Question

Withdrawal of which hormone is the immediate cause of menstruation?
A)Estrogen
B)FSH
C)FSH-RH
D)Progesterone

Answer 1

Hint: Menstrual cycle is defined as the cycling changes in the reproductive tract of female primates, e.g.
monkeys, apes and human beings. Menstruation is termed as the period of shedding of the
endometrium of the uterus with bleeding

Complete answer:
1.In a normal healthy woman, menstruation occurs at the time period of about 28/29 days. Menarche is defined as the starting of menstruation in girls at puberty.

2.Menstrual cycle is composed of menstrual phase, proliferative phase or follicular phase and secretory or luteal phase.

3.Proliferative phase takes place from 5th to 14th day and consists of growth of endometrium of the uterus, fallopian tube and vagina.

4.In ovary, a Graafian follicle secretes oestrogen at the time of this phase and this hormone remains active throughout this phase. The ovum is taken out from the follicle near the exit of the proliferative phase, i.e. 14 th day or during the midway during the cycle. The ovulation takes place under the influence of LH from pituitary.

5.The subsequent phase of 14 days in which the Corpus luteum is termed to as the secretory phase. Progesterone synthesized by corpus luteum is active during this phase. The endometrium and glands develop further during the secretory phase. At the exit of the secretory phase, corpus luteum degenerates into the corpus albicans in the ovary. Progesterone synthesis decreases and the overgrown endometrium breaks down and menstruation takes place.

Hence, the correct answer is option (D)

Note: Menstrual cycle is regulated by FSH, LH, estrogen and progesterone. The menstruation and menstrual cycle stop during pregnancy and lactation. Menopause is the time period of life when menstruation stops and usually occurs at the age of 50.