In menstural cycle , why low concentration of estrogen provides negative feedback to the LH hormone and hiigh concentration of estrogen provides positive feedback to LH??

Q. High concentration of LH and estrogen lead to:

Q. Menstrual cycle is controlled by -
A. Estrogen and progesterone of ovary
B. FSH of pituitary
C. FSH and LH of pituitary
D. Oxytocin hormone

Q. What is the source of increase in concentration of estrogen in the proliferative phase of menstrual cycle?

Q. You have learnt that a characteristic feature of endocrine system is the presence of feedback loops. By this what is meant if hormone A stimulates gland ‘X’ to secrete hormone B, the production of ‘A’ could be modified when the level of B changes in our blood.

An example is the relation between hormones LH and estrogen (E2). An old woman exhibits the following features. High levels of LH in blood but low levels of E2 in the blood. Another woman exhibits high level of LH in blood and also high level of E2 in the blood. Where is the defect in both these women? Provide suitable diagram to support this answer.