Question

Estrous cycle is indication of

• A. Breeding period
• B. Estrogen secretion
• C. Menopause
• D. Pregnancy

Answer 1

The correct option is A Breeding period

The recurring physiological changes induced and regulated by reproductive hormones in non-primates constitute oestrous cycle. It consists of short period of heat generation which is then followed by anoestrous phase. Oestrous cycle is initiated as a result of no fertilization and is characterized by sloughing off of uterine endometrium, which was proliferated for implantation of fertilized egg, and its reabsorption. Since, non primate females become receptive to male during oestrous phase, it is indicator of breeding period. Estrogens are secreted by developing follicles in ovary during follicular phase coincide with first oestrous (low estrogens) and then proliferative phase (high level of estrogens by developing follicles) in uterus.This makes option B incorrect since, estrogens level is low during oestrous cycle.

Menopause is the cessation of monthly cycle wherein ovaries do not respond to gonadotropic hormones produced by the anterior pituitary and do not secrete estrogens and progesterone, it is unique to primate females while oestrous cycle is unique to non primates which makes option C incorrect. Pregnancy is marked by cessation of oestrous cycle, option D is incorrect. Therefore, the correct answer is option A.