The regeneration of tissue shown by an arrow in the picture below starts on which day of menstrual cycle?
A. 5th day.
B. 7th day.
C. 14th day.
D. 28th day.
The tissue shown in the picture above represents Endometrium.
Proliferation phase of endometrium starts from 5th day of menstrual cycle and lasts for 14 days. Proliferative growth of endometrium is influenced by and controlled by estrogen hormone.
3 phases of menstrual cycle are:
- Bleeding phase upto the 4th day
- Proliferative phase 5th to 14th day
- Secretory phase 15th to 28th day
During the bleeding phase: The inner 2/3rd portion of the endometrium which has tortuous arteries gets constricted due to fall in progesterone. The resulting ischemia cause desquamation of inner ⅔ rd of endometrium. The menstrual cast off consist of blood, endometrium, unfertilised ovum, mucus and leukocytes in plenty.
During the secretory phase: It covers the last 14 days of menstrual cycle. This phase is mainly influenced by progesterone from corpus luteum and estrogen. During this phase there is an increase in vascularity of the endometrium and endometrial glands get more spiral and tortuous with glycogen and mucin secretion.