Draw a neat labelled diagram of T.S. of ovary and describe various phases of menstural cycle.

Explanation

Phases of Menstrual Cycle :
1. Menstrual Phase : Bleeding phase, Day : ` 1^("th") "to" 4^("th")` day.
If ovum is not fertilized, the lining of the uterus degenerates and menstruation begins. Menstrual cycle consists fo secretion from endometrial glands, cell debris, blood and unfertilized egg. During menstrual flow 35 to 45 ml of blood is lost.
2. Proliferative phase or follicular phase: Day : 5 to 13 day.
During this phase, primordial follicle of the ovary develops into Grannfian follicle .
Oestrogen secreted by follicular cells of ovary stimulates endometrial glands. This causes repair of endometrium. The endomtrial cellss proliferate and grow to thickness of about 3 mm to 5 mm.
3. Ovulatory phase : Day : 14 day .
It is the process in which there is rupture of Graafian follicle with discharge of ovum into abdominal cavity. It is under the influence of luteinzing hormone.
4. Luteal phase/Secrotory phase : Day : 15 to 28 day.
After ovulation , ruptured follicle develops into a yellow body called corpus lutem. Corpus luteum acts as temporary endocrine gland which secretes progesterone. It is also called pregnancy hormone.