Q.38 - Biology

Question

Describe the events in the ovarian cycle leading up to ovulation. 

Step-by-Step Solution

Answer

The ovarian cycle consists of three phases: follicular (preovulatory) phase, ovulation, and luteal (postovulatory) phase.

Step 1. Introduction

Ovarian cycle

• cycle of preparation of egg for ovulation and the conversion of the follicle to the corpus luteum.

Ovulation

• Release of the egg by the most mature follicle.

Step 2. Explanation

Low levels of progesterone allow the hypothalamus to send GnRH to the anterior pituitary and cause the release of FSH and LH. 

FSH stimulates follicles on the ovary to grow and prepare the eggs for ovulation. 

As the follicles increase in size, they begin to release estrogen and a low level of progesterone into the blood. 

The level of estrogen rises to a peak, causing a spike in the concentration of LH. This causes the most mature follicle to rupture and ovulation occurs.