Question

TRUE OR FALSE.

1A. The spike of luteinizing hormone (LH) in the middle of the menstrual cycle causes the follicle to rupture and the egg to burst out of the follicle.

1B. In a 28 day menstrual cycle, ovulation occurs around day: 14

1C. This hormone, Gonadotrophin releasing hormone (GnRH) stimulates primary oocytes to begin maturing and stimulates follicles to begin producing estrogen.

1D. The increased levels of estrogen at the middle of the menstrual cycle, which stimulate LH secretion, is an example of BOTH negative and positive feedback loops.

Answer 1

1A) True

Increased levels of estrogens cause LH surge which cause ovulation i.e the follicle rupture and the egg bursts out of the follicle.

1B) True

A menstrual cycle consists of 2 phases: follicular phase and luteal phase.... Normally the luteal phase is fixed and it is 14 days.so in a 28 day cycle ovulation occurs at 14 days after which the luteal phase begins.

1C) False.

It is FSH which stimulates the oocytes and the production of estrogen.GnRH acts on pituitary to stimulate the production of FSH and LH.

1D) False.

It is an example of positive feedback mechanism only.

Elevated levels of estrogens, during luteal phase, inhibit LH secretion by negative feedback mechanism.