Menstrual Cycle Quiz

Reproductive Physiology LOs

• Oogenesis, folliculogenesis, and the ovarian cycle are described
• A typical ovarian cycle is detailed along with how folliculogenesis spans multiple ovarian cycles
• Ovulation and the role of luteinizing hormone (LH) in the process are defined
• The endocrine regulation of oogenesis, folliculogenesis, and the ovarian cycle is explained
• The uterine (menstrual) cycle is discussed

Uterine (Menstrual) Cycle

• The phases of the uterine cycle (menstrual) are named and the anatomical changes in the uterine wall during each phase are described
• The correlation between the uterine and ovarian cycles is detailed
• The average human cycle is about 28 days (length of lunar month)
• The range is approximately 25-30 days (follicular phase of the ovarian cycle)

Human Menstrual Cycle

• The hypothalamic-pituitary-ovarian axis tightly regulates the human menstrual cycle
• Gonadotropins released from the pituitary (LH, FSH) induce regular changes in the ovaries and uterine endometrium, which creates ovarian and uterine cycles

Menstrual Cycle (Ovarian + Uterine Cycle)

• The menstrual (destructive) phase occurs from days 1-5, involving menstruation and the sloughing off of the endometrium
• The follicular (proliferative/estrogenic) phase spans from days 5-14, beginning after the end of menses and extending to ovulation, where ovaries secrete estrogen as follicles mature, and the uterine lining grows thicker, preparing for fertilization
• The luteal phase occurs from days 14-28, starting from ovulation and continuing to the next menstruation, involving secretion of estrogen and progesterone by the corpus luteum, allowing the uterine lining to enter the secretory phase, which becomes the ideal place for egg implantation

Ovarian Cycle

• The follicular phase involves the maturation of ovarian follicles to prepare one for ovulation, and follicles begin secreting estrogen
• During the late follicular phase, the dominant follicle (Graafian follicle) becomes ready for ovulation, and estrogen levels peak
• The luteal phase follows ovulation, and the corpus luteum forms and secretes estrogen and progesterone

Uterine Cycle Details

• The menstrual phase (menses) involves the sloughing off of the endometrium due to the drop in progesterone and estrogen levels
• The proliferative phase involves the rebuilding and thickening of the endometrial lining under the influence of estrogen
• The secretory phase involves the endometrium becoming thick and spongy under the influence of progesterone, making it ideal for a fertilized egg to grow

Role of Hormones in the Menstrual Cycle

• Hypothalamic Hormone (Gonadotropin Releasing Hormone): Stimulates the secretion of follicle-stimulating hormone (FSH) and luteinizing hormone (LH)
• Gonadotropin Hormones (FSH): Stimulates immature follicles to grow and produce a mature egg
  • (LH): Allows for the release of the egg from the ovary (ovulation)
• Sex Hormones (Estrogen and Progesterone): Provide negative feedback to prevent extra eggs being produced, remain high during pregnancy; if no fertilization occurs level drops triggering menstruation

Menstrual Cycle Variations

• Predicting ovulation precisely in advance can be challenging, as ovulation typically occurs about 14 days before the next menses
• Physical cues such as mittelschmerz (pain from follicle rupture), changes in body temperature (increase of 0.5-1 degree during luteal phase) and changes in cervical mucus (pre-ovulatory thick and post-ovulatory thin) can be used as indicators for ovulation
• Lab tests such as LH levels can also help in predicting ovulation

Contraceptives

• Combination pills (estrogen and progesterone) or mini pills (progesterone only) stop ovulation by slowly releasing progestin into the body
• Progestin provides negative feedback at the hypothalamus, thus decreasing GnRH which results in less FSH and LH production
• Estrogen decreases follicular development and thickens cervical mucus to make implantation more difficult

Premenstrual Syndrome (PMS)

• PMS is related to the withdrawal of estrogen and progesterone; symptoms can include physical and psychological changes occurring 3-10 days before menstruation
• Treatments and causes are highlighted in the text

Menstrual Variations (Dysmenorrhea and Amenorrhea)

• Dysmenorrhea, or painful menstruation, involves uterine cramps, ischemia, and increased levels of prostaglandin
• Common treatments for dysmenorrhea include NSAIDs and exercise
• Amenorrhea, or the absence of menstruation, is categorized as primary (no menstruation by age 15) or secondary (3-6 months without menstruation)
• Factors such as pregnancy, menopause, diet, and exercise may play a role
• Oligomenorrhea, or skipped menstrual cycles, is highlighted along with risk factors

Test your knowledge on the menstrual cycle! This quiz covers key concepts including the phases of the menstrual and ovarian cycle, hormonal effects, and common menstrual disorders. Perfect for anyone looking to deepen their understanding of female reproductive health.