Open In App

Male Reproductive System – Structure and Functions

Last Updated : 16 Aug, 2023
Like Article

The male reproductive system is part of a male’s body that is responsible for the production of the male gamete as well as transferring it to the reproductive system of the female. The male reproductive system consists of a pair of testis, accessory ducts, and external genitalia. The majority of the male reproductive system’s parts are located outside the body. In this article, we will study the structure and functions of the male reproductive system.

Human Reproduction

As living organisms, humans reproduce sexually and give birth to live offspring i.e. viviparity. In the process, gametes are formed through gametogenesis, followed by insemination where sperm is transferred into the female genital tract, then comes the fusion of male and female or fertilization of gametes that leads to the formation of a zygote which then develops into a blastocyst that attaches to the uterine wall i.e. implantation, followed by embryonic development and gestation finally ending into birth or parturition. Reproductive events occur after puberty. There are significant differences between the reproductive events in males and females, however, both sexes have primary organs that produce gametes and sex hormones, and secondary organs that don’t produce gametes or hormones but play important roles in the conditioning of sex organs. 

Male Reproductive System

The male reproductive system is mostly located outside the body in the lower abdominal region. It consists of the primary reproductive organ which produces the main sex hormone and sex gametes i.e. the testis along with the accessory reproductive system i.e. the glands, ducts, and external genitalia which helps with the process of maturation and transfer of the male gametes to the female’s reproductive system.

Labeled Diagram of Male Reproductive System

Well labeled diagram of the male reproductive system is shown below:

Structure of Male Reproductive Organs

The male reproductive system is located in the pelvic region. It includes a pair of testes along the accessory ducts, glands, and external genitalia or penis.

Penis (or The Male External Genitalia)

The male external genitalia consists of the penis and scrotum. The penis serves as a urinal duct and transfers spermatozoa to the female vagina. It is composed of three columns of spongy tissues, including two upper corpora cavernosa on the dorsal side and one corpus spongiosum on the ventral side. The corpora cavernosa continues as the glans penis, which is the enlarged and bulbous end of the penis. The glans penis is covered by a loose fold of skin called the prepuce. The urethra runs through the corpus spongiosum, and its opening, called the urethral meatus, is located at the tip of the glans penis. A layer of skin and subcutaneous areolar tissue encloses all three columns of the penis. The corpora cavernosa is composed of a special tissue with spaces that fill with blood to facilitate erections for insemination. 

Testis (or Male Gonads)

The male reproductive primary sex organs are known as the testes or testicles. They are oval and pinkish in appearance and are located outside the abdominal cavity within a pouch called the scrotum. The testes descend into the scrotum just before birth (at the age of 280 days), and the condition in which they do not descend is known as cryptorchidism. A spermatic cord, which comprises the vas deferens, nerves, blood vessels, lymph, lymph vessels, and cremaster muscles, runs from the abdominal wall to each testis through the inguinal canal. In adults, each testis is 4 to 5 cm in length and 2 to 3 cm in width, and each testis is covered by three layers of tissues;

  1. Tunica Vasulose:  It is the innermost loose layer of connective tissue, rich in blood vessels. 
  2. Tunica Albuginea: It is a dense fibrous capsule. It extends inward to form septa that partition the testis into lobules.
  3. Tunica Vaginalis: It is a pouch of the serous membrane (peritoneal layer) called tunica vaginalis ( it is double-layered, enclosing a fluid-filled coelomic cavity) that covers the testis. 

Seminiferous Tubules: In each testis, there are approximately 250 testicular lobules. These lobules contain 1-3 coiled seminiferous tubules each, where sperms are produced. The seminiferous tubules have two types of cells lining their insides: male germ cells (spermatogonia) and Sertoli cells (sustentacular cells). The spermatogonia produce primary spermatocytes, which go through meiotic division to create sperm. Sertoli cells provide nutrition to the spermatozoa and produce inhibin, a hormone that inhibits the secretion of FSH. Facing the lumen of the seminiferous tubule, many spermatocytes and spermatids attach to the apical surface of Sertoli cells. Outside the seminiferous tubules are interstitial spaces that contain Leydig cells or interstitial cells which secrete androgens, with testosterone being the most important. Testosterone controls the development of secondary sexual characteristics and spermatogenesis.

Scrotum: The sac-like structure that contained the testis externally is called the scrotum which helps in maintaining a lower temperature for the testes (2-2.5 C lower than the normal internal body temperature), which is necessary for the process of spermatogenesis. The scrotum is partitioned internally by a muscular septum scroti into right and left scrotal sacs, each of which encloses one testis. Raphe, a vertical marking, is present externally between the two scrotal sacs. The inguinal canal connects the cavity of the scrotal sac to the abdominal cavity. The testes are held in position within the scrotal sac by the gubernaculum, a fibrous cord that connects the testis with the bottom of the scrotal sacs.


Accessory Duct System

The male accessory ducts include rete testis ( a network of tubules in the testis), Vasa efferentia, epididymis, Vasa deferentia, and urethra.

Rete Testis

It is a network of ducts that connects the seminiferous tubules to the vasa efferentia through which the sperm cells pass.

Vasa Efferentia

It is a network of 15 to 20 ducts that leaves the testis and opens into a narrow, long tightly coiled tube called epididymis located along the posterior surface of each testis.


The epididymis has three parts: caput (head), corpus (body), and cauda (tail). Sperm enter into the caput epididymis through the Vasa efferentia and are stored and matured here in the corpus epididymis. Through the cauda epididymis, the sperm cells leave to the vasa deferentia. The epididymis is lined with epithelium cells that provide nutrients to the sperm cells.

Vasa Deferentia

The Vas deferens is a muscle-lined tube that transports sperm from the testis to the outside. It originates from the epididymis, curves around the urinary bladder, and ends at the ampulla where sperm is temporarily stored. The Vas deferens and the duct of the seminal vesicle unite to create a muscular ejaculatory duct/ductus ejaculators, which opens into the urethra inside the prostate gland.



In males, the urethra is the shared (common) terminal duct of the reproductive and urinary systems. The urethra originates from the neck of the urinary bladder and extends through the penis to its external opening called the urethral meatus. The urethra of male human beings is differentiated into the urinary urethra, prostatic urethra, membranous urethra, and penile urethra.

  • Urinary urethra: It is present between the urinary bladder and ejaculatory ducts. It carries urine.
  • Prostatic urethra:- It passes through the prostate gland. It is the first part of the urinal-genital duct.            
  • Membranous urethra: It lies in between the prostate gland and penis. It is the uncovered part of the urethra. Ducts of bulbourethral glands open into the membranous urethra. 
  • Penile urethra: It is the distal part of the urethra that is surrounded by the corpus spongiosum muscles of the penis. Hence it is also called the spongiose urethra. The penile urethra is the longest urethra. 

Sphincters of the Urethra: The urethra has two sphincters namely the external sphincters with straightening voluntary muscles. External sphincter muscle fibers are present around the membranous part. The internal sphincter occurs at the neck of the urinary bladder with smooth involuntary muscles. The urethra provides an exit for urine and semen during ejaculation, in males. 

Glands of the Male Reproductive System

The male reproductive system comprises three main glands; a pair of seminal vesicles, a prostate, and a pair of bulbourethral glands.

Seminal Vesicles

The seminal vesicles are two tubular glands located below the urinary bladder in the pelvis. They are connected to the corresponding Vas deferens, which enter the prostate gland. The seminal vesicles produce about 60 percent of the seminal fluid, a thick, alkaline liquid containing fructose, proteins, citric acid, inorganic phosphorus, potassium, and prostaglandins. When this fluid mixes with sperm in the ejaculatory duct, the fructose provides energy for the sperm.

Prostate Gland

The prostate gland is located directly beneath the urinary bladder. The gland surrounds the prostatic urethra and sends its secretions through several prostatic ducts. The prostate contributes 15 – 30%  of the semen. The prostatic secretion is clear, slightly acidic and activates the spermatozoa, and provides nutrition. 

Bulbourethral Gland

The Bulbourethral glands, also called Cowper’s glands are located beneath the prostate gland at the beginning of the internal portion of the penis. They add an alkaline fluid to semen during the process of ejaculation. The fluid secreted by these glands lubricates the urethra. It is also thought to function as a flushing agent that washes out the acidic urinary residues that may remain in the urethra before the semen is ejaculated. 

Erection of the Penis

The erection of the penis is caused by a rush of arterial blood into the empty sinuses of its spongy tissues on sexual excitement. As the spongy tissue distends, it compresses the veins, inhibiting the flow of blood out of the tissue. The filling of tissue with blood is Called vasocongestion. The erection of the penis is caused by parasympathetic impulses. The release of semen into the proximal part of the urethra by contraction of reproductive glands and ducts is called emission. Rhythmic, wavelike contractions of the muscles at the base of the penis cause forceful discharge of semen into the vagina. This is called ejaculation. Emission and ejaculation are caused by sympathetic impulses. 

Hormones of the Male Reproductive System

The primary hormones that are responsible for controlling the male reproductive system are;

  1. Follicle Stimulating Hormone (FSH): It is responsible for the stimulation of the process of spermatogenesis and is produced and stored in the pituitary gland.
  2. Luteinizing Hormone (LH): It stimulates the Leidig’s cells to produce testosterone which is required to sustain the process of sperm formation. It is also produced and stored in the pituitary gland.
  3. Testosterone: It is the main sex hormone in males that is responsible for the development of sperm cells and secondary sexual characteristics.

FAQs on Male Reproductive System

1. In the male’s reproductive system differentiate between the primary and secondary sex organs.


In the male’s reproductive system, the primary sex organ is the gonads or testis whereas, the accessory duct system, glandular system, and external genitalia or penis comprise the secondary sex organs.  

2. From Seminiferous tubules to outside the body track the pathway of a sperm cell.


The pathway of sperm cells will comprise;

Semeniferous tubules –> rete testis –> vasa efferentia –> epididymis –> vasa deferentia –> urethra –> glans penis –> outside the body

3. What are the two main important functions of the male reproductive system?


The male reproductive organs have two primary functions: 

  • To synthesize sperm cells.
  • To synthesize the male sex hormone the testosterone.

4. Where the sperms stored in?


After the sperm cells production in the seminiferous tubules, they are first stored for maturity in the epididymis. Then they are temporarily stored in the ampulla of the vasa deferentia before release.

Like Article
Suggest improvement
Share your thoughts in the comments

Similar Reads