Question

In 28-day human ovarian cycle, ovulation occurs on

• A. Day 1
• B. Day I0
• C. Day 14
• D. Day 28

Answer 1

Answer: (C)

In 28-day human ovarian cycle, ovulation occurs on day 14.

Ovulation, release of a mature egg from the female ovary; the release enables the egg to be fertilized by the male sperm cells. Normally, in humans, only one egg is released at one time; occasionally, two or more erupt during the menstrual cycle. The egg erupts from the ovary on the 14th to 16th day of the approximately 28-day menstrual cycle. If not fertilized, the egg is passed from the reproductive tract during menstrual bleeding, which starts about two weeks after ovulation. Occasionally, cycles occur in which an egg is not released; these are called anovulatory cycles.

Prior to eruption from the ovary, an egg first must grow and mature. Until stimulated to grow, the primary egg cell passes through a period of dormancy that may last several years. The egg cell is surrounded by a capsule of cells known as the follicle. The follicular wall serves as a protective casing around the egg and also provides a suitable environment for egg development. As the follicle ripens, the cell wall thickens and a fluid is secreted to surround the egg. The follicle migrates from within the ovary’s deeper tissue to the outer wall. Once the follicle reaches the surface of the ovary, the follicular wall thins. Pressure caused by the follicle and fluid against the ovary’s surface causes bulging of the ovarian wall. When the follicle ruptures, the egg and fluid are released along with some torn patches of tissue. The cells, fluid, and egg are directed into the nearby fallopian tube, which serves as a passageway by which the egg reaches the uterus and as a site for fertilization of the released egg by sperm.