Human Reproduction Test - 7

Mitochondria are called power-house of the cell. Sperms need energy for active movement. Middle piece of sperm contain large number of mitochondria.

Half of the sperm contain X-sex chromosome and remaining half contain Y-sex chromosome. Hence two kinds of sperms are formed by human male.

The ovum released during ovulation undergoes several changes and change into corpus luteum that release two hormone, estrogen and progesterone.

Each spermatid undergoes metamorphosis to develop into spermatozoa or sperms having head, neck and tail. Acrosome is present at the tip of head that contain enzyme for hydrolysis of wall of ovum during fertilisation.

During oogenesis reduction division occurs in primary oocytes to produce one polar body and secondary oocytes. Polar bodies further divide to form two polar bodies. Secondary oocytes further divide to produce one polar bodies and a secondary follicle to produce ovum.

In single insemination during coitus about 200-300 millions of sperms are released in the vagina of female. About 60% of them must have normal shape and size along with vigorous motility for fertilisation of ovum.

Meroblastic is the type of incomplete cleavage that occurs in very yolky eggs, in which the egg cytoplasm but not the yolk divides.

Spermiation is the process of release of sperms from Sertoli cells into the cavity of seminiferous tubules.

Ovary contains large number of Graafian follicle that maturates to produce ovum or egg. A small cavity is present in Graafian follicle called antrum.

An egg or sperm only has half of the parent's sex chromosome pair. An egg will always have an X chromosome, since the woman's sex chromosome pair only has Xs. Sperm can have either an X chromosome or a Y chromosome. If Y-chromosome containing sperm fertilize the ovum results is male.