The diagram shown below is the longitudinal section of a testis of man. Study it carefully and answer the questions that follow: The diagram shown below is the longitudinal section of a testis of man. Study it carefully and answer the questions that follow:
State the functions of the parts labelled 1 and 3 in the diagram.
Topic: Functions of the scrotum and epididymis
Answer
SCROTUM (part 1): a thin-walled sac of skin that PROTECTS the testes and, by hanging outside the abdominal cavity, keeps them at a temperature about 2–3°C BELOW body temperature — which is necessary for the formation of healthy sperms.
EPIDIDYMIS (part 3): it STORES the sperms for some days while they MATURE and gain the ability to swim, and then passes them on to the vas deferens.
For the SCROTUM the TEMPERATURE point is the one that earns the mark — protection alone is too vague, since any sac protects.
THE EVIDENCE that temperature is the reason: if a testis fails to descend and remains in the abdomen (CRYPTORCHIDISM), it cannot produce sperms at all and the man is sterile unless it is corrected. The position of the scrotum is not an accident of anatomy but a requirement of physiology.
For the EPIDIDYMIS, note that sperms leaving the seminiferous tubules are not yet able to swim. They acquire motility during their days in the epididymis — which is why it is so long (several metres uncoiled) and so tightly coiled.