Female reproductive

-stimulation of the nipples triggers its release. During labor, oxytocin increases uterine motility, causing contractions in the muscles of the uterus, or womb... -Oxytocin also has social functions. -Produced by the hypothalamus and secreted by the pituitary gland

Oxytocin

Progesterone secreted by placenta and corpus luteum -suppresses premature uterine contractions -prevents menstruation -stimulates proliferation of decidual cells, which nourishes embryo -stimulates development of mammary acini; suppresses FSH and LH secretion

Role and source of Progesterone during menstrual cycle.

are small arteries which temporarily supply blood to the endometrium of the uterus during the luteal phase of the menstrual cycle.. The spiral arteries are converted for uteroplacental blood flow during pregnancy, involving: Loss of smooth muscle & elastic lamina from the vessel wall

Spiral arteries

The stratum functionalis is a thick superficial layer that is sloughed off during menstruation and grows anew during each cycle. It is therefore a temporary tissue with an "unfinished" appearance

Stratum functionalis

erectile tissue around vagina

Vestibular bulbs

Around day 14 of the ovarian cycle, the egg, also called an ovum, or an oocyte, is released from the ovary during ovulation, and it falls into the opening of the uterine tube. This opening (that part right there) has all these tiny fingerlike projections called fimbriae. The fimbriae aren't actually attached to the ovary, so as the egg leaves the ovary, the cilia (those are those really small, tiny, hairlike projections) on the fimbriae have to catch the egg and guide it into the opening.

What moves the oocyte to the uterus

By day 26, involution (shrinkage beginning around day 22) is complete and the corpus luteum has become an inactive bit of scar tissue called corpus albicans

When does the corpus albicans develop

-If the ovum is fertilized, it becomes implanted in the endometrium; implantation usually takes place 3 to 4 days after the Young embryo reaches the uterus 6 or 7 days after the egg was fertilized -Fertilization can only occur if the ovum and sperm are transported simultaneously to the ampullary isthmic junction

Where do fertilization and implantation occur?

The uterine blood supply is particularly important to the menstrual cycle and pregnancy. -a uterine artery arises giving off several branches that penetrate into the myometrium and lead to arcuate arteries. Each arcuate artery travels in a circle around the uterus and anastomoses with the arcuate artery on the other side. -Along its course it gives off several smaller arteries that penetrate the rest of the way through the myometrium, into the endometrium, and give off spiral arteries. The spiral arteries wind tortuously between the endometrial glands towards the surface of the mucosa. They rhythmically constrict and dilate, making the mucosa alternately blanch and flush with blood.

Blood supply to the endometrium

-The vaginal mucosa is a stratified squamous epithelium that structurally resembles the epidermis in many respects, we infer that vaginal and epidermal differentiation have many features in common. -Major function of tissue is protection

Epithelium of vaginal mucosa

FSH stimulates the development of the ovarian follicles, which in turn, secrete estrogens, progesterone, inhibin, and a small amount of androgen. These hormone levels rise gradually from 8 to 12 then spike in teen years. The estrogens are feminizing hormones; most of the visible changes at puberty result from estradiol and androgens.

Follicle Stimulating Hormone

Follicular development. ... At sexual maturity, two hormones, produced by the pituitary gland: (FSH) and (LH) cause these primordial follicles to develop. In each ovarian cycle, about 20 primordial follicles are activated to begin maturation. ( an egg undergoes oogenesis, the follicle around it undergoes folliculogenesis, passing through following stages: primordial follicles, primary follicles, secondary follicles, tertiary follicles, mature follicles)

Follicular development

-stimulates endometrial thickening -(in ovarian cycle--postovulatory phase)- Luteal phase...corpius luteum forms from ruptured follicle under direction of Lutenizing Hormone → ^ progesterone stimulates secretory phase of menstrual cycle (in uterus) -Premenstrual phase- if no pregnancy, corpus luteum → corpus albicans (is an ovarian scar composed of connective tissue that forms after the corpus luteum degenerates) → (decrease progesterone ) → menstruation

Function of corpus luteum

If the leptin level is too low, the hypothalamus does not secrete GnRH. Puberty is therefore delayed in undernourished girls, unusually thick girls, and in other girls with low body fat due to such vigorous and habitual physical activity. If fat stores are adequate then GnRH level rises in late childhood and stimulates the anterior pituitary to secrete follicle stimulating hormone (FSH) and Luteinizing hormone (LH)

Gonadotropin Releasing Hormone

•Hormone cycle produces hierarchy of control hypothalamus→ pituitary→ ovaries → uterus -infant's suckling stimulates sensory receptors in nipple, signaling the hypothalamus & posterior pituitary to release oxytocin

Hypothalamus and female reproductive cycle.

*Perimetrium is external serosa layer* *Myometrium is middle muscular layer* -1 cm thick in nonpregnant uterus -smooth muscle running in all directions -produces labor contractions to expel fetus during delivery *Endometrium* -simple columnar epithelium with thick layer compound tubular glands -stratum functionalis is superficial 1/2 shed with each period -stratum basalis is deeper layer that regenerates a new stratum functionalis with each menstrual cycle

Layers of the uterus

-Estrogens and progesterones regulate FSH and LH secretion through negative feedback inhibition of the anterior pituitary. LH and FSH secretions rise at climacteric and are highly concentrated in the blood -controls the function of the ovaries

Luteinizing Hormone

The ovarian cycle consists of the follicular phase, and ovulation, and luteal phase whereas the uterine cycle is divided into menstruation, proliferative phase, and secretory phase... Under the influence of progesterone, the uterine lining changes to prepare for potential implantation of an embryo to establish pregnancy

How does the ovarian cycle influence the uterine cycle?

Embryonic development of ovary -female germ cells arise from yolk sac of embryo -differentiate into oogonia & multiply in number -transform into primary oocytes(eggs) -- early meiosis I -most degenerate (atresia) by time reach childhood -by puberty 400,000 oocytes remain -Meiosis I is completed on the day of ovulation and produces two daughter cells- a large one called the secondary oocyte and a much smaller one called the first polar body. -The polar body may pointlessly complete meiosis II, but ultimately it, or its daughter cells degenerate **{means of discarding the secondary haploid set of chromosomes} -The secondary oocyte proceeds as far as metaphase II then stops. If it is not fertilized, it dies and never finishes meiosis. -If fertilized it completes meiosis II and casts off a secondary polar body, which disposes of one chromatid from each chromosome. -The chromosome of the larger remaining egg then unite with those of the sperm **note in spermatogenesis a primary spermatocyte gives rise to four equal size sperm. But in Oogenesis a primary oocyte give rise to only one mature egg; the other three daughter cells (polar bodies die)

In oogenesis, what are the end products of meiosis I and meiosis II. What is the ploidy of these cells? When does each occur?

-period lasting 1 or 2 days -it coincides with constriction of the spiral arteries of the endometrium that results from decreasing secretion of estrogen and progesterone. The ischemia results in shrinkage and degeneration of the endometrium

Ischemic phase of endometrial cycle

Low progesterone levels allow FSH levels to stimulate an egg (in a follicle in the ovary) to be matured. This encourages the production of estrogen which repairs the uterus walls and stimulates a surge of LH. This triggers ovulation. After the egg is released from the follicle, it develops into the corpus luteum.

LH and menstrual cycle

Each egg drops develops on its own fluid-filled follicle and is released by ovulation, bursting of the follicle (Ovarian cycle-ovulation) -results from a spike of LH (caused by increase estrogen from follicle) -increase blood flow causes follicle to swell rapidly; collagenase weakens ovarian wall; fluid oozes out with oocyte and is swept up into uterine tube by fimbriae

Ovulation

-a hormone that promotes milk production, in response to the suckling of young after birth, important to reproductive health -produced by the pituitary gland in the brain

Prolactin

Corpus luteum is source of estrogen for first 12 weeks until placenta takes over (progestrone secreted by it) Placenta stores nutrients prior to 3rd trimester: high demand for protein, iron, calcium, and phosphates

Role of the placenta

*Internal genitalia* -duct system consisting of uterine tubes, uterus & vagina *External genitalia* -clitoris, labia minora, and labia majora -occupy the perineum -accessory glands beneath the skin provide lubrication

Secondary sex characteristics

Gonads begin to develop at 6 weeks as gonadal ridges near the primitive kidneys (mesonephros) 2 sets of ducts exist at that time 1. mesonephric ducts develop into male reproductive system (paramesonephric ducts degenerate) 2. paramesonephric ducts (müllerian ducts) develop into female reproductive tract (mesonephric ducts degenerate) SRY gene (Sex-determining Region of Y gene) The female reproductive system develops from the paramesonephric duct because of the absence of testosterone and mullerian-inhibiting factor (MIF). Without testosterone, the mesonephric duct degenerates while the genital tubercle becomes the glans of the clitoris, and the labioscrotal folds develop into the labia majora. Without MIF, the paramesonephric duct develops into the uterine tubes, uterus, and vagina.

What are the derivatives of the mesonephric ducts? What are the derivatives of the paramesonephric ducts? What determines which set develops or degenerates?

-Effects the follicular phase (beginning of menstruation to ovulation- day 1 to day 14) -FSH stimulates continued growth of all follicles in the cohort, but mostly the dominant follicles. FSH stimulates the granulosa cells of the antral follicles to secrete estradiol. In response to estradiol the dominant follicle up-regulates the receptors for FSH, LH, and estradiol, which increases sensitivity to these hormones. At the same time, estradiol inhibits the secretion of gonadotropin-releasing hormone (GnRH) by the hypothalamus. -anterior pituitary gland secretes less and less FSH, but an increasing amount of LH. Most antral follicles suffer from reduction of FSH and degenerate.

What are the effects of FSH and LH on the ovarian cycle?

All 8 week old fetuses have same 3 structures 1) phallus 2) urogenital fold 3)Labioscrotal fold by end of week 9, begin to show sexual differentiation Both genders: -glands begin to develop -urethral groove forms -anus is formed in female: labia minora and labia majora are formed distinctly male or female by end of week 12 -the developing glans become glans of penis and clitoris - both genders contain prepuce and perineal raphe -labia major that women have develops into a scrotum in men

What are the homologies of female and male reproductive systems?