Female Reproductive Cycle

Uterine cycle

endometrium of the uterus prepares for fertilized egg in absensce of zygote, disintegrates and leaves the body.

FSH

stimulates gamete maturation

Is the female orgasm an adaptation? What are the arguments in favor/against?

NO: It's just evidence of our developmental similarities with men (like nipples in men) - evidence: not required for fertilization - sex may be insufficient for orgasm YES: Female orgasm has a fitness enhancing effect,

Oogenesis

process of making the egg

Ovaries

produce estrogen and progesterone

Vagina

receptacle for penis, carries sperm to uterus and fallopian tubes, both canal for babies

Name of only hormone that functions on positive feedback?

Oxytocin

What happen if a women is NOT pregnant

- corpus luteum disintegrates and ovary begins working on a new batch of follicles. - menstruation triggered by drop in estrogen and progesterone because corpus luteum disintegrates

What happens to a woman's body if there is a pregnancy?

- fertilization of egg by sperm penetration signals meiosis 2 to start - corpus luteum will not disintegrate (est/progesterone keep good environment of uterus) - fertilization occurs in fallopian tube

Uterus parts

- Endometrium : inner lining, sheds this layer if not fertilized - Myometrium : middle layer, smooth muscle, assist with labor in pushing the baby out of the uterus. - Perimetrium : outer layer of the uterus

Ovarian cycle

1. Primary follicle contains a primary oocyte and produces estrogen. 2. Secondary follicle. The oocyte is more developed. Estrogen is secreted and a small amount of progesterone. 3. Vesicular follicle produces more estrogen. 4. Day 14 Ovulation occurs when oocyte is expelled (haploid egg cell) 5. Corpus luteum is left and secretes high levels of progesterone and low levels of estrogen. 6. Corpus luteum degenerates if there is no eff implamantation.

Describe the ovarian cycle and include the name of each of the stages and the days on which they occur

Day 1-13 : Follicular phase : FSH from the anterior pituitary stimulates the development of the follicle and estrogen secretion. Day 14: ovulation = release of the oocyte (haploid egg) Day 15-28 : luteal phase: LH from the anterior pituitary gland stimulates the corpus luteum to secrete progesterone. At the end of the lutel phase the corpus luteum degenerates and progesterone secretion drops and menstruation results.

Hormone produced by ovarian follicle and its function in t he ovarian cycle?

ESTROGEN. Which in low levels inhibits the pituitary, high levels stimulates the hypothalamus, promotes building endometrium

Hormone produced by th epituitary and its function in the ovarian cycle?

FSH (follicle stimulating hormone) stimulates the growth of ovarian follicle. LH (lutenizing hormone) stimulates the growth of ovarian follicle and production of secondary oocyte, promotes ovulation, promotes development of corpus luteum and secreion of hormones.

Oviduct

Fallopian tube, fertilization occurs here, ducts or canal which carry ova from ovaries to the uterus

Hormones produced by the pituitary and its function in the ovarian cycle?

GnRH (gonadotropin releasing hormone). It regulates the secretion of LH and FSH by pituitary.

Describe the control of the ovarian cycle by hormones including GnRH, FSH, LH, estrogen and progesterone.

Hormonal messages synchronize ovarian cycle with related events in the uterus that are part of the menstrual cycle. GnRH from the hypothalmus stimulates the anterior pituitary to increase its release of FSH and LH. FSH and LH stimulate the growth of the ovarian follicle. As the follicle grows it secretes more estrogen but it is still at relatively low levels so these low levels exert a negative feedback on the pituitary to keep FSH and LH relatively low in the pre-ovulatory phase. Just before ovulation estrogen peaks which stimulates the hypothalamus to release more GnRH which casues the anterior pituitary to relase a burst of LH and FSH. LH signals enzymes to rupture the follicle and allow ovulation. It also triggers the development of the corpus leuteum from the ruptured follicle and the secretion of estrogen and progesterone from the corpus leuteum. Therefore estrogen and progesterone peak after ovulation. High levels of estrogen and progesterone cause negative feedback on the hypothalamus and the pituitary causing falling levels of FSH and LH. LH drop is followed by degeneration of corpus luteum. The corpus leuteum then stops producing estrogen and progesterone. As levels of these hormones decline the pituitary will start producing FSH and LH again and the cycle will start over.

What is GnRH?

Hormone that stimulates pituitary gland to produce FH and FSH.

What happens as a result of Implantation?

Once implamantaion occurs, the embryo produces HCG. This HCG enters the mothers blood and causes the corpus luteum to secrete high levels of progesterone and estrogen. These hormones maintain the endomentrium so the baby can be nourished by the placenta. After 3 months, the placenta secretes its own progesterone and estrogen and the embryo no longer needs to secrete its own HCG.

Cervix

Openting to uterus, allows passage of sperm and babies

Describe a positive feedback mechanism involving oxytocin.

Stretch receptors in the uterine walls are stiumlated by the baby. These send nerve impulses to the hypothalamus. The hypothalamus produces oxytocin which it sends to the posterior pituitary which secretes it into blood. Oxytocin hormone induces uterine contraction. These contractions stimulates further production of oxytocin which cause even further contractions. It is the only hormone the functions on positive feedback.

Describe the hormonal control of the uterine cycle.

The menstrual cycle is controlled by estrogen and progesterone. Around day 5 of the cycle the endometrium thickens due to rising levels of estrogen and then progesterone. Estrogen is initially secreted by the maturing follicle and then the corpus luteum secretes estrogen and progesterone. When the levels of this hormone drops off due to the degeneration of the corpus luteum, the endometrium is sloughed off and then the menstrual period starts on day 1 of the new cycle.

Describe the functions of estrogen

The primary female sex hormone. They promote the development of primary and secondary sex characteristics in females. They are also involved in regulation of the menstrual cycle.

Meiosis in ovaries produces eggs cells

about 1,000,000 cells begins meiosis before birth meiosis stops in prophase I about 400,000 oocytes remains in puberty each month, a few oocytes proceed to metaphase II hormones triggers release of an oocyte (ovulation)

Vulva

external sex organ of women

Clitoris

most sensitive, arousal and sexual excitement

urethra

passage for urine