Male Genital Organs: Anatomy and Function
Male Genital Organs: Anatomy and Function
External Genitalia
Until recently, determining a baby’s sex at birth involved observing their genitals. Now, ultrasounds allow for prenatal sex determination, but genital observation remains key. Genitals are also called sexual or reproductive organs. While external genitalia are crucial for sex determination, internal organs also play a vital role.
The visible male genital organs are the penis and scrotum. The internal organs—testes, epididymis, vas deferens, seminal vesicles, prostate, and urethra—will be discussed later.
The Penis
The penis, also known as the penis, dick, cock, or tail, is the copulatory organ responsible for depositing semen into the vagina. It’s a complex organ located on the anterior wall of the pelvis. In a resting state, it is soft and mobile. It consists of three cylindrical bodies: two corpora cavernosa and a spongy body. The spongy body ends at the tip, forming the glans penis (or glans), one of the most sensitive areas of the male body. Small grains in this area are usually insignificant.
The urethral meatus, the opening of the urethra, is located on the glans. The urethra carries both urine and semen, but a regulating mechanism prevents them from mixing. The penis is covered by elastic skin with a mobile foreskin covering the glans. The foreskin is connected to the glans by the frenulum, a thin ligament. A greasy, white substance with a characteristic odor forms under the foreskin and requires regular hygiene.
- The penis contains the urethra, which carries semen and urine.
- The meatus, at the glans tip, is the exit for urine and semen.
- The frenulum is a ligament connecting the foreskin to the glans.
The size, shape, and color of the penis vary greatly; no two are alike. Boys should not worry if their penis looks different from others.
The Scrotum
The scrotum is a skin sac divided into two chambers containing the testes. Its function is to protect the testes. The scrotum shrinks in response to cold temperatures or sexual arousal. It has a rugged appearance with deep folds and a seam-like line in the middle. Its tone is slightly darker than the rest of the body. At puberty, the skin thins and becomes hair-covered.
Internal Genitalia
Testicles
The testicles (or testes), also called gonads or “eggs,” are the male sex glands located below the penis. Their external location is crucial for proper function, as they require a temperature lower than the body’s core temperature. They have two functions: reproductive and hormonal.
They produce sperm and hormones, including testosterone, which activate male sexual functions. This process begins at puberty and continues throughout life under the control of the pituitary gland. The testes continuously produce hormones and sperm, regardless of sexual activity.
What do they look like?
The testes are egg-shaped, protected by membranes and skin (the scrotum being the most visible). Their size varies, but they generally resemble plums, are smooth and hard, and the left testicle is usually lower than the right. They are highly sensitive to shocks and pressure. The interior contains seminiferous tubules that connect to larger ducts leading to the epididymis.
The testes may rise and fall due to stimuli like cold, sexual excitement, or touch, caused by scrotum muscle contractions. This is normal. Tight clothing can raise testicle temperature, which is not recommended.
The Epididymides
Located on the back of each testicle, the epididymis (meaning “upon the testicle”) is a crescent-shaped structure and the first part of the spermatic duct. It’s divided into head, body, and tail sections. The epididymis continues into the vas deferens.
The Vas Deferens
These two channels carry mature sperm to the seminal vesicles. The vas deferens enters the prostate and opens into the urethra, which connects to the urinary bladder and genital tracts. Valves regulate the flow of urine and seminal fluid.
The Seminal Vesicles
These sacs, located under the urinary bladder, receive mature sperm. They produce a viscous seminal fluid that nourishes, protects, and facilitates sperm movement.
The Prostate
This male gland is located between the urinary bladder, urethra, and rectum. The prostate and seminal vesicles converge toward the urethra. Valves prevent urine and semen from mixing. The prostate secretes a viscous, white fluid that, along with seminal fluid and sperm, forms semen.
- The prostate produces prostatic fluid that protects, nourishes, and facilitates sperm mobility.
The Urethra
Located above the bladder, the urethra is a tube that runs through the prostate to the glans penis, widening to form the meatus, the exit for urine and semen.
- The urethra carries sperm or urine to the urinary meatus for expulsion.
Cowper’s Glands
These two small organs, located under the prostate, secrete a fluid into the urethra during sexual arousal. This fluid cleans and lubricates the urethra for ejaculation. This secretion may contain sperm, so pregnancy is possible even without ejaculation inside the vagina.
Sperm
Sperm are male reproductive cells. Mature sperm have a head, body, and tail. To reach the egg, sperm lose their fat layer and develop a tail for faster movement. Sperm can remain active for about three days in the female genital tract, but have been found alive in the cervix up to eight days after ejaculation. Maturation takes over seventy days. Each cubic centimeter of semen contains about twenty million sperm. Stress, ejaculation frequency, and diet can affect sperm concentration.
Semen is a bacteria-free fluid composed of spermatozoa, seminal fluid, and prostatic fluid. Sperm travel from the testicles to the seminal ampulla, then through the prostate and penis.