Female Reproductive Physiology

Role of the human female The female human has the following roles in reproduction –Production of the egg –Ovulation –Implantation of the egg –Pregnancy –Birth –lactation

Hypothalamus Anterior Pituitary GnRH Estrogens / Progestins LH and FSH Ovaries

ovary has three zones The functional unit of the ovaries is the single ovarian follicle

Thecal Cell LH cAMP DNA transcription Via PKA cholesterol pregnenolone

Granulosa Cell FSH cAMP DNA transcription Via PKA Enzyme ( aromatase) The granulosa cells do not have the enzymes to convert progesterone into androstenedione so instead must receive androstenedione from the thecal cell. there is an interaction between the thecal and granulosa cells in order to produce estrogens.

LH FSH LDL via cAMP Cholesterol Pregnenolone Androstenedione Thecal Cell Estradiol Granulosa Cell INTO THE BLOOD via cAMP During the Follicular Phase  estradiol.

LH FSH LDL via cAMP Cholesterol Pregnenolone Androstenedione Thecal Cell Estradiol Granulosa Cell INTO THE BLOOD Progesterone Cholesterol Pregnenolone Progesterone via cAMP LH Luteal phase

Negative and Positive Feedback In females, the hypothalamic-pituitary axis is controlled by both negative and positive feedback, depending on the phase of the menstrual cycle

Progesterone Collagenase prostaglandins Hyperemia Swelling of follicle Breakdown of wall Stigma degeneration Rupture and ovulation

Estrogens Estrogen is the word defining the family of sex hormones that include estradiol, estriol and estrone. They are secreted in varying amounts by the ovary but all have similar effects (though different potencies). Estrogens (at Puberty)  Size of Reproductive organs Initiation of Breast development Vaginal Epithelium Infection -resistant Epiphyseal Fusion Histological Changes in Uterine cells

Estrogen(> puberty)  no. and activity Of ciliated cells At oviduct  Protein synthesis Further breast development Ovarian and Menstrual function Subcutaneous Fat deposition

Progestins Two hormones that come under the umbrella of progestins are released by the ovary, progesterone and 17-  -hydroxyprogesterone. The former is secreted in a much greater amount and it is convention to put both under the name progesterone. Progesterone Uterine endometrium Ovulation Alveoli cells Or breast ↓ Uterine excitability During pregnancy

Puberty and Menopause At Puberty: –GnRH activity increases –Eventually leads to ovarian activity –Increased estrogen levels stimulate reproductive organ development. At Menopause –Cessation of the ovarian cycle –Decreased estrogen secretion.

Endocrinology of Pregnancy In order to understand pregnancy you must accept the fetus, placenta and mother all as one unit. This section will discuss the hormone interactions within this unit and the reasons underlying these changes. Human Chorionic Gonadotropin It is produced by the embryo prior to implantation and after implantation is secreted by the syncytiotrophoblast cells in the intravillous space. hCG can be detected in the serum or urine 7-8 days before the expected menses and is the earliest detector of pregnancy. In fact some can now measure hCG levels 2 days after fertilization has taken place.

Corpus Luteum Placenta Progesterone Up to 6 Weeks 6-12 weeks More than 12 weeks

The Placenta The placenta is a specialized organ –Controls exchange between maternal and fetal blood Capillaries from umbilical cord embed in placenta –Called placental villi –Allow for the exchange of blood. allow nutrient uptake, waste elimination, and gas exchange via the mother's blood supply.

Progesterone- Endometrial cells Of uterus And Inhibition of myometrium. Maintains pregnancy Cervical Plug?? Final breast development

Estrogens Prepare body for Parturition( myometrium) Development Of Breast Inhibits Milk production (with progesterone) Initiator of Parturition ???

Human Placental Lactogen (hPL) Growth Hormone Effects ??? On breast Decreases maternal Insulin sensitivity More glucose available For fetus

Example: LMP = 31 May year = 31 May months = 31 February days = 7th February 2012

labor

Diet/Nutrition  demand for carbohydrates, proteins, iron, calcium (Vit D), folate (neural), Vitamin K (clotting factors)

Insulin and glucose levels Must supply adequate levels of glucose to fetus Mother develops hyperglycemia between meals and when sleeping –Increases as pregnancy continues Increase of placental hormones increase insulin resistance –Insulin levels rise

Pituitary- increases in size by 100% predisposing for Sheehan's syndrome

Parturition Role of oxytocin Smooth muscle cell Oxytocin IP 3 & DAGCa 2+ Contraction Delivery of the fetus, occurs approximately 40 weeks after the onset of the last menstrual period. The mechanism of parturition is unclear, although roles for estrogen, progesterone, cortisol, oxytocin, prostaglandins, relaxin, and catecholamines have been proposed.

Initiation of Parturition There is still much controversy and discussion over the mechanisms involved in the initiation of the birthing process. It may be due to a decrease in progesterone levels, an increase in circulating CRH or an increase in estrogen levels, or all three. CRH

Hypothalamus Placenta Posterior Pituitary Uterus Fetus oxytocin pgs Neural reflex oxytocin Contractions of uterus STRESS