Male Reproductive Anatomy

Anatomy

• The male testis is a paired organ located outside the abdominal cavity in the scrotum
• Each testis is approximately 2 inches (5 cm) long and 1 inch (2.5 cm) in diameter
• The testis is surrounded by a fibrous capsule called the tunica albuginea
• The testis is divided into lobules, each containing 1-4 seminiferous tubules
• The seminiferous tubules are lined with Sertoli cells and germ cells (spermatogonia, spermatocytes, spermatids)
• The interstitial tissue between the tubules contains Leydig cells

Function

• The primary function of the testis is to produce spermatozoa (sperm) through a process called spermatogenesis
• The testis also produces androgens, such as testosterone, which are essential for male development and fertility
• The testis plays a crucial role in the regulation of reproductive function and secondary sex characteristics

Development

• The testis develops from the genital ridge during embryonic development
• The primordial germ cells migrate to the genital ridge and differentiate into spermatogonia
• The testis descends into the scrotum during fetal development
• The testis continues to mature and develop after birth, reaching full function at puberty

Hormone Regulation

• The testis is regulated by the hypothalamic-pituitary-testicular (HPT) axis
• The hypothalamus produces gonadotropin-releasing hormone (GnRH), which stimulates the pituitary gland to release luteinizing hormone (LH) and follicle-stimulating hormone (FSH)
• LH stimulates Leydig cells to produce testosterone
• FSH stimulates Sertoli cells to support spermatogenesis
• Testosterone and inhibin provide feedback to the hypothalamus and pituitary gland to regulate the HPT axis

Diseases

• Hypogonadism: a condition characterized by low testosterone levels, which can impact fertility and secondary sex characteristics
• Cryptorchidism: a condition where the testis fails to descend into the scrotum, which can increase the risk of infertility and testicular cancer
• Testicular cancer: a rare but highly treatable cancer that affects the testis
• Orchitis: inflammation of the testis, which can be caused by infection or trauma
• Varicocele: a condition characterized by enlarged veins in the scrotum, which can impact fertility

Anatomy of the Testis

• The male testis is a paired organ located outside the abdominal cavity in the scrotum.
• Each testis is approximately 2 inches (5 cm) long and 1 inch (2.5 cm) in diameter.
• The testis is surrounded by a fibrous capsule called the tunica albuginea.
• The testis is divided into lobules, each containing 1-4 seminiferous tubules.
• The seminiferous tubules are lined with Sertoli cells and germ cells (spermatogonia, spermatocytes, spermatids).
• The interstitial tissue between the tubules contains Leydig cells.

Function of the Testis

• The primary function of the testis is to produce spermatozoa (sperm) through a process called spermatogenesis.
• The testis also produces androgens, such as testosterone, which are essential for male development and fertility.
• The testis plays a crucial role in the regulation of reproductive function and secondary sex characteristics.

Development of the Testis

• The testis develops from the genital ridge during embryonic development.
• The primordial germ cells migrate to the genital ridge and differentiate into spermatogonia.
• The testis descends into the scrotum during fetal development.
• The testis continues to mature and develop after birth, reaching full function at puberty.

Hormone Regulation of the Testis

• The testis is regulated by the hypothalamic-pituitary-testicular (HPT) axis.
• The hypothalamus produces gonadotropin-releasing hormone (GnRH), which stimulates the pituitary gland to release luteinizing hormone (LH) and follicle-stimulating hormone (FSH).
• LH stimulates Leydig cells to produce testosterone.
• FSH stimulates Sertoli cells to support spermatogenesis.
• Testosterone and inhibin provide feedback to the hypothalamus and pituitary gland to regulate the HPT axis.

Diseases Affecting the Testis

• Hypogonadism: a condition characterized by low testosterone levels, which can impact fertility and secondary sex characteristics.
• Cryptorchidism: a condition where the testis fails to descend into the scrotum, which can increase the risk of infertility and testicular cancer.
• Testicular cancer: a rare but highly treatable cancer that affects the testis.
• Orchitis: inflammation of the testis, which can be caused by infection or trauma.
• Varicocele: a condition characterized by enlarged veins in the scrotum, which can impact fertility.