Female Reproductive System Physiology

Study Notes

Hormonal Regulation and Follicle Development

Mature follicles secrete estrogen, which inhibits Follicle Stimulating Hormone (FSH) secretion, leading to degeneration of other primary follicles.
Estrogen reaches the uterus via blood circulation, stimulating proliferative changes in the endometrium.
Typically, only one follicle reaches maturity during each menstrual cycle, resulting in the release of a single oocyte while others degenerate.

Ovulation Process

Defined as the release of the secondary oocyte from the Graafian follicle.
The secondary oocyte pauses in metaphase of meiosis II about three hours before ovulation.
Occurs approximately 14 days into the menstrual cycle, marking the middle of the ovarian cycle.
Follicle Stimulating Hormone (FSH) and Luteinizing Hormone (LH) spur rapid growth of the secondary follicle, increasing follicular fluid volume and pressure in the follicle's antrum.
The Graafian follicle bulges and ruptures to release the ovum into the peritoneal cavity, where it is captured by the fimbriae of the fallopian tube.

Circumstances Affecting Ovulation

Ovulation does not happen during pregnancy and occurs minimally during lactation.
Body temperature slightly increases during ovulation.
Some women may experience mild discomfort known as mid-cycle pain.
Contraceptives contain estrogen and progesterone to inhibit ovulation, while agents that stimulate gonadotropin are utilized to treat sterility.

Ischemic Phase

The ischemic period occurs during the last 2-3 days of the secretory phase, coinciding with the degeneration of the corpus luteum.
There is a sudden drop in estrogen and progesterone levels due to corpus luteum degeneration.

Menstrual Cycle Overview

The menstrual cycle consists of the ovarian cycle and the uterine cycle.
Menstruation typically lasts around 3-5 days in a normal 28-day cycle.
During menstruation, only the functional layer of the endometrium sheds, while the basal layer remains intact.

Quiz Highlighted Statements

True: Menstruation generally lasts 3-5 days in a 28-day cycle.
False: The entire endometrium is not shed; only the functional layer is lost.
True: The absence of menstruation does not always indicate an active pregnancy.

Hormone Production Locations

Luteinizing Hormone (LH) and Follicle Stimulating Hormone (FSH) are produced in the anterior pituitary gland.

Clinical Note

Endometriosis is mentioned as a clinical consideration related to menstrual cycle abnormalities.

Description

This quiz covers the role of mature follicles in secreting estrogen, which inhibits FSH secretion, leads to endometrial changes, and results in ovulation of a single oocyte. It also discusses the process of ovulation and the release of the secondary oocyte from the Graafian follicle.