The corpus luteum secretes progesterone which negatively feeds back and inhibits the release of |
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a) |
ABP and ICSH |
b) |
LH and ICSH |
c) |
LH and FSH |
d) |
FSH and TSH |
The corpus luteum secretes progesterone which negatively feeds back and inhibits the release of |
|||||||
a) |
ABP and ICSH |
b) |
LH and ICSH |
c) |
LH and FSH |
d) |
FSH and TSH |
(c)
The corpus luteum secretes progesterone, which negatively feed back and inhibits the release of LH and FSH.
Generally, menstrual cycle have four phases
(i) Menstrual phase (a) The soft tissue of endometrial lining of the uterus disintegrates causing bleeding.
(b) The unfertilized egg and soft tissue are discharged.
(c) It lasts 3-5 days.
(ii) Follicular Phase/Proliferative Phase (a) The primary follicles in the ovary grow and become a fully mature Graafian follicle.
(b) The endometrium of the uterus is regenerated due to the secretion of LH and FSH from anterior pituitary and ovarian hormone, estrogen.
(c) It least for about 10-14 days.
(iii) Ovulatory Phase (a) Rapid secretion of LH (LH surge) induces rupture of Graafian follicle, thereby leading to ovulation (release of ovum).
(b) It lasts for only about 48 hr.
(iv) Luteal Phase/Secretor Phase (a) In this phase the ruptured follicle changes into corpus luteum in the ovary and it begins to secrete the hormone progesterone.
(b) The endometrium thickens further and their glands secrete a fluid into the uterus.
c) If ovum is not fertilized, the corpus luteum undergoes degeneration and this causes disintegration of the endometrium leading to menstruation.
(d) Oestrogen and progesterone levels rise during this phase. It lasts for only 1 day. (e) During pregnancy all events of the menstrual cycle stop and there is no menstruation. The menstrual cycle permanently stops in females at the age of around 50 years. This is called menopause