Physiology & The Menstrual Cycle

David A. Grainger, MD, MPH

July 8, 2015

Disclosures

• I have no disclosures.

Learning Objective

• To understand the menstrual cycle

12 51

20 weeksBirth

menopausemenarche

6-7 million

1-2 million500,000

0

Medial Basal Hypothalamus

Pituitary

Ovary

Medial Basal Hypothalamus

Pituitary

Ovary

TSHPRLACTHGHFSHLH

OxytocinVasopressin

Median eminence

Arcuate nucleus

GnRH

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E2 LH

FSH

Follicular Phase LH Surge Luteal PhaseProliferative Phase Secretory Phase

LH

FSH

Theca

Granulosa

Oocyte

Cumulus

Medial Basal Hypothalamus

Pituitary

Ovary

TSHPRLACTHGHFSHLH

OxytocinVasopressin

Median eminence

Arcuate nucleus

Sex steroids (progesterone, androgens, estrogens)Inhibin

GnRH

LH Surge:

1. Induces Ovulation1. PG production2. Proteolytic Enzyme

induction2. Shift from Estrogen to

Progesterone production3. Resumption of Meiosis

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E2

P4

LH

FSH

Follicular Phase LH Surge Luteal PhaseProliferative Phase Secretory Phase

40 hoursovulation