Summary of CICLO MENSTRUAL. OVULACIÓN. HORMONAS. ¡Explicación INTEGRADA! Fácil de entender. Ciclo Ovárico.

Summary of the Video: "CICLO MENSTRUAL. OVULACIÓN. HORMONAS. ¡Explicación INTEGRADA! Fácil de entender. Ciclo Ovárico."

This video provides a comprehensive and integrated explanation of the Menstrual Cycle, focusing on both the ovarian and endometrial (uterine) cycles, and the hormonal regulation that governs these processes. The explanation is detailed, emphasizing the hormonal interplay, follicular development, ovulation, and changes in the endometrium, aiming to make the complex physiology easier to understand.

Main Ideas and Concepts

  1. Overview of the Menstrual Cycle
    • The Menstrual Cycle consists of two interconnected cycles:
      • Ovarian Cycle: changes in the ovary (follicular growth, ovulation, Corpus Luteum formation).
      • Endometrial (uterine) cycle: changes in the uterine lining (menstruation, proliferation, secretion).
    • Both cycles are regulated by the neuroendocrine system involving the hypothalamus, pituitary gland, and ovary.
  2. Ovarian Cycle Phases
    • Follicular Phase (Day 1 to Day 13):
      • About 150 primary follicles begin development; 5-20 progress to secondary follicles.
      • Only one follicle matures into a Graafian (mature) follicle; others undergo atresia.
      • Follicle-stimulating hormone (FSH) stimulates follicular growth and granulosa cell proliferation.
      • Increasing granulosa cells raise estrogen production (estradiol), leading to the estrogen peak.
      • Estrogen exerts positive feedback on the hypothalamus and pituitary ~72 hours before ovulation.
      • This triggers a surge in luteinizing hormone (LH), known as the LH peak, occurring 24-48 hours before ovulation, which induces ovulation (~day 14).
    • Ovulation (Around Day 14):
      • The mature follicle releases the egg.
      • The ruptured follicle transforms into the Corpus Luteum.
    • Luteal Phase (Day 15 to Day 28):
      • Corpus Luteum cells (theca and granulosa lutein cells) produce progesterone and estrogen.
      • LH primarily stimulates the Corpus Luteum, increasing progesterone production.
      • Progesterone levels rise above estrogen levels, marking this phase as progesterone-dominant.
      • Progesterone prepares the endometrium for potential implantation.
      • If fertilization does not occur, Corpus Luteum degenerates, progesterone and LH levels fall, triggering menstruation.
      • If fertilization occurs, the embryo produces Human Chorionic Gonadotropin (hCG), which maintains Corpus Luteum function and progesterone production, preventing menstruation.
  3. Endometrial (Uterine) Cycle Phases
    • Menstrual Phase (Day 1-4):
      • Functional layer of the endometrium (compact and spongy layers) is shed.
      • Basal layer remains intact.
    • Proliferative Phase (Day 5-14):
      • Estrogen stimulates mitosis and regeneration of the endometrium from the basal layer.
      • Glands are straight; spiral arteries are not yet fully developed.
    • Secretory Phase (Day 15-28):
      • Progesterone dominance causes endometrial thickening.
      • Glands become tortuous and secrete glycogen-rich substances.
      • Spiral arteries elongate and become tortuous to support possible embryo implantation.
      • If progesterone falls (no fertilization), the functional layer detaches, starting menstruation.
      • If fertilization occurs, progesterone remains high, supporting decidualization and pregnancy maintenance.
  4. Hormonal Dynamics and Feedback
    • FSH stimulates follicular growth; estrogen rises during Follicular Phase.
    • Estrogen exerts positive feedback on LH secretion to trigger ovulation.
    • LH surge causes ovulation and Corpus Luteum formation.
    • Corpus Luteum produces progesterone and estrogen, but progesterone predominates in Luteal Phase.
    • Progesterone supports endometrial secretory changes.
    • Decline in progesterone and LH leads to menstruation.
    • hCG from embryo maintains Corpus Luteum and progesterone if fertilization occurs.
    • FSH levels rise modestly at mid-cycle but are overshadowed by the LH surge.
  5. Key Points to Remember
    • The Menstrual Cycle is divided into ovarian and uterine cycles, each with three phases.
    • The Follicular Phase and proliferative phase are estrogen-dominant.
    • The Luteal Phase and secretory phase are progesterone-dominant.
    • The LH surge is the key hormonal event triggering ovulation.
    • Progesterone prepares the endometrium for implantation and supports early pregnancy.

Category

Educational

Summarize another video

Video