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Menstrual cycle

 

Menstrual cycle 

The periodic ( monthly) discharge of blood, mucus and worn out tissues of uterine wall during reproductive cycle ( until menopause) of a woman is called menstruation. 

It is a 28 day cycle,  which starts at puberty between the age of 12-13 and continues up to 40-50 age until menopause.

Menopause is the period(between 40-50year age)during which a woman is unable to reproduce.  It is characterize by the stop of menstrual flow. 

Menstruation is divided in to four phases

1. Menstrual phase 

2. Post Menstrual phase or proliferative phase 

3. Ovulation phase 

4. Post ovulatory or premenstrual phase


1. Menstrual phase

This is a five day long phase( 1st-5th day) .
This phase starts when the egg is not fertilized by the sperm and the female sex hermone lable decreases.
Menstrual phase is characterize by the discharge of blood with sloughed tissue from endometrial lining. 

2. Proliferative phase or proliferative phase

This is the phase between the menstruation and ovulation.
Proliferative phase starts on the 6th day after menstruation phase stops and last till 13th day. 
During this time the repair and growth ( proliferation) of endometrial lining occurs by the influence of oestrogen hermone which is secreted by follicular cells. 
Oestrogen hermone level is maximum in this phase. 



3. Ovulation phase 

In this phase the ovulation occurs in 14th day of the cycle. 
The LH hermone from anterior pituitary controls the rupture of graafian follicle to release an ovum. 

4. Post ovulatory or premenstrual phase 

 This phase is also known as secretory phase, which is 15 to 28 days long phase. 
In this phase the endometrium thickens, due to increase in the progesterone level, the uterine glands are mature to produce a thick mucoid secretion , due to which this phase is called secretory phase.

If fertilization occurs, 
 The corpous leuteum is maintained by the HCG ( human chorionic gonadotropin) hermone .
The corpous leuteum and placenta secretes progesterone and oestrogen hermone to support pregnancy and development of breast for lactation. 

If fertilization doesn't occurs, 
The corpous leuteum degenerate and   level of progesterone and  oestrogen hermone falls, which allows the discharge of endometrial wall followed by another menstrual phase. 


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Location: India

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