Male reproductive system with diagram | Spermatogenesis | Germ cell (or gametes)

Male reproductive system | Spermatogenesis | Germ cell (or gametes)

Male Reproductive System

The male reproductive system consists of :-

  1. A pair of testis
  2. A pair of epididymis
  3. A pair of vas deferens
  4. Urethra
  5. Penis
  6. Accessory glands

Testicle – It is an oval shaped reproductive organ which lies inside the scrotum in human males. Generally they are in pairs (two testicles) and they called as testis. It is the place where the male gametes (sperms) are generated. It is the most external sensual organ. The average weight of each testis is about 0.35 -0.5 ounce (9.922 gram – 14.175 gram). They are usually 5cm in length (long), 3cm in breadth (wide) and 3cm in thickness.

Male reproductive system with diagram | Spermatogenesis | Germ cell (or gametes)
Fig: Male Reproductive System

Microscopic details inside the testis :-

(1) Epididymis- It is attached with the back of testis. It stores spermatozoa (sperms) in a viable but immobile state. It is a long highly coiled tube and acts as a passage for spermatozoa from the testis.

(2) Tunica vaginalis- It is the outer layer of testicle which is made up of abdominal peritoneum. The two different layers of the tunica vaginalis:

• Visceral laminae (lamina visceralis)  The visceral laminae covers the tunica albuginea (i.e., it covers the greater part of the testis) and epididymis and connects the epididymis to the testis by means of certain folds.

• Parietal laminae (lamina parietalis) The parietal lamina is much more extensive than that of the visceral laminae as it extends upward for some distance in front and some more on the medial side of the cord then reaches below the testis.

(3) Testicular lobules- A finger like projection where the seminiferous tubules are stored. There are 250 compartments, each compartment 2-3 seminiferous tubules are stored.

(4) Seminiferous tubules- They produces sperms in testis. These are highly coiled tube. Between the seminiferous tubules. There is a connective tissue called leydig cells. These cells secrete testosterone hormone (maintains the primary and secondary sexual characteristics in males).

• Vas deferens (Sperm duct)- It serves as a passage for sperms into the urethra during ejaculation

• Urethra- Urethra helps to expel the semen from the penis and it also expels urine from the body

• Penis- Penis is the one of the major role in reproduction. It contains spongy tissue and acts as a copulatory organ for males. The average size of penis is about 5.1-5.5 inch which means (12.95-15.97 cm).

• Glans penis- The tip of the penis is highly sensitive and this tip of the penis is called Glans penis. The penis is covered by a loose skin called produce which can be retracted.

• Urethra- It is present inside the penis and serves as a passage for semen during ejaculation to expel the semen from the penis and it also Carrie’s out urine to exterior.

• Spermatozoa (sperm)- The spermatozoa is male gametes which are produced by the testis. It has three parts :-

  1. Head
  2. Neck
  3. Tail

On the tip of the sperm it is covered by a cap like structure which is called acrosome (contains enzymes). It helps the sperm to penetrate inside the ovum (egg of female, female gametes). In one ejaculation about 200,000,000 sperms are gets discharged. When the sperms enters the vagina of the female they moves with the speed of 2mm/minute.

• Bulbourethral gland (Cowper’s gland)- It secretes a white , viscous fluid which acts as a lubricants. As because sperms (Spermatozoa) are unable to move when they are stored in epididymis but by the secretions from the accessory reproduction glands in males, sperms (Spermatozoa) gets activated and motile. Spermatozoa moves by the help of semen. Semen makes the sperm stable and kept moving in the direction of fertilization, without semen the sperms couldn’t move and reach the destination (fertilization place)

• Leydig cell- They are present in the interstitial space of the seminiferous tubules . They secrets juice which provides nourishment to the sperm. They also release the male hormones androgen

• Testosterone- Testosterone regulates the secondary sexual characteristics in male Example:- Growth of beard, mustache, widening of shoulders, deepening of voice, etc.

Formation of sperm:

The process of formation of sperm is called spermatogenesis. The androgen hormone also called as male hormone is responsible for the formation of sperms.

Steps of spermatogenesis:

Step – 1: Spermatogonium at first starts to divide by mitotic division and forms primary spermatocyte.

Step – 2: Primary spermatocyte then completes 1st miosis division and forms secondary spermatocyte.

Step – 3: Secondary spermatocyte then after completing 2nd miosis division forms spermatids.

Step – 4: Spermatids then convert into Spermatozoa by the process called spermiogenesis.

Step – 5: Spermatozoa (sperm) is finally released from the seminiferous tubules by the process called spermiation. The whole process is regulated by GNRH (Gonadotrophin releasing hormone). It has two types:

1. FSH (Follicular stimulating hormone)

2. LH (Luteinising hormone)

Germ cell

These are the specific type of cells produced by the male and female gonads (or the primary sex organs of male and female) responsible for the formation of sperms. They are haploid in nature as they contains half the number of chromosomes present in a somatic cell and which is able to unite from a diploid zygote that leads to the formation of a new male and female individual. They are also called reproductive cells or gametes.

The male germ cell or male gamete is called sperm while the female germ cell or female gamete is called egg or ova or ovum.

1. Sperms are produced in seminiferous tubule by the process of spermatogenesis.

2. Which passes through rete testis into the vasa efferentia.

3. Then from vasa efferentia sperms enters the epididymis.

4. From epididymis the sperms finally reaches the vas deferens where they usually become semen by the secretion of seminal vesicle which is seminal plasma, bulbourethral gland and prostrate gland.

5. From vas deferens it gets ejaculated out through urethra.

6. Sperms get expel from the urethra during ejaculation.

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