O VUM Kaitlyn Beaulieu

WHERE ARE THEY FOUND?

Enclosed within the egg follicles of the ovaries Measuring about 0.2 mm. in diameter

W HAT DO THEY DO ?

- Within a few hours of fusion of the sperm and the ovum, cell division begins.

- The number of cells doubles with each successive division until a hollow ball of rapidly dividing cells is produced.

- Throughout the process, the ovum is moving down the Fallopian tube toward the uterus.

- Five to six days after the fusion, the ovum reaches the uterus and implants itself in the soft wall.

- The hollow ball of cells now contains up to one hundred cells, arranged as an outer ring and an inner mass.

- These two layers become separated form the outer ring and by nine days form two cavities with the hollow ball. - The ectoderm later spreads around the periphery of the smaller cavity, forming a sac, the amnion, which will surround and protect the developing embryo. - The endoderm similarly encloses the larger cavity to form a yolk sac, which will have a nutritive function.

SPECIAL STRUCTURES

I n appearance and structure the ovum is different from an ordinary cell, but distinctive names have been applied to its several parts The cell substance is known as the yolk The nucleus as the germinal vesicle The nucleolus as the germinal spot

DISEASES

Hormonal Problems Scarred Ovaries Premature Menopause Follicle Problems