Question

In human female, the implantation of fertilised egg in the uterus takes place under the influence of

• A. Luteinizing hormone
• B. Follicular stimulating hormone.
• C. Oxytocin
• D. Progesterone

Answer 1

Answer: (D)

FSH, secreted by anterior pituitary gland, stimulates growth, development and hormonal secretion of Graafian follicle and ovum maturation. LH is secreted by anterior pituitary and serves to inhibit secretion of FSH, stimulate maturation and rupture of Graafian follicle and release of ovum i.e. ovulation. This makes options A and D incorrect as FSH and LH are maintained at lower level by negative feedback of estrogen and progesterone hormones on anterior pituitary to prevent maturation of second follicle during pregnancy. If fertilization is followed by implantation, the placental hormone human chorionic gonadotropin maintains the corpus luteum which in turn continues to secrete progesterone to maintain the uterine endometrium and inhibit menses for about 6 months till placenta starts secretion of progesterone and estrogens. Once placenta starts secretion of progesterone, corpus luteum is degenerated into corpus albicans. This makes option C correct as lower levels of progesterone can cause abortion/miscarriage due to disintegration of endometrium which means that corpus luteum is necessary to maintain pregnancy. Option B is incorrect as oxytocin (OT) stimulates uterine muscle contraction during child birth and initiates release of milk by mammary gland. Correct answer is C.