Female reproductive anatomy Ovaries produce estrogen, progesterone, and are site of oogenesis Estrogen: maintenance of the female tracts, 2 o sex characteristics, ova maturation and release

Oogonia divide mitotically Meiosis I produces a primary oocyte (diploid), surrounded by follicle cells These oocytes develop into secondary oocytes on a cyclical basis Oogenesis overview

Follicular phase - first half of cycle when follicles mature and are ovulated Luteal phase - second half of cycle when uterus is prepared for implantation Ovarian cycle

Primary follicle oocyte Follicle cells Looking within the ovary…follicular phase FSH and LH levels are increasing

Follicle cells secrete estrogen Dividing follicular cells Thecal cells Primary oocyte Looking within the ovary…follicular phase

antrum Antrum collects fluid with estrogen Estrogen inhibits FSH and LH, so FSH Looking within the ovary…follicular phase

Thecal cells Granulosa cells Antrum primary oocyte Late follicular phase High estrogen levels promote LH secretion w/ positive feedback loop

Late follicular phase Mature follicle Antrum Oocyte finishes meiosis I it now is a 2 o oocyte

Follicle remains secondary oocyte Egg is flushed out Pop! Ovulation!

corpus luteum Luteal phase Corpus luteum secretes progesterone and estrogen

Estrogen and progesterone Estrogen initiates preparation of endo- and myometrium, ‘prime’ uterus for progesterone (follicular phase) Progesterone endometrium vascularization, glycogen, decrease contractions (luteal phase) Progesterone inhibits LH and FSH (this is how birth control pills work)

If the corpus luteum degenerates, progesterone drops and menstruation occurs Changes in endometrium Degenerating corpus luteum

Fertilization normally occurs within a day of ovulation Contractions of the myometrium help some sperm reach the oviduct But if there are sperm around… acrosome in action

Embryo Trophoblast Implants the embryo Blastocyst Cleavage Fertilization Ovulation Implantation Embryo forms before reaching the uterus

Blastocyst secretes chorionic gonadotropin Endometrium has glycogen, and becomes more vascularized from progesterone 40% of blastocysts never implant Settling into the uterus…

Trophoblast enzymes digest proteins of the endometrium. This carves a hole for implantation. Settling into the uterus… Endometrium Trophoblast Embryo Endometrium

Embryo Eventually forms chorion

Placenta = chorion from embryo and uterine lining from mother. These tissues interlock like ‘fingers’ Projections of chorion have capillaries to form placental villi. They extend into the mother’s blood. Placenta development

Gasses, wastes, nutrients diffuse bw capillaries of mother and fetus Drugs, pollutants, chemicals also diffuse Placenta development mother’s blood Placental villus Amniotic sac Chorion

Human chorionic gonadotropin (hCG) Estrogen Progesterone FertilizationDelivery

Questions  Is reproduction different for a female with a single ovary?  Abortion via chemical means  Does scoliosis affect the ability to carry/deliver a child?  Does the fact that female genitals are inside the body allow for wider range of lower body movement? Athletes want to know

Relaxin from placenta softens the cervix and pelvis Uterus has mild contractions. Baby’s head is down in pelvis High levels of estrogen make the uterus more sensitive to oxytocin. Progesterone levels drop Getting ready for birth....

Stretching the cervix causes more oxytocin to be released Oxytocin induces stronger contractions Positive feedback with oxytocin

Lactation

 If students are interested, I will go over the extra credit information at the end of this class.  I will need to hear some feedback via to know if students are interested in this so I’ll prepare extra slides…thanks