Female Reproductive System: Functions, Cycle Phases, and Hormonal Regulation

What are the four primary functions of the female reproductive system?

Producing ova, receiving sperm to facilitate fertilization, housing and nourishing the developing embryo, and lactating to feed the young.

What is the primary function of the oviducts (fallopian tubes)?

They collect secondary oocytes from the ovary and serve as the site of fertilization.

What are the two layers of the uterus and their primary roles?

The myometrium is a thick wall of smooth muscle; the endometrium lines the lumen and thickens monthly to prepare for potential embryo implantation.

What is the primary cause of cervical cancer?

Over 99% of cases are caused by the Human Papillomavirus (HPV).

At what stage of meiosis are primary oocytes arrested at birth?

They are arrested in prophase I.

What is the result of unequal cytokinesis during the first meiotic division of a primary oocyte?

It results in one polar body (n) and one secondary oocyte (n).

At what stage of meiosis is the secondary oocyte arrested prior to ovulation?

It is arrested at metaphase II.

What triggers a secondary oocyte to complete meiosis II?

The entry of a sperm cell.

What are the three phases of the ovarian cycle?

The follicular phase (days 1-13), ovulation (day 14), and the luteal phase (days 15-28).

What are the three phases of the uterine cycle?

The menstrual flow phase (days 1-5), the proliferative phase (days 6-13), and the secretory phase (days 15-28).

Which two hormones are primarily secreted by the corpus luteum?

Progesterone and estradiol.

What is the primary role of progesterone in the menstrual cycle?

It completes the preparation of the endometrium for pregnancy and stimulates endometrial glands to secrete nutrient-rich fluid.

How does the hypothalamus initiate the ovarian cycle?

It secretes GnRH, which stimulates the anterior pituitary to release FSH and LH.

What mechanism causes the LH surge during the late follicular phase?

High levels of estradiol secreted by the maturing follicle exert positive feedback on the hypothalamus and anterior pituitary.

When does ovulation typically occur in relation to the LH surge?

Approximately one day after the LH surge.

What happens to the remaining follicle tissue after ovulation?

LH stimulates it to become the corpus luteum, which acts as a temporary endocrine gland.

What causes the corpus luteum to disintegrate in the late luteal phase?

Low levels of FSH and LH.

What hormonal change triggers the menstrual flow phase?

The disintegration of the corpus luteum leads to a drop in estradiol and progesterone, causing the endometrial lining to shed.

How is the proliferative phase of the uterine cycle coordinated with the ovarian cycle?

It is coordinated with the follicular phase, where ovarian hormones stimulate the thickening of the endometrium.

What is the function of the cervix?

It closes the uterus and separates it from the vagina.

What happens to primary oocytes between birth and sexual maturity?

The number of primary oocytes decreases from about 1-2 million at birth to about 200,000 by sexual maturity.

Why does the endometrium disintegrate if fertilization does not occur?

The breakdown of the corpus luteum causes a drop in hormones, leading to the constriction of endometrial arteries and loss of circulation to the lining.

What is the role of cilia in the oviducts?

They help move the secondary oocyte toward the uterus.