Chapter 3
Human Reproduction
Basic Steps in Human Reproduction:
1. Gametogenesis
2. Insemination
3. Fertilization
4. Blastocyst development
5. Implantation
6. Embryo development
7. Parturition
3.1: Male Reproductive System
The male reproductive system has four main parts:
1. Testes
2. Accessory ducts
3. Glands
4. External Genitalia
Testes (singular Testis):
• Situated in the pelvic region outside the abdominal cavity within a pouch called as scrotum.
• Scrotum is a small muscular sac that contains and protects the testes. It is a part of the external male
genitalia and is located behind the penis.
• The testes are placed outside the abdominal cavity so as to maintain a temperature that is 2-2.5◦C lower
than the average human body temperature.
• The lower temperature in testes is required for spermatogenesis as the normal human body temperature
can lead to mutation in the sperms.
• Testis is oval in shape. It is 4-5cm long and 2-3cm wide.
• Each testis has about 250 compartments called as Testicular lobules
, • Each lobule contains 1-3 highly coiled seminiferous tubules.
• Seminiferous tubules are the site for meiosis that leads to the formation of spermatozoa.
➢ The inner lining of each seminiferous tubule consists of two types of cells: Spermatogonia and
Sertoli cells.
➢ Spermatogonia are the immature male germ cells that undergo meiosis that leads to formation
of sperms. Each spermatogonium is diploid and contains 46 chromosomes
➢ Sertoli cells provide nutrition to the spermatogonia
➢ Interstitial spaces: These are the regions outside the seminiferous tubules. They contain small
blood vessels, some immunocompetent cells and interstitial cells or the Leydig cells.
➢ Leydig cells: These are the cells that synthesise and secrete testicular hormones called androgens.
Human Reproduction
Basic Steps in Human Reproduction:
1. Gametogenesis
2. Insemination
3. Fertilization
4. Blastocyst development
5. Implantation
6. Embryo development
7. Parturition
3.1: Male Reproductive System
The male reproductive system has four main parts:
1. Testes
2. Accessory ducts
3. Glands
4. External Genitalia
Testes (singular Testis):
• Situated in the pelvic region outside the abdominal cavity within a pouch called as scrotum.
• Scrotum is a small muscular sac that contains and protects the testes. It is a part of the external male
genitalia and is located behind the penis.
• The testes are placed outside the abdominal cavity so as to maintain a temperature that is 2-2.5◦C lower
than the average human body temperature.
• The lower temperature in testes is required for spermatogenesis as the normal human body temperature
can lead to mutation in the sperms.
• Testis is oval in shape. It is 4-5cm long and 2-3cm wide.
• Each testis has about 250 compartments called as Testicular lobules
, • Each lobule contains 1-3 highly coiled seminiferous tubules.
• Seminiferous tubules are the site for meiosis that leads to the formation of spermatozoa.
➢ The inner lining of each seminiferous tubule consists of two types of cells: Spermatogonia and
Sertoli cells.
➢ Spermatogonia are the immature male germ cells that undergo meiosis that leads to formation
of sperms. Each spermatogonium is diploid and contains 46 chromosomes
➢ Sertoli cells provide nutrition to the spermatogonia
➢ Interstitial spaces: These are the regions outside the seminiferous tubules. They contain small
blood vessels, some immunocompetent cells and interstitial cells or the Leydig cells.
➢ Leydig cells: These are the cells that synthesise and secrete testicular hormones called androgens.
