Male Reproductive System Anatomy Quiz

Male Reproductive System Anatomy

• The male reproductive system is composed of external and internal organs
• External genital organs include the scrotum and penis
• Internal genital organs include the testes, epididymis, vas deferens, ejaculatory duct, seminal vesicles, prostate gland, and bulbourethral glands (Cowper's glands)
• The testes are the primary sex organs, oval-shaped, located in the scrotum.
• They produce sperm and testosterone, the male sex hormone responsible for secondary sex characteristics.
• The testicular artery supplies blood, a direct branch of the aorta.
• Each testis comprises 250-300 lobules, housing 1-4 tightly coiled seminiferous tubules.
• The tubules' contents empty into a rete testis network.
• Small efferent ductules connect the rete testis to the epididymis' upper end.
• Testis coverings include tunica vaginalis (lower portion of processus vaginalis), tunica albuginea (tough, white fibrous outer coat), and tunica vasculosa (vascular connective tissue).
• Seminiferous tubules contain germ cells (spermatogonia, spermatocytes, spermatids) and Sertoli cells (supporting cells).
• Sertoli cells provide nourishment and structure support, forming a blood-testis barrier.

Thermoregulation

• Spermatogenesis requires a temperature 2-3°C below body temperature, maintained through:
• Cutaneous mechanism: scrotal skin's high vascularity and sweat glands aid heat loss.
• Muscular mechanism: dartos and cremaster muscles adjust testis position based on temperature.
• Vascular mechanism: pampiniform plexus minimizes heat transfer to the testes.

Epididymis

• The epididymis is a highly coiled tube connected to the posterior-lateral aspect of the testis.
• It stores sperm for 40-60 days; un-ejaculated sperm are absorbed.
• The epididymis facilitates sperm maturation.
• It absorbs fluid to concentrate sperm.

Vas Deferens

• A thick-walled muscular tube originating from the epididymis' lower end, extending behind the bladder's base.
• It connects to the seminal vesicle duct to form the ejaculatory duct.
• Its length is ~45 cm.
• Transports spermatozoa from the epididymis to the ejaculatory duct for onward travel to the prostatic urethra.

Ejaculatory Ducts

• Formed by the union of the vas deferens and the seminal vesicle duct.
• They run through the prostate's medial-posterior lobes.
• Open into the prostatic urethra.

Scrotum

• An outpouching of the anterior abdominal wall's lower portion.
• Houses the testes, epididymides, and lower spermatic cord ends.
• Pigmented and rugose (wrinkled) skin.

Penis

• Male copulatory organ.
• Features a root (attached portion) and shaft (free portion).
• The root consists of two crura and a bulb.
• The shaft is made up of three columns of erectile tissue: two corpora cavernosa dorsally positioned alongside a corpus spongiosum ventrally.
• Erection involves engorgement of these tissues with blood.
• The glans penis is the distal end of the corpus spongiosum and is covered by the foreskin (prepuce).

Circumcision

• Removal of the foreskin (prepuce) and can result in phimosis (narrow foreskin opening).
• Phimosis potentially interferes with urination or sexual function.

Accessory Glands

• These include the prostate, bulbourethral glands, and seminal vesicles.

Prostate Gland

• Surrounds the prostatic urethra in the lesser pelvis.
• Lies behind the inferior bladder border and in front of the rectum.
• Produces a thin, milky fluid added to semen, which is alkaline to neutralize vaginal acidity.
• Crucial for seminal fluid composition and PSA.

Bulbourethral Glands (Cowper's Glands)

• Located near the penis base; ducts enter the penile urethra.
• Secrete an alkaline mucus-like fluid to neutralize vaginal acidity. Promotes lubrication during intercourse.

Seminal Vesicles

• Sacculated tubes (~5 cm long), positioned behind the bladder's base.
• Narrow into a duct that joins the vas deferens to form the ejaculatory duct.
• Produce an alkaline secretion abundant in fructose and mucus.
• Added to the spermatozoa in ejaculation.

Prostate Examination

• The prostate can be evaluated clinically through palpation during a rectal examination.
• The examiner's gloved finger feels the prostate's posterior surface via the anterior rectal wall.

Further Study Questions

• Precise locations of ejaculatory duct openings and locations,
• Structures composing the penis and their functions,
• Location of seminal vesicles and bulbourethral glands,
• Detailed functions of the prostate and bulbourethral glands.

Test your knowledge about the anatomy of the male reproductive system with this informative quiz. It covers the external and internal organs, their functions, and the anatomy of the testes. Prepare to delve deep into the details of male reproductive anatomy!