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Menstrual cycle review

Phases, timeline, and hormones of menstrual cycle.
This article provides a review of:
  • events of the menstrual cycle, and
  • timeline and hormone levels involved.

Key terms

TermMeaning
menstruationperiodic shedding of endometrial lining through vagina
menarchefirst occurrence of menstruation, marking start of fertility
menopauseending of menstrual cycle, marking end of fertility
ovulationperiodic release of egg from ovary
FSHfollicle stimulating hormone
LHluteinizing hormone
corpus luteumremains of follicle that released egg

What is the menstrual cycle?

Why do female human beings get a 'period' every month? In fact, why is it called a period? Does this happen only to humans?
All sexually mature female mammals undergo a process that allows them to reproduce. This is known as the menstrual cycle in primate mammals like humans.
Menarche, or first menstrual bleeding (first period), is considered to be the onset of puberty in human females, roughly between the ages of 1115. Menopause is the stopping, or end of the menstrual cycle, roughly around the ages of 5255. Reproductive ability begins and ends with these two milestones.
Test your understanding
Anu is 54 years old. She begins to have hot flashes, irregular periods, and difficulty falling asleep. She consults a doctor, and is told she is undergoing menopause.
Which of the following statements explain what this means for Anu?
Choose 1 answer:

Menstrual cycle at a glance

The image below illustrates the timeline of the menstrual cycle, along with the hormonal changes that accompany it.
EventCharacteristicsTimeline
Menstrual phaseShedding of endometrial lining through menstruation.Starts on day 1, lasts up to 57 days.
Follicular/proliferative phaseDevelopment of follicles, thickening of endometrium begins.Follows menstrual phase, ends with ovulation.
OvulationSurge in LH, rupture of Graafian follicle to release egg.Mid cycle, roughly day 14.
Luteal/secretoryMaintenance of endometrium by corpus luteum.Follows ovulation, goes on for roughly 14 days until day 28.
Test your understanding
It's day 12 of Babli's cycle.
Which of the following statements is likely to be true?
Choose 1 answer:

Test your understanding
The endometrial wall thickens as the menstrual cycle progresses, and is eventually broken down if pregnancy does not occur.
Identify the statement that matches the state of endometrial development with the correct timeline.
Choose 1 answer:

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