transport, nourish, or protect the gametes.
Seminiferous tubules
Tightly coiled tubes within the testes where spermatogenesis (sperm production) occurs. Lined with spermatogenic cells and sustentacular (Sertoli) cells.
Epididymis
A comma-shaped organ on the posterior aspect of each testis. Sperm mature and gain motility here. Consists of head, body, and tail.
Ductus deferens (vas deferens)
A muscular tube that propels sperm from the epididymis up through the inguinal canal and into the pelvic cavity, where it joins the duct of the seminal vesicle to form the ejaculatory duct. This is the duct that is cut during a vasectomy.
Spermatic cord
A bundle of structures passing through the inguinal canal. It contains the ductus deferens, testicular artery, pampiniform plexus of veins, nerves, and lymphatics, all wrapped in connective tissue and muscle layers.
Pampiniform plexus
A network of veins surrounding the testicular artery within the spermatic cord. It acts as a countercurrent heat exchanger, cooling arterial blood before it reaches the testes. This is essential because spermatogenesis requires a temperature 2–3°C below core body temperature.
Seminal vesicles
Paired glands posterior to the bladder. They produce about 60% of semen volume: a viscous, alkaline fluid rich in fructose (energy for sperm), prostaglandins, and clotting proteins.
Prostate gland
A single, walnut-sized gland inferior to the bladder, surrounding the prostatic urethra. It secretes a slightly acidic, milky fluid containing citrate, enzymes (PSA), and fibrinolysin (liquefies clotted semen).
Bulbourethral glands (Cowper's glands)
Paired, pea-sized glands inferior to the prostate. They secrete a clear, alkaline mucus that neutralises residual urine in the urethra and provides lubrication before ejaculation.
Ovary
The female gonad, located in the pelvic cavity on either side of the uterus. It contains ovarian follicles at various stages of development, a cortex, and a medulla. Held in place by the ovarian ligament, suspensory ligament, and mesovarium (part of the broad ligament).
Uterine tube (fallopian tube / oviduct)
A tube extending from near the ovary to the uterus. Regions: infundibulum (with fimbriae that sweep the ovulated oocyte inward), ampulla (widest portion, usual site of fertilisation), isthmus (narrow portion near the uterus).
Uterus
A thick-walled, muscular organ in the pelvic cavity. Regions: fundus (dome above the uterine tube openings), body (main portion), cervix (narrow inferior neck opening into the vagina). Wall layers: perimetrium (serosa), myometrium (thick smooth muscle), endometrium (mucosal lining that sheds during menstruation and is the site of implantation).
Vulva (pudendum)
The external female genitalia: mons pubis, labia majora, labia minora, clitoris, vestibule (containing the urethral and vaginal orifices), vestibular glands (greater/Bartholin's and lesser).
Males:
Primary: testes
Accessory: epididymis, ductus deferens, ejaculatory ducts, urethra, seminal vesicles, prostate gland, bulbourethral glands, penis, scrotum
Females:
Primary: ovaries
Accessory: uterine tubes, uterus, vagina, external genitalia (vulva), mammary glands
This sequence is a classic exam question. In order:
Seminiferous tubules (within the testes; sperm are produced here)
Straight tubules (tubuli recti)
Rete testis (network of channels in the mediastinum testis)
Efferent ductules (connect the rete testis to the epididymis)
Epididymis (head → body → tail; sperm mature here)
Ductus (vas) deferens (ascends through the spermatic cord and inguinal canal into the pelvic cavity)
Ejaculatory duct (formed where the ductus deferens meets the duct of the seminal vesicle; passes through the prostate)
Prostatic urethra (receives secretions from the prostate)
Membranous urethra (short segment passing through the urogenital diaphragm / external urethral sphincter)
Spongy (penile) urethra (runs through the corpus spongiosum of the penis)
External urethral orifice (tip of the glans penis)
A mnemonic: Seven Sleepy Rabbits Eat Enormous Dumpling Eggs Properly Mashed Sometimes Every day (Seminiferous tubules, Straight tubules, Rete testis, Efferent ductules, Epididymis, Ductus deferens, Ejaculatory duct, Prostatic urethra, Membranous urethra, Spongy urethra, External urethral orifice). Use whatever works for you.
The scrotum is an external pouch of skin and subcutaneous tissue that houses the testes outside the body cavity
Dartos muscle (smooth muscle in the scrotal wall) and cremaster muscle (skeletal muscle from the internal oblique) contract in cold to pull the testes closer to the body and relax in warmth to lower them
Pampiniform plexus: a venous plexus that wraps around the testicular artery in the spermatic cord; acts as a countercurrent heat exchanger, cooling incoming arterial blood by transferring heat to the cooler venous blood returning from the testes
Together, these mechanisms maintain testicular temperature about 2–3°C below core body temperature, which is necessary for viable spermatogenesis
The spermatic cord passes through the inguinal canal and contains:
Ductus (vas) deferens
Testicular artery
Pampiniform plexus of veins (testicular veins)
Testicular nerves (autonomic)
Lymphatic vessels
Cremasteric artery and vein
Artery of the ductus deferens
All wrapped in three fascial coverings derived from the abdominal wall layers
Seminal vesicles: paired, posterior to the bladder; contribute ~60% of semen volume; secrete fructose, prostaglandins, clotting proteins
Prostate gland: single, surrounds prostatic urethra; contributes ~25–30% of semen; secretes enzymes (PSA), citric acid, fibrinolysin
Bulbourethral glands (Cowper's glands): paired, inferior to the prostate; secrete pre-ejaculatory mucus for lubrication and urethral neutralisation
Root: attached to the perineum; includes the bulb (expanded base of the corpus spongiosum) and the crura (paired bases of the corpora cavernosa)
Shaft (body): the free, pendulous portion
Glans penis: the expanded distal end; covered by the prepuce (foreskin) in uncircumcised males
Erectile tissues:
Corpora cavernosa: paired, dorsal cylinders; main erectile bodies
Corpus spongiosum: single, ventral cylinder; surrounds the spongy urethra; expands distally to form the glans penis
Primary: ovaries (paired, almond-shaped, in the pelvic cavity lateral to the uterus)
Accessory: uterine tubes, uterus, vagina, external genitalia (vulva), mammary glands
Held in position by:
Ovarian ligament: anchors the ovary medially to the uterus
Suspensory ligament: anchors the ovary laterally to the pelvic wall; contains the ovarian artery and vein
Mesovarium: a fold of the broad ligament that encloses the ovary
Contains a cortex (with ovarian follicles at various stages) and a medulla (with blood vessels and nerves)
Covered by a germinal epithelium (simple cuboidal, despite the name, is not the source of germ cells) and a deeper tunica albuginea (connective tissue capsule)
Regions (lateral to medial):
Infundibulum: funnel-shaped open end near the ovary, fringed with fimbriae (finger-like projections that create currents to draw the ovulated oocyte into the tube)
Ampulla: widest and longest section; usual site of fertilisation
Isthmus: narrow section that connects to the uterus
Uterine (intramural) part: passes through the uterine wall
Lined with ciliated columnar epithelium that helps move the oocyte toward the uterus via peristaltic contractions and ciliary action
Located in the pelvic cavity between the bladder (anterior) and the rectum (posterior)
Regions: fundus (superior, dome-shaped, above uterine tube openings), body (main portion), cervix (inferior narrow neck; opens into the vagina via the external os)
Wall layers:
Perimetrium: serosa (visceral peritoneum) covering the outer surface
Myometrium: thick layer of smooth muscle; contracts powerfully during labour
Endometrium: mucosal lining with a functional layer (shed during menstruation, site of implantation) and a basal layer (regenerates the functional layer)
Supported by ligaments: broad ligament, round ligament, uterosacral ligaments, cardinal (lateral cervical) ligaments
A muscular, elastic tube from the cervix to the vestibule (external opening)
Lined with stratified squamous epithelium (non-keratinised), adapted to resist friction
Located between the urethra/bladder (anterior) and the rectum (posterior)
Functions: birth canal, passageway for menstrual flow, receives the penis during intercourse
Mons pubis: fatty pad over the pubic symphysis
Labia majora: outer, larger folds of skin and adipose; homologous to the scrotum
Labia minora: inner, thinner folds of skin; enclose the vestibule
Clitoris: small erectile organ at the anterior junction of the labia minora
Composed of: glans, body (shaft), paired crura (legs)
Erectile tissue: paired corpora cavernosa (homologous to the male corpora cavernosa)
No corpus spongiosum; no urethra passes through it
Vestibule: the space enclosed by the labia minora; contains the urethral orifice (anterior) and the vaginal orifice (posterior)
Greater vestibular glands (Bartholin's glands): paired, flanking the vaginal orifice; secrete mucus for lubrication; homologous to the bulbourethral glands
Vestibular bulbs: masses of erectile tissue deep to the labia minora on either side of the vestibule; homologous to the corpus spongiosum/bulb of the penis
From origin to either discharge or implantation:
Ovary: an oocyte develops within a follicle in the ovarian cortex
Ovulation: the mature oocyte (secondary oocyte) is released from the ovary's surface into the peritoneal cavity
Infundibulum of the uterine tube: the fimbriae sweep the oocyte into the tube
Ampulla of the uterine tube: the oocyte travels here; if sperm are present, fertilisation typically occurs at this location
If fertilised: the zygote continues through the isthmus → enters the uterus → the developing embryo (now a blastocyst) implants in the endometrium of the uterine body/fundus (~6–7 days after fertilisation)
If not fertilised: the oocyte degenerates in the uterine tube or uterus and is shed with the endometrial lining during menstruation, exiting via the cervix → vagina → vestibule
Both are erectile organs with homologous tissues:
Similarities:
Both contain paired corpora cavernosa
Both have a glans (glans penis, glans clitoridis) that is highly sensitive
Both have a body/shaft and crura (roots)
Both become engorged with blood during arousal
Differences:
The penis contains a corpus spongiosum surrounding the urethra; the clitoris does not (the urethra does not pass through the clitoris)
The penis is significantly larger and serves dual roles (urination and ejaculation); the clitoris is primarily a sensory/sexual organ
The glans penis is the expanded end of the corpus spongiosum; the glans clitoridis is the exposed tip of the fused corpora cavernosa
An ectopic pregnancy occurs when a fertilised egg implants outside the uterus, most commonly in the ampulla of the uterine tube. Knowing the anatomy of the tube helps you understand why the ampulla is the most likely site (it is where fertilisation happens, and if the embryo implants there instead of continuing to the uterus, the tube cannot sustain it). The pampiniform plexus is clinically relevant because dilation of these veins (a varicocele) can raise testicular temperature and impair fertility.
Students sometimes list the scrotum or penis as primary sex organs. They are accessory organs. Only the gonads (testes and ovaries) are primary.
The oocyte is ovulated into the peritoneal cavity, not directly into the uterine tube. The fimbriae must sweep it in. There is a brief moment when the oocyte is technically "loose" in the peritoneal space.
The clitoris does not contain a corpus spongiosum and the urethra does not pass through it. Students sometimes assume it mirrors the penis exactly.
The ejaculatory duct is short and passes through the prostate. Students sometimes confuse the ejaculatory duct with the ductus deferens; they are different structures.
⚠️ Know the order of structures sperm travel through, from seminiferous tubules to external urethral orifice. This is a heavily tested sequence.
⚠️ Contents of the spermatic cord, especially the pampiniform plexus and its thermoregulatory function.
⚠️ Be able to name each accessory gland and what it secretes (seminal vesicles: fructose; prostate: PSA/enzymes; bulbourethral: mucus).
⚠️ Track the ovum from ovary to implantation or discharge, including where fertilisation normally occurs (ampulla).
⚠️ Compare the penis and clitoris: shared erectile tissue (corpora cavernosa), key difference (corpus spongiosum and urethra present in penis, absent in clitoris).
⚠️ Distinguish primary from accessory sex organs for both sexes.
True or False: The ovaries are accessory sex organs.
Fill in the blank: Fertilisation usually occurs in the __________ of the uterine tube.
True or False: The clitoris contains a corpus spongiosum.
Fill in the blank: The pampiniform plexus functions as a countercurrent __________ exchanger.
True or False: The ejaculatory duct is formed by the union of the ductus deferens and the duct of the seminal vesicle.
Answers: 1. False (they are primary sex organs / gonads). 2. Ampulla. 3. False. 4. Heat. 5. True.
Q: List the structures sperm travel through from the seminiferous tubules to the external urethral orifice.
A: Seminiferous tubules → straight tubules → rete testis → efferent ductules → epididymis → ductus (vas) deferens → ejaculatory duct → prostatic urethra → membranous urethra → spongy (penile) urethra → external urethral orifice.
Q: What are the contents of the spermatic cord?
A: Ductus deferens, testicular artery, pampiniform plexus of veins, testicular nerves, lymphatic vessels, cremasteric artery and vein, artery of the ductus deferens, and fascial coverings.
Q: Explain how the scrotum and pampiniform plexus regulate testicular temperature.
A: The dartos and cremaster muscles in the scrotal wall contract to elevate the testes toward the body in cold conditions and relax to lower them in warmth. The pampiniform plexus surrounds the testicular artery in the spermatic cord and acts as a countercurrent heat exchanger: warm arterial blood transfers heat to the cooler venous blood returning from the testes, so that the blood arriving at the testes is pre-cooled to the 2–3°C below core temperature required for spermatogenesis.
Q: Track an ovum from its origin to either discharge from the body or implantation.
A: The oocyte develops within a follicle in the ovarian cortex → is ovulated into the peritoneal cavity → swept into the uterine tube by the fimbriae of the infundibulum → travels to the ampulla (where fertilisation may occur) → continues through the isthmus into the uterus. If fertilised, the developing blastocyst implants in the endometrium. If not fertilised, the oocyte degenerates and is shed with the endometrial lining through the cervix, vagina, and vestibule during menstruation.
Q: Compare and contrast the penis and the clitoris.
A: Both contain paired corpora cavernosa, a glans, a body, and crura; both become engorged during arousal. The penis additionally contains the corpus spongiosum, which surrounds the urethra and expands to form the glans penis. The clitoris lacks a corpus spongiosum and no urethra passes through it. The penis serves urinary and reproductive functions; the clitoris functions primarily as a sensory organ.
This connects to the Urinary System (Ch. 24) because the male urethra is shared between the urinary and reproductive tracts, and sphincter anatomy applies to both. It also connects to Blood Vessels (Ch. 20) through the pampiniform plexus (a venous heat exchanger) and the gonadal arteries and veins. The concept of intraperitoneal vs. retroperitoneal from the Digestive System (Ch. 23) is relevant here because the ovaries and uterus are intraperitoneal organs suspended by portions of the broad ligament.
reproductive system, male reproductive anatomy, female reproductive anatomy, testes, seminiferous tubules, spermatogenesis, straight tubules, rete testis, efferent ductules, epididymis, ductus deferens, vas deferens, ejaculatory duct, spermatic cord, pampiniform plexus, cremaster muscle, dartos muscle, scrotum, thermoregulation, seminal vesicles, prostate gland, PSA, bulbourethral glands, Cowper's glands, penis, corpora cavernosa, corpus spongiosum, glans penis, ovaries, ovarian follicles, ovulation, uterine tubes, fallopian tubes, infundibulum, fimbriae, ampulla, isthmus, uterus, fundus, body, cervix, endometrium, myometrium, perimetrium, vagina, vulva, mons pubis, labia majora, labia minora, clitoris, glans clitoridis, vestibule, greater vestibular glands, Bartholin's glands, vestibular bulbs, broad ligament, round ligament, ovarian ligament, suspensory ligament, mesovarium, ectopic pregnancy, varicocele