What is menstrual cycle ? Describe it in brief.

Explanation

i.Female reproductive system undergoes some changes ( that prepare the uterus for pregnancy ) at puberty and those changes repeat at an interval of every 28-30 days. Scuh repetitive changes are called menstrual cycle.
ii.Menstrual cycle is controlled by four hormones `:` follicle stimulating hormone( FSH ) , luteinizing hormone ( LH ), estrogen and progesterone.
iii. If the ovum is not fertilized , the corpus luteum degeneratesand transforms into corpus albicans. Due to this , secretion of estrogen and progesterone stops completely .In the absence of these two hormones, endometrium starts degenerating.
iv. The tissues of degenerating endometrium along with unfertilized ovum and blood are discarded out through vagina. This bleeding continues approximately for 4-5 days. This is known as menstruation.
v. After the period of menstruation, i.e., on `5^(th)` day of menstrual cycle the endometrium starts to regenerate and one of the several follicles present in the ovary, starts developing along with the oocytes present in it, under the effect of follicle stimulating hormone.
vi. This developing follicle secreted estrogen, under the effect of which endometrium of the utrus starts to develop ( during first cycle ) or regenerate ( during subsequent cycles ) .
vii. After completing its development, follicle ruptures under the effect of luteinizing hormone and oocyte is released . This is called as ovulation. It occurs on `14^(th)` day of menstrual cycle.
viii. Remaining tissue of the ruptured follicle forms corpus luteum and starts secreting progesterone
ix. Under the effect of progesterone and estrogen, endometrical glands are activated and become ready for implanation of the embryo .
x. Unless the oocyt is fertilized and embryo is implanted, menstrual cycle is repeated every month.