1. Reproductive Physiology 1)Menstrual Cycle 2)Pregnancy 3)Lactation

2. Menstrual Cycle: Generalizations and terms Two main phase: follicular & luteal Pituitary Gland secretes Luteinizing Hormone (LH) Follicle Stimulating Hormone (FSH) Ovary produces follicle containing an egg Follicle then Corpus Luteum secretes Estrogen, Progesterone, Inhibin Uterus prepares for egg fertilization & growth Spike in Progesterone leads to Body Temp spike

3. Menstrual Cycle: Step-by-step FOLLICULAR PHASE 1) Period: old uterine lining sloughed FSH is high > a follicle matures 2) Estrogen gradually increases inhibiting FSH ***ensures only one follicle*** LUTEAL PHASE 3) Estrogen levels peak causing spike in FSH & LH ***ovulation: egg leaves follicle*** Uterine wall thickens **Fertilization can now occur in a ~ 12 hour window** 4) Follicle converted to Corpus Luteum ** Secretes Progesterone & Inhibin ** Prepares Uterus for implantation ***If Fertilization DID NOT OCCUR within 12 hours after 3) then….5 5) Corpus Luteum and Egg dies, Uterine Wall sloughed Estrogen, Progesterone, Inhibin levels drop > FSH increase..back to 1) 1 1 2 1 2 2 3 3 3 3 4 4 4 5 5

4. Pregnancy…..stopping the menstrual cycle! Estradiol ~ Estrogen Corpus Luteum and later Placenta secrete Estrogen & Progesterone This prevents the breakdown of the uterine wall….thus preventing menstruation Estrogen & Progesterone Levels stay elevated due to Human Chorionic Gonadotropin (hCG) Pregnancy tests = hCG tests!

5. Parturition: Labor Mechanism that initiates labor is not well understood: 1)Progestrone & Estrogen drop after labor begins 1)Oxytocin initiates Uterine contractions… but inducing labor with artificial oxytocin doesn’t always work 3)Fetus may secrete a hormone…(CRH, corticotropin releasing hormone, controls adrenal gland) Labor IS well understood: Once labor begins uterus undergoes powerful contractions + Tissue in birth canal softens due to the peptide, RELAXIN = Which eject the baby from uterus and cause delivery

6. Lactation Mammary Gland Myoepitheleal cells Milk secreting cells Smooth Muscle cells Milk Ducts

7. Control of Lactation Suckling Mechanoreceptors Higher Brain Hypothalamus Ant. Pituitary Post. Pituitary PIH Prolactin Oxytocin HAPPY BABY! Milk Secretion Smooth Muscle Contration Oxytocin: Myoepithelial & Duct Muscle Contraction Crying baby PIH = prolactin inhibiting hormone Prolactin: Milk secretion in mammary gland

8. Hope you enjoyed Human Physiology Confocal image of retinal layers