Ovulation and Corpus Luteum Formation

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the function of the corpus luteum after ovulation?

To stimulate the release of FSH

To stimulate the growth of another follicle

To cause menstruation

To produce estrogen and progesterone (correct)

What happens to the granulosa cells and theca interna after ovulation?

They degenerate and are replaced by fibroblasts

They become smaller and produce estrogen

They stop producing hormones and undergo apoptosis

They increase in size and become specialized in producing progesterone and estrogen (correct)

What is the role of LH in the corpus luteum?

To stimulate the growth of follicles

To cause the corpus luteum to degenerate

To stimulate the production of FSH

To promote the production of estrogen and progesterone (correct)

What happens to the corpus luteum if pregnancy does not occur?

It degenerates, and the remnants are phagocytosed by macrophages Signup and view all the answers

What is the role of hCG in the corpus luteum of pregnancy?

To prevent the drop in progesterone levels Signup and view all the answers

What is the corpus luteum of menstruation?

A structure that forms after ovulation and only lasts one menstrual cycle Signup and view all the answers

What happens to the corpus luteum of pregnancy after 4-5 months?

It is replaced by the placenta, which produces enough progesterone to maintain the uterine mucosa Signup and view all the answers

What is corpus albicans?

A scar of dense connective tissue that forms after the corpus luteum has degenerated Signup and view all the answers

What stimulates the release of follicle-stimulating hormone (FSH) from the pituitary gland?

Gonadotropin-releasing hormone (GnRH) from the hypothalamus Signup and view all the answers

What is the effect of estrogen on the release of GnRH and LH?

It increases the release of GnRH and LH Signup and view all the answers

What is the function of inhibin in the menstrual cycle?

It reinforces the negative feedback of estrogen and progesterone on the hypothalamus and anterior pituitary Signup and view all the answers

What happens to the oocyte after the LH surge?

It completes meiosis I and is released from the ovary Signup and view all the answers

What is the fate of the corpus luteum in the absence of pregnancy?

It undergoes regression and apoptosis without further LH stimulation Signup and view all the answers

What is the effect of the decrease in progesterone on the uterus?

It causes menstruation, the shedding of the uterine mucosa Signup and view all the answers

What is the result of the decrease in estrogen levels after menstruation?

It leads to an increase in FSH secretion, stimulating new follicle growth Signup and view all the answers

What is the fate of the regressing corpus luteum?

It is phagocytosed by macrophages and replaced by a scar of dense connective tissue Signup and view all the answers

Study Notes

Corpus Luteum Formation

After ovulation, granulosa cells and theca interna form a temporary endocrine gland called corpus luteum.
Corpus luteum is influenced by LH, which causes granulosa cells to increase in size and become granulosa lutein cells, while theca interna cells become smaller theca lutein cells.

Hormone Production

Under LH influence, granulosa lutein cells and theca lutein cells produce estrogen and progesterone for 10-12 days.
If pregnancy does not occur, hormone production stops, and LH levels decrease, leading to apoptosis of the cells.

Menstrual Cycle

The decrease in hormone production leads to menstruation.
FSH secretion increases, and the growth of a new group of follicles begins, starting the next menstrual cycle.
The corpus luteum that lasts only one menstrual cycle is called the corpus luteum of menstruation.

Corpus Luteum Regression

After the corpus luteum degenerates, remnants are phagocytosed by macrophages, and fibroblasts invade the area, producing a scar called corpus albicans.

Pregnancy

If pregnancy occurs, the hormone hCG is produced by the trophoblast cells of the implanted embryo, maintaining progesterone levels.
The corpus luteum of pregnancy grows larger over time and is maintained by hCG for 4-5 months.
Eventually, the placenta takes over progesterone production, and the corpus luteum of pregnancy is replaced by corpus albicans.

Follicular Development and Hormonal Regulation

Follicular development depends on follicle-stimulating hormone (FSH) from the pituitary gland, which is stimulated by gonadotropin-releasing hormone (GnRH) from the hypothalamus.
The dominant follicle secretes estrogen, which increases the release of GnRH and leads to a surge in luteinizing hormone (LH) from the pituitary gland.

Hormonal Mechanisms

Inhibin, a hormone produced by granulosa and luteal cells, reinforces the negative feedback of estrogen and progesterone on the hypothalamus and anterior pituitary.
Estrogen and progesterone have a negative feedback mechanism on the hypothalamus and anterior pituitary.

Ovulation and Oocyte Release

The LH surge causes meiosis I to be completed, resulting in a primary oocyte and first polar body.
Granulosa cells are stimulated to produce more follicular fluid, and the ovarian wall weakens.
Smooth muscle contractions begin in the theca externa, leading to increased pressure and wall weakening, causing the follicle to rupture at the stigma.
The oocyte, along with its surrounding corona radiata and follicular fluid, is expelled and adheres loosely to the ovary surface.
The oocyte must be fertilized within about 24 hours or it begins to degenerate.

Hormonal Function and Fate of the Corpus Luteum

In the absence of pregnancy, the corpus luteum secretes progesterone for 10-12 days after ovulation due to the LH surge.
Without further LH stimulation, the corpus luteum cells stop producing steroids and undergo apoptosis.
The decrease in progesterone leads to menstruation, the shedding of the uterine mucosa.
Lowered estrogen levels lead to increased FSH secretion, stimulating new follicle growth and starting the next menstrual cycle.
The regressing corpus luteum is phagocytosed by macrophages and replaced by a scar of dense connective tissue, the corpus albicans.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

This quiz covers the process of ovulation, the formation of the corpus luteum, and the changes that occur in granulosa cells and theca interna under the influence of LH. It explains how these cells produce progesterone and estrogen.