Question

In which of the following phase of the estrus cycle, the female receives the male gamete?

• A. Proestrus
• B. Estrus
• C. Metestrus
• D. All of the above

Answer 1

Answer: (B)

Estrus

• The reproductive cycle of the non-primate females is called the estrous cycle. For example, in rats, horses etc.

It can be divided into four phases - proestrus, estrus, metestrus, and diestrus.

• Proestrus stage is the building up phase. The ovarian follicle becomes large and secretes estrogen which is necessary for the preparation of estrus and pregnancy.
• Estrus is the phase when ovulation takes place. It is also known as the period of heat and female is sexually receptive (can receive the male gamete).
• Metestrus is the phase where the corpus luteum forms under the influence of decreased estrogen and increased progesterone levels.
• Diestrus is the phase where the corpus luteum becomes functional and the progesterone level further increases.

So, the correct option is B.