Question

In an experiment, sperms removed from the epididymis of a man were added to a dish containing appropriate culture media and oocyte. No fertilisation was observed. However, when sperms from the epididymis were directly placed in the uterus of an ovulated woman, she became pregnant. These observations suggest that

• A. Sperms need to travel some distance to attain fertilising ability
• B. Oocyte secretes some biochemicals or factors which help sperms to fertilise
• C. Hormones in the body help sperms to attain the fertilising ability
• D. Contents of the female reproductive tract interact with sperms and activate them for fertilisation

Answer 1

The correct option is D Contents of the female reproductive tract interact with sperms and activate them for fertilisation

Spermatozoa are commonly said to be mature when they leave the epididymis but there are some changes that happen to the sperms while going through the female genital tract. These changes enable the sperms to fertilise an ovum. Secretions of the female genital tract remove coating substances on the surface of the sperm’s head deposited particularly those on the acrosome. This makes the receptor on the acrosome active to penetrate the egg. The uterine and fallopian tube fluids actually cleanse the inhibitory factors that suppressed the sperm activity when they were in the male genital tract. This phenomenon of sperm activation in mammals is known as capacitation.