Male Reproductive System

• The testes are the male gonads, which produce sperm cells.
• The seminiferous tubules are responsible for the production of sperm through a process called spermatogenesis.
• Testosterone is the primary male sex hormone responsible for the development of secondary sexual characteristics and the maintenance of reproductive tissues.
• The tunica albuginea is a dense connective tissue that surrounds the testis and provides structural support.
• Spermatogenesis is the process by which sperm cells develop from germinal epithelium cells within the seminiferous tubules.
• Each testis contains about 250 coiled seminiferous tubules that contain sperm-producing cells called sertoli cells.
• Leydig cells surround the seminiferous tubules and secrete hormones such as testosterone to stimulate sperm production.
• Sertoli cells support the development of germ cells (sperm) by providing nutrients and protecting them from damage.
• Leydig cells secrete hormones that stimulate the growth and maturation of sperm cells.
• Interstitial cells also known as Leydig cells, secrete testosterone into the bloodstream to regulate secondary sex characteristics such as muscle mass, bone density, and body hair.
• In dogs, the ventral surface of the os penis is grooved for the urethra.
• The preputial orifice is the opening of the prepuce to the outside.
• The penis, in situ and cross section, and os penis are shown in Figure 6.
• The ischiocavernous muscle is a short skeletal muscle covering the crus of the penis, arising from the ischiatic arch and inserting on the cavernous body.
• The os penis of carnivores is sometimes referred to as “prospector’s toothpick”.
• The bulbus glandis is a part of the glans penis surrounding the proximal os penis, and is responsible for the “tie” or coital lock in dogs.
• VANA 2200 refers to Gross Veterinary Anatomy of the Male Reproductive System.
• The male copulatory organ consists of an inner lamina continuous with the skin over the glans penis, and an outer lamina continuous with the skin on the abdomen.
• The bulbospongiosus muscle is a paired skeletal muscle covering the bulb of the penis.
• The retractor penis muscle is a paired smooth muscle originating from the first caudal vertebra, traveling laterally around the rectum and then continuing side by side over the urethral surface of the penis to attach distally.
• The epididymis is an elongated structure located on the posterior surface of the testis where sperm maturation occurs.
• The epididymis is an elongated tube located on top of the testis where mature sperm cells undergo maturation and storage.
• The rete testis is a network of irregular, interconnecting channels continuing as the straight seminiferous tubules through the mediastinum to the efferent duct.
• The spermatic cord is the structure extending from the testicle through the inguinal canal, consisting of the ductus deferens, testicular vessels and nerves and the lymphatics and their serous coverings.
• Sperm mature in the head and body of the epididymis and are transferred to the deferent duct as fertile sperm.
• In chronological order, the route of the sperm is: Seminiferous tubules - Rete testis - Efferent duct - Epididymis - Ductus deferens - Vas deferens - Urethra.
• The parietal vaginal tunic is the continuation of the abdominal parietal peritoneum through the inguinal canal, it surrounds the visceral vaginal tunic - covered spermatic cord and testicle.
• The vaginal tunic is a double wall of serous membrane (visceral and parietal) around the spermatic cord and testicle in the male and the round ligament of the uterus in female.
• The proper ligament of the testis connects the tail of the epididymis to the ventral extremity of the testis.
• The epididymis is the structure adjacent to the testes, consisting of a head, body, and tail.
• The testis is separated from the rest of the body by septa.
• The efferent duct consists of 8-15 channels leading into the head of the epididymis which unite to form the epididymis.
• The ligament of the tail of the epididymis and scrotal ligament connects the tail of the epididymis to the tunica vagina parietalis.
• The major parts of the seminiferous tubule are the convoluted seminiferous tubules where sperm production occurs and the straight seminiferous tubules which are the short, straight part near the mediastinum and do not produce sperm.
• The male reproductive system consists of the testes, epididymis, deferent duct, urethra, penis and accessory sex glands.
• The testes are located in the scrotum, which is a pouch of skin where the testes are located.
• The epididymis is a coiled tube that sits on top of the testicle and serves as a storage area for mature sperm cells.
• Spermatozoa (or sperm) are produced by the testes and stored in the epididymis until they are ready to be ejaculated during sexual intercourse or masturbation.
• The vas deferens carries mature sperm from the epididymis to the urethra.
• The scrotum is composed of the skin, tunica dartos, spermatic fascia, cremaster muscle, tunica albuginea (white tunic), mediastinum testis, and lobules.