CICLO MENSTRUAL (FISIOLOGIA DE GUYTON) - MENSTRUAÇÃO - FISIOLOGIA HUMANA - OVULAÇÃO

Summary

In this video, Cleverson Deuveque provides a simple and clear explanation of the menstrual cycle, focusing on the hormonal interactions involved. He describes the key roles of hormones like FSH, LH, estrogen, and progesterone, explaining their impact on the endometrium and ovulation. Cleverson breaks down each phase, from menstruation through to ovulation and the formation of the corpus luteum. The video also covers the feedback mechanisms that regulate hormone levels, highlighting the role of contraception in preventing ovulation. The explanation aims to make the complex physiology of the menstrual cycle accessible to viewers.

Takeaways

• 😀 The menstrual cycle begins on the first day of menstruation, which is the shedding of the endometrium from the uterus.
• 😀 The endometrium is regenerated after menstruation, and the process is regulated by the endocrine system, specifically hormones like FSH, LH, estrogen, and progesterone.
• 😀 FSH, released by the pituitary gland, stimulates the ovary to produce estrogen, which promotes the formation of a new endometrium in the uterus.
• 😀 Estrogen also triggers a surge in LH, which leads to ovulation and the release of the secondary oocyte.
• 😀 After ovulation, the ruptured follicle transforms into the corpus luteum, which secretes progesterone to maintain the endometrium.
• 😀 If fertilization does not occur, progesterone levels drop, causing the endometrium to shed, leading to menstruation again.
• 😀 The menstrual cycle is tightly regulated by negative feedback mechanisms: Estrogen inhibits FSH production, while progesterone inhibits LH production.
• 😀 The role of progesterone is crucial in sustaining the endometrium to support potential pregnancy; if there is no fertilization, progesterone levels fall and menstruation resumes.
• 😀 The contraceptive pill works by keeping estrogen and progesterone levels elevated, which prevents the release of FSH and LH, effectively stopping ovulation.
• 😀 In the case of fertilization, human chorionic gonadotropin (hCG) is released, signaling the corpus luteum to continue producing progesterone and support the pregnancy.

Q & A

What is the first day of the menstrual cycle defined by?

The first day of the menstrual cycle is defined by the onset of menstruation, where the shedding of the endometrium occurs and blood is released through the female reproductive system.

What is the role of FSH in the menstrual cycle?

FSH (Follicle Stimulating Hormone) is released by the pituitary gland and stimulates the ovaries to release estrogen, which helps in the proliferation of the endometrium after menstruation.

What happens when the estrogen levels peak?

When estrogen levels peak, it triggers a surge in LH (Luteinizing Hormone), which is crucial for ovulation. This leads to the release of the secondary oocyte from the ovary.

What is the function of progesterone during the menstrual cycle?

Progesterone is responsible for maintaining the endometrium after ovulation, ensuring it remains intact to support a potential pregnancy. If fertilization does not occur, progesterone levels drop, leading to the shedding of the endometrium and the start of menstruation.

What happens to the follicle after ovulation?

After ovulation, the ruptured follicle transforms into the corpus luteum, which secretes progesterone to maintain the endometrium.

How does the feedback mechanism regulate the menstrual cycle?

The feedback mechanism in the menstrual cycle works through negative feedback. For example, estrogen inhibits the release of FSH, and progesterone inhibits the release of LH, ensuring that the cycle progresses correctly and ovulation occurs.

What is the role of LH in the menstrual cycle?

LH (Luteinizing Hormone) plays a key role in triggering ovulation by causing the release of the secondary oocyte. Additionally, LH stimulates the corpus luteum to secrete progesterone.

What happens if fertilization does not occur?

If fertilization does not occur, the corpus luteum degenerates, leading to a decrease in progesterone levels. This causes the endometrium to shed, resulting in menstruation.

How do oral contraceptives prevent ovulation?

Oral contraceptives maintain elevated levels of estrogen and progesterone, which suppress the release of FSH and LH, preventing ovulation and thus reducing the chances of pregnancy.

What role does hCG play in pregnancy detection?

Human chorionic gonadotropin (hCG) is released after fertilization and implantation of the embryo. It signals the corpus luteum to continue producing progesterone, maintaining the endometrium for embryo implantation, which is also used in pregnancy tests to detect early pregnancy.