Biology
Given below is a diagram of the lateral section of a testis of a man. Study the same and answer the questions that follow:
(i) Label the parts numbered 1 to 4 of the diagram.
(ii) State the functions of the parts labelled 1 and 3.
(iii) What is the significance of the testes being located in the scrotal sac outside the abdomen?
(iv) What is the role played by the inguinal canal?
(v) What is semen?
Answer
(i) The parts numbered 1 to 4 of the diagram are:
- 1 → Seminiferous tubules.
- 2 → Testicular lobes
- 3 → Epididymis
- 4 → Sperm duct/Vas deferens.
(ii) The functions of the parts labelled 1 and 3 are:
- Part 1 (Seminiferous tubules): Seminiferous tubules produce sperms by the process called spermatogenesis.
- Part 3 (Epididymis): The epididymis stores the sperms for some days for maturation and transport it to vas deferens.
(iii) Testes are responsible for the production of male gametes i.e. sperms. The normal body temperature does not allow for the maturation of the sperms. Being suspended outside the body cavity, the temperature in the scrotal sac is 2 to 3°C lower than that of the body which is the suitable temperature for the maturation of the sperms.
When it is too hot, the skin of the scrotum loosens so that the testes hang down away from the body. When it is too cold, the skin contracts in a folded manner and draws the testes closer to the body for warmth.
(iv) Inguinal canal allows the descent of testes along with their ducts, blood vessels and nerves, etc. The sperm duct from each Testis travels upwards into the abdomen passing through the Inguinal canal.
(v) Semen is the mixture of sperms and secretions from seminal vesicles, prostrate and cowper's glands. It is a milky fluid.
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