Menstrual Cycle                    

What is menstrual cycle?

       Female reproductive system undergoes some changes at puberty and those changes repeat at interval of every  28 - 30 days. These repetative changes are called as Menstrual cycle.

Puberty is marked by thr onset of Menstrual cycle. While puberty is marked by the concept of Menarche and Menopause.

Menarche : Starting point of menstrual cycle. It's starts approx at the age of 10 - 14 yrs.

Menopause : End point of the menstrual cycle. It's ends approx at the age of 45 - 50 yrs.

Menstrual cycle is a natural process. It is controlled by Four hormones, namely

• Follicle stimulating hormone.  [ FSH ]
• Luteinizing hormone.   [ LH ]
• Estrogen.
• Progestrone.

Follicle stimulating hormone and luteinizing hormone is situated in Brain (Pitutary gland)

Estrogen and progestrone is situated in Ovary.

1 - 5 DAY's

In the first 1 - 5 days ... endometrium will break down, and will lead to bleeding. The released blood will come out through vagina. At the time of bleeding, pituitary gland will produce FSH (1 - 5 days ). 

• One of the several follicles in ovary starts to develop.
• This developing follicle will secrete estrogen.( after 5 days )
• This eastrogen acts on the endometrium
• Endometrium of the uterus starts to regenerate.

End of 5 days.

At 14th Day

• The developing follicle completes its development.
• On the 14 day, pituitary will produce LH.
• Follicle will burst under the offect of LH, and the oocyte is released. 

This release of oocyte is known as Ovulation.

After 14th Day

• Remaining tissue of the burst follicle forms the Corpus Luteum.
• Corpus Luteum starts to secrete Progesterone.
• It will act on endometrium.
• Endometrial gland secrete their secretion.
• Such a Endometrium is ready for implantation of embryo.
• If the oocyte is Not Fertilized within 24 hrs, Corpus lutenum becomes inactive and transform into Corpus Albicans.
• Secretion of eastrogen and progesterone stops completely.

Endometrium starts to degenerate in absence of these two hormones.

This is accompanied with continuous bleeding known as Menstruation.

Blood consists of tissues and unfertilized ovum.

If the Embryo is implanted repetition of this cycle is temporarily stopped till the parturation and thereafter period of breast freeding.