Male Reproductive System: Parts, Functions, Diagrams

Male Reproductive System includes external organs like the penis, scrotum and testicles and internal organs like; the vas deferens, prostate and urethra. Unlike Female Reproductive System, the male reproductive system is an external body part. Apart from these components, the male reproductive system also includes seminal vesicles, prostate glands, and bulbourethral glands, which perform various functions in the body. Read the article to find more about the male reproductive system definition, the diagram, parts and its functions.

What is Reproduction?

Reproduction is the process in which an organism produces a new offspring or individual of its own kind.

Reproduction is of two types:

1. Asexual Reproduction
2. Sexual Reproduction

The fusion of male and female gametes is not involved in asexual reproduction. There is just one parent involved, and the offspring is genetically identical to the parent.

Sexual reproduction is a biparental type of reproduction that involves the production of gametes and there is a fusion of male and female gametes to produce a diploid zygote.

What is Male Reproductive System?

The human male reproductive system is a group of organs that takes part in the process of reproduction and produces gametes. The male reproductive system consists of a pair of the testis, the duct system, accessory glands, and external genitalia. 

Diagram of Male Reproductive System

Let us understand in detail the male reproductive system through the diagram given below:

Parts of Male Reproductive System

Below we have provided information about the parts of the male reproductive system:

Study Types of Reproduction

Testes

(a) Location of the testes

1. The testicles are oval and located outside the abdominal cavity within a scrotum pouch.
2. In the embryonic stage, the testes are contained within the abdomen. They descended into the scrotum shortly before birth. An abnormal condition results when they do not descend, leading to sterility, i.e., incapability to produce sperms.

How is temperature related to the testes?

Sperms are produced in the testes at a temperature 2 to 3 degrees Celsius lower than the body temperature. This temperature is regulated strangely through the movements of the scrotum wall.
When it is too hot, the skin of the scrotum loosens so that the testes hang down away from the body and when it is cold, the skin contracts in a folded manner and draws the testes closer to the body for warmth.

(b) Structure of Testes

Each testis is 5 cm in length, 2 -3 cm in width and about 3 cm in thickness. It is encased in a capsule is internally partitioned into 15-20 lobules. Each lobule contains.

1. Seminiferous tubules, where the sperms are produced through a process called spermatogenesis.
2. Interstitial cells are packing tissues between the coils of the seminiferous tubules. The interstitial cells, also called Leydig cells, produce the male hormone testosterone.

(c) Microscopic Anatomy of Testis

1. Each testis is oval in shape and measures about 5 cm in length, 2-3 cm in width and about 3 cm in thickness. 
2. The testes are covered by outer fibrous tunica vaginalis, middle tunica albuginea, and inner tunica vasculosa. Internally, the testes are divided into about 250-300 pyramid-shaped compartments called testicular lobules.
3. Each lobule contains 1-3 highly coiled seminiferous tubules, the structural and functional unit of testes.
4. There are over 800 seminiferous tubules in each testis. Internally, seminiferous tubules are lined by germinal epithelium, which consists of 2 types of cells: Sertoli Cells and Spermatogonia.

Ducts

Below we have provided detailed information on ducts in the male reproductive system:

Epididymis

Structure & Function: The epididymis is a single convoluted tubule of about 6 m in length located along the posterior surface of the testes. 

The side of the testis continues the epididymis up to its back from where a distinct tube sperm duct or vas deferens arises. The epididymis internally contains a single coiled tube around 6 meters long which runs from the upper part of the testes to its back and then continues into the sperm duct.

Sperm Duct

Structure & Function: The sperm duct, also known as vas deferens, travels from each testis upwards into the abdomen, passing through an inguinal canal. The inguinal canal originally is the one that allows the descent of testes along with their ducts, nerves, etc.

The two sperm ducts loop over the ureters of their side, come together and join the median duct or urethra at the back of the urinary bladder.

Ejaculatory Duct

Structure & Function: The ejaculatory ducts are paired structures in male anatomy in which each ejaculatory duct is formed by the union of the vas deferens with the duct of the seminal vesicle. They pass through the prostate where it opens into the urethra.

Urethra

Structure & Function: The urinary duct originates from the neck of the urinary bladder and opens to the exterior at the tip of the penis.

It helps in passing out both semen and urine.

It has a short, proximal prostatic urethra, a very short, middle membranous urethra, and a distal, long penile urethra.

Accessory Glands

There are three main male accessory glands in the human male reproductive system:

(a) Seminal Vesicle

1. This is a pair of lobulated glands located between the posterior surface of the urinary bladder and the rectum. A duct from each seminal vesicle joints the corresponding sperm duct before it unites with the urethra.
2. This produces a secretion that serves as a medium for the transportation of the sperms. The mixture of this fluid and the sperms has a milky liquid known as semen.

(b) Prostate Gland

1. A bilobed structure that surrounds the urethra close to its origin from the bladder.
2. It pours an alkaline secretion into the semen as it passes through the urethra. It neutralizes acid in the female’s vagina.

(c) Bulbourethral Glands

1. Bulbourethral glands are also known as Cowper’s gland and these are a pair of exocrine glands present in the male reproductive system.
2. These are two small ovoid glands that open into the urethra just before it enters the penis. The secretion serves as a lubricant.

External Genitalia in Male

Below we have provided information on External Genitalia in Male:

1. The penis is the external genitalia in human males. It is made up of a special erectile tissue that helps in the erection of the penis to facilitate insemination.
2. The enlarged end of the penis called glans penis is covered by a loose form of skin called the foreskin.
3. Under the influence of sexual stimulation, blood flows in a large amount into the penis and enters into the vascular spaces which makes it rigid and erect. Expansion of these compresses the veins, and thus blood cannot drain out. Such a condition of the penis is called an erection.

Spermatogenesis

The process of formation of haploid sperms from the diploid spermatogonium in the testes is called Spermatogenesis.

Different Phases of Spermatogenesis

Spermatogenesis occurs in four main phases:

Learn Concept of Sexual Reproduction

Structure of Human Sperm

1. Human Sperm is the small tadpole-like motile, functional, haploid male gamete produced in the testes by the process called spermatogenesis.
2. The human sperm is microscopic and measures about 40-45 µm in length. Structurally, the sperm is divisible into the head, neck, middle piece and tail.

Head

1. The head is a small, almond-shaped structure located at the tip of the sperm that is covered over by a plasma membrane that encloses the acrosome and nucleus.
2. The acrosome is a cap-like structure present at the tip of the sperm head. It is derived from Golgi bodies of spermatids, which contains enzymes that help in dissolving the egg membrane during fertilization.
3. The nucleus of sperm is called the male pronucleus which has a haploid set of chromosomes to transmit the hereditary characteristics from the male.

Neck

1. The neck is a short narrow part between the head and the middle piece. It contains two centrioles and proximal and distal centrioles.
2. The centriole present towards the nucleus is called proximal centriole, and it is necessary for the first cleavage division of the zygote.
3. The centriole present towards a tail is called distal centriole, and it gives rise to the axial filament.

Middle Piece

The middle piece is a little cylindrical in structure and it encloses the axial filament surrounded by a mitochondrial spiral. This supplies energy for the movement of sperm; hence, the middle piece is known as the engine room.

Tail

1. The tail is a long, slender part of a sperm that is divided into the main piece and end piece.
2. The main piece has an axial filament surrounded by a thin layer of cytoplasm and is enveloped by a thick plasma membrane.
3. The end-piece is the last part of the tail which consists of only axial filament without any coverage. Hence it is also called naked.

Functions of Male Reproductive System

The functions of the male reproductive system are as follows:

1. Testis produces reproductive cells by a process called spermatogenesis and also secretes the male sex hormone – testosterone.
2. Epididymis stores sperms and maturation of sperms takes place here.
3. Vas deferens helps in the storage of maturated sperms and helps in its transmission.
4. Semen is a fluid medium of sperm that nourishes and activates the sperms. It also neutralizes the acidity of urine in the urethra.
5. Seminal vesicle helps in the production of many of the constituent ingredients of semen.
6. Prostate glands help in the production of the fluid that nourishes and transports sperms.
7. Bulbourethral glands secrete mucus that serves for lubrication.

Related Topics to Study

Summary

The male reproductive system involves the testes, spermatic ducts, scrotum, sex glands, and penis. All these organs work together to produce sperms, the male gamete, and other components of semen. The male reproductive system plays a vital role in creating a new human generation. Hence, an individual must maintain very good hygiene for good reproductive health.

Some of the preventive measures to avoid reproductive diseases are drinking plenty of water, using condoms during sex, quitting smoking and consumption of alcohol, etc. One can avoid the transmission of STDs by maintaining good reproductive health.

PRACTICE QUESTIONS RELATED TO THE MALE REPRODUCTIVE SYSTEM

FAQs on Male Reproductive System

Q.1. What are the 5 main parts of the male reproductive system?
Ans: The 5 main parts of the male reproductive system are the testes, scrotum, vas deferens, seminal vesicles, and penis.

Q.2. What are the 4 problems of the male reproductive system?
Ans: The four problems of the male reproductive system are infertility problems, early or delayed puberty, lack of testosterone and lack of secondary sex characters. 

Q.3. What are three things that males should do to care for their reproductive system?
Ans: (i) Regular exercise and yoga (ii) follow a proper diet and (iii) good hygiene.

Q.4. How can you prevent reproductive diseases?
Ans: The reproductive diseases can be prevented by the following methods:
(i) Drinking plenty of water.
(ii) Maintaining good reproductive health and hygiene.
(iii) Using condoms during sex (STDs can be avoided).
(iv) Avoiding the consumption of alcohol and quitting smoking.

Q.5. What is Cryptorchidism?
Ans: In some males, the testes fail to descend to the scrotum. This condition is called Cryptorchidism. Such males are infertile. 

Q.6. What is the normal size of the male reproductive organ?
Ans: The normal size of testes, i.e., each testis is 5 cm in length, 2-3 cm in width and about 3cm in thickness.

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