Explain the role of ovarian hormones in inducing changes in the uterus during
menstrual cycle.
(ii) What triggers release of oxytocin at the time of parturition? (3)
Biology question
Answers
With the start of a menstrual cycle, pituitary produces FSH hormone which stimulates the ovaries to start the formation and maturation of eggs. With the maturation of these follicles, estrogen level rises in the body indicating the formation of the mature egg. This leads to the completion of the follicular phase. The pituitary gland now produces LH hormone which causes the release of an egg from ovary by the process of ovulation. After ovulation, luteal phase begins during which the level of progesterone in the body starts increasing. Progesterone hormone maintains the lining of the wall of the uterus for pregnancy. If pregnancy does not take place then progesterone level falls and menstrual flow begins.
Answer:
With the start of a menstrual cycle, pituitary produces FSH hormone which stimulates the ovaries to start the formation and maturation of eggs. With the maturation of these follicles, estrogen level rises in the body indicating the formation of the mature egg. This leads to the completion of the follicular phase. The pituitary gland now produces LH hormone which causes the release of an egg from ovary by the process of ovulation. After ovulation, luteal phase begins during which the level of progesterone in the body starts increasing. Progesterone hormone maintains the lining of the wall of the uterus for pregnancy. If pregnancy does not take place then progesterone level falls and menstrual flow begins.