Male Reproductive Anatomy and Function

Sexual Reproduction Basics

The male and female germ cells are called gametes. They have 23 pairs of chromosomes. This means 46 chromosomes. The chromosomes that make up each pair are called homologous. The sex chromosomes are referred to by the letters X and Y. The other 22 pairs of chromosomes are autosomes.

The gonads are represented by the testes in males and ovaries in females.

Male Reproductive System

The Scrotum

It is a membranous sac that hangs from the root of the penis. From the outside, it appears formed by a layer of skin, divided into two parts (right and left) by a raphe. The interior is divided by a membranous septum and a muscle called the tunica dartos muscle.

The Testicles

They are ovoid structures that are the male gonads, weighing about 10 grams each and measuring about 5-6 cm long and 2.5 cm thick.

Externally, each testicle is covered by an extension of the peritoneum called the tunica vaginalis, and more internally by the tunica albuginea, which extends inward, dividing the structure into compartments called testicular lobes.

Inside the lobes are structures of tubules called seminiferous tubules, which is where sperm are produced. On their walls and among them are sperm-producing cells called Sertoli cells.

In the parenchyma, there are other cells called Leydig cells that are the producers of the hormone testosterone.

Moving inward towards the testicle, one encounters the following structures:

• Scrotal skin
• Tunica Dartos muscle
• Cremaster muscle
• Tunica Vaginalis
• Tunica Albuginea

Epididymis and Vas Deferens

The seminiferous tubules flow into a tubular structure located in the upper pole of each testicle called the epididymis. It forms a kind of cap that surrounds half of the testis from its upper to the lower pole, where it continues as another tubular structure called the vas deferens.

The vas deferens is about 40 cm long, rising into the abdomen near the ureter towards the bladder base. In its final part, there is a dilation called the ampulla.

The Spermatic Cord

The spermatic cord is a support structure that includes:

• The vas deferens
• The testicular artery
• The deferential artery
• Veins from the pampiniform plexus
• Autonomic nerves
• Lymphatics
• The cremaster muscle