Menstruation and Reproductive Hormones

Page 2: Male Reproductive System

  • Testosterone Hormone

    • Produced in interstitial cells of testes

    • Small amount from adrenal glands in both sexes

  • Effects of Testosterone:

    • Maintains accessory glands and male reproductive organs

    • Promotes bone and muscle growth

    • Influences libido (sexual desire)

    • Results in facial hair, increased muscle mass, and larger body size

Page 3: Female Hormones and Cycles

  • Cycles:

    • Ovarian cycle and uterine cycle controlled by hormonal changes

    • Both cycles must synchronize for proper reproductive function

Page 4: Ovarian Cycle

  • Involves changes in ovarian follicles (structures around developing oocytes)

  • At puberty, about 400,000 primordial follicles remain

  • Others degenerate in a process called atresia

  • Each month, Follicle Stimulating Hormone (FSH) stimulates development of several follicles

Page 5: Ovarian Cycle Phases

  • Follicular Phase:

    • Egg follicle prepares to release an egg; new endometrium layer begins to grow

    • Last 5 days of this phase plus ovulation day are the most fertile

  • Luteal Phase:

    • Begins on ovulation day when egg is released

Page 6: Phases of the Ovarian Cycle

  • Hormone Levels:

    • Gonadotrophic hormones influence

  • Phases:

    • Follicular Phase

    • Ovulation

    • Luteal Phase

  • Hormonal Effects:

    • Estrogen and progesterone levels fluctuate throughout the cycle

Page 7: Hormonal Fluctuations and Temperature Changes

  • Monthly hormonal fluctuations affect body temperature

  • Luteal Phase: High progesterone levels

  • Follicular Phase: Higher estrogen causes basal body temperature to be ~0.3ºC lower

Page 8: Key Hormones in Reproductive Cycle

  1. Gonadotropin-Releasing Hormone (GnRH):

    • Origin: Hypothalamus

    • Function: Stimulates release of FSH and LH from pituitary gland

  2. Follicle-Stimulating Hormone (FSH):

    • Origin: Pituitary gland

    • Function: Stimulates ovarian follicle development

  3. Luteinizing Hormone (LH):

    • Origin: Pituitary gland

    • Function: Triggers ovulation; supports corpus luteum development

Page 9: Female Hormones

  1. Estrogen:

    • Origin: Primarily from ovaries

    • Function: Crucial for developing female reproductive tissues; regulates menstrual cycle

  2. Progesterone:

    • Origin: Secreted by corpus luteum

    • Function: Prepares uterus for pregnancy; maintains uterine lining

Page 10: Uterine Cycle Overview

  • Menstrual cycle begins at puberty (menarche around age 11-12)

  • Average Length: 28 days (range: 21-35 days)

  • Continues until menopause (age 45-55)

  • Can be interrupted by illness, stress, starvation, or pregnancy

Page 11: Phases of the Uterine Cycle

  • Menstrual Phase:

    • First phase; flow of menses indicates no pregnancy

    • Interval from ovulation to menstruation is always 14 days; pre-ovulatory phase varies

    • Normal menstrual blood loss: 25-65 ml

Page 12: Proliferative Phase

  • Lasts the first 2 weeks; dominated by estrogen

  • Endometrium thickens as ovulation approaches

  • Surge in LH at 14 days triggers ovulation; follicle ruptures releasing an egg

Page 13: Continued Proliferative Phase

  • Ruptured follicle develops into corpus luteum under LH

  • Corpus luteum produces progesterone; if egg is fertilized, it sustains pregnancy until placenta takes over

  • If not fertilized, corpus luteum atrophies 3 days before menstrual phase

Page 14: Secretory Phase

  • Corpus luteum produces progesterone, making endometrium receptive for implantation

  • Increases blood supply to the uterus; decreases contractions

  • If egg not fertilized, estrogen sharply decreases

Page 15: Menstrual Phase

  • Ischemic endometrium sheds, including blood, mucus, and cellular debris

  • Duration: 3-5 days; varies among females

  • Symptoms: Hormonal, emotional, and physical changes, including breast tenderness, cramps, fatigue, and mood swings

Page 16: Phases of the Ovarian Cycle

  • Hormonal levels and physiological changes throughout the ovarian cycle influencing the uterine cycle

  • Diagrams illustrating hormone fluctuations and corresponding body temperature changes

Page 17: History Questions

  • Assessing menstrual health:

    • Questions on excessive bleeding, typical cycle length, menstrual flow, pain levels

    • Inquiries on bleeding between periods and tiredness

Page 18: Terminology

  • Mittelschmerz: Abdominal pain during ovulation affecting ~20% of women

  • Menarche: Onset of first menses

  • Amenorrhea: Absence of menses; most commonly due to pregnancy, but can arise from exercise, stress, or anorexia nervosa

Page 19: Fertilization

  • Occurs when sperm penetrates egg; fertilization typically happens in uterine tube

  • Egg viability: 12-24 hours post-release; degeneration starts after this time

  • Egg's journey to uterine cavity takes 3-4 days

Page 20: Menopause

  • Cessation of the menstrual cycle, commonly between ages 45-55

  • Slow decrease over 1-3 years before stopping completely

  • Decrease in estrogen leads to susceptibility to osteoporosis, mood swings, and urinary issues

  • Common symptoms: Hot flashes, night sweats, and replacement therapy for symptom management.