histology of the female reproductive tract

Question 1

Organs of the female reproductive system

Answer 1

Ovary (The female Sex gland), the oviduct (fallopian tube), uterus, vagina, external genitalia, mammary glands, Function of the female reproductivesystem: produce the female gametes, produce teh hormones estradiol and progesterone, receive male gametes during sex

Question 2

function related to childbearing

Answer 2

provides a suitable environment for conception, provides a suitable environment for implantation and embryo development

Provides a suitable environment for implantation and embryo development

Provides a mechanism for birthing, provides nourishment for the infant

Question 3

Coverings of the ovary

Answer 3

Each ovary is covered by germinal epithelim (modified peritoneum), tunica albuginea (collagenous connective tissue capsule)

Question 4

Ovarian structure

Answer 4

Cortex- contains ovarian follicles surrounded by stromal interstitial cells and loose CT

Medulla- contains larger blood and lymphatic vessels and nerves surrounded by CT

Question 5

Ovarian follicles Germinal cells

Answer 5

Migration to ovarian cortex 6th wk of development, multiplication by mitosis, some oogonia develop the potential to become mature female gametes, encapsulation by follicular cells, first stage of meiotic division arrested

At birth, no further follicular development until sexual maturity

Sexual maturity–> secretion of pituitary gonadotrophins FSH and LH, some primordial follicles develop towards maturity with each ovarian cycle, increasing secretion of oestrogen progresively inhibits secretion first meiotic division completed, second meiotic division commences, high levels of oestrogen inhibit FSH secretion and promotes secretion promotes secretion of LH

Question 6

Ovarian follicles Germinal cells ovulation , fertilization, and implantation

Answer 6

Progesterone secretion by corpus luteum maintained by LH, inhibition of LH secretion by progesterone, Fertilization, and implantation (corpus luteum of pregnancy maintained by HcG secreted by developing empryo

Question 7

OOgenesis/oogonium

Answer 7

primordial germ cells develop during the first weeks of embryogenesis and under go several mitotic divisions, by the 6th week of gestation they migrate to the germinal ridges to populate the developing ovarian cortex and are referred to as oogonia, continue to undergo mitossis until about the 5th fetal month

About 5-7 million but only 1 mil become surrounded by follicular cells and survive around the time of birth

The oogonia that survive are called primary oocytes and these cells enter prophase 1 of meiosis 1
The remaining oogoina under go atresia the degenerate and die

Question 8

Primordial follicle

Answer 8

Primordial follicle is composed of a primary oocyte surrounded by a single layer of flattened follicular cells, thare are separated from the ovarian stroma by a basement membrane

Question 9

primary follicle

Answer 9

unilaminar, usually multilaminar (granulosa) cells, zona pellucida separates the oocyte from the surrounding follicular cells

Stromal cells begin to organize around the multilaminar primary follicle forming an inner theca interna composed of a vascularized layer, and an outher theca externa composed mostly of fibrous connective tissue

Question 10

Secondary follicle

Answer 10

Difference between secondary and primary is the appearance of a follicular antrum within the granulosa layer, this gap contains fluid called liquor folliculi
The follicle is surrounded by the theca interna that produce androstenedion which enters the granulosa cells and is converted by aromatase int the estrogen Estradiol

Question 11

Tertiary (Graafian follicle)

Answer 11

the tertiary / graffian follicle is characterized by a large follicular antrum, it is surrounded by the zona pellucida and a layer of several cell known as Corona radiata

Question 12

Ovum

Answer 12

Gonadotropin surge induces entry of the primary oocyte into meiosis resulting in the formation of the 2 daughter cells, the secondary oocyte and the 1st polar body

The secondary oocyte enters meiosis 2 that gets arrested at metaphase 2 the secondary oocyte is haploid

The oocyte enlarges du to an increase in cytplasmic volume, the surface of the ovary where the follicle is pressing degenerates forming an opening between the peritoneal cavity and the antrum of the graffian follicle, the secondary oocyte completes meiosis 2 but only if fertilized , resulting in 2 haploid cells the ovuum and the second polar body

Question 13

Fetal development

Answer 13

during fetal development meiosis 1 begins, after puberty primary oocytes complete meiosis 1 which produces a secondary oocyte and a first polar body that may or may not divide again, the secondary oocyte begins meiosis 2, a secondary oocyte (and first polar body) is ovulated, after fertilization, meiosis 2 resumes, the oocyte splits into an ovum and a second polar body

The nuclei of the sperm cell and th ovum unite forming a diploid 2n zygote

Question 14

Corpus luteum

Answer 14

it is the endocrine remains of the collapsed follicle, the center contains the remains of the blood clot that formed after ovulation, surrounding the clot are luteal cells and are luteal cells and on the outside are theca lutein cells, Granulosa lutea cells are temporary endocrine glands and produce progesterone and inhibin as well as convert androgens (produced by the theca lutein cells) into estrogens

If pregnancy occurs hCG secreted by the placenta, maintains the corpus luteum for 3 months

Question 15

Corpus albicans

Answer 15

the corpus luteum has 10-12 day lifespan, the secretory cells of the corpus luteum degenerate and are phagocytized, it becomes filled with fibrous scar tissue

Question 16

Atretic follicle

Answer 16

degeneration of follicle (atresia) can occur at any stage of development, the granulosa cells undergo apoptosis and consequently the oocyte degenerates, the basement that separated the oocyte from granulosa cells often thickens to become the glassy membrane, fibrous material replases the granulosa cells

Question 17

hormonal control of the ovaries

Answer 17

The hypothalamus releases GnRH, which control the release of the anterior pituitary hormone (FSH and LH)
FSH and LH stimulate follicle growth and thecal cells-mediated secretion of estrogens

Estrogen has a transient negative feedback effect on the anterior pituitary , inhibiting output of FSH and LH

As levels of estrogen increase they result in a burst of LH and to a lesser extent FSH, this sudden burst of LH and FSH stimulates completion of meiosis as far as metaphase 2 and it also stimulates completion of meisosis as far as metaphase 2 and it also stimulates the synthesis of enzymes involved in bulging of the ovarian wall, LH promotes the transformation of the ruptured Graafian follicle into the corpus luteum to secrete progesterone and estrogen, Progesterone and estrogen have a neg feedback effect on the anterior pituitary and inhibit FSH and LH production, this prevents development of new follicles

Question 18

oviducts

Answer 18

Fallopian and uterine tubes
A Pair of muscular walled tubular structures (12 cm each with an open end and an attached end to the uterus, the oviducts are covered by the broad ligament

The wall is dominated by an elaborate mucosa that is thrown into numerous branched folds, surrounded by smooth muscle, as the tube moves away from the ovary and toward the uterus these folds become smaller and the smooth muscle dominates, it is lined with epithelium the ciliated cells that move the ovum away from the ovary and toward the uterus and the non ciliated secreoty peg cells that release a secretion that lubricates the tube and provides nourishement and protection to the traveling ovum

Question 19

Infundibulum, fimbriae, ampulla, and isthmus

Answer 19

at the open end is the infundibulum, which is fringed with projection called fimbriae, these fibriae help to capture the secondary oocyte, the expanded ampulla is where fertilizationg usually takes place, the isthmus is the narrowed portion between the ampulla and the uterus

Question 20

Tubal ligation

Answer 20

tube tied is a type of surgery that closes the fallopian tubes, which connect the ovaries to the uterus, its generally considered to be a permanent form of birth control (can sometimes be reversed, but not always)

Question 21

Uterus

Answer 21

A single pear shaped structure- body, fundus, and cervix
The uterine wall of the body and teh fundus is composed of the permetrium

The myometrium consists of 3 layers of smooth muscle, inner circular, outer longitudinal, and middle oblique

It expands during pregnancy and protects and expels the fetus

The endometrium consists of 2 additional layers: stratum functionalis is a thick superficial layer that is sloughed during menstruation, stratum basalis is a deep narrow layer that facilitates the regeneration of the functionalis

Question 22

Endometrial blood supplu

Answer 22

straight basal arteris- supply basal zone , spiral arteries, supply basal and functional zones

Question 23

Uterine fibroids (myoma)

Answer 23

Benign tumors of smooth muscle cells, the most common benign tumors in women and the leading indication for hysterectomy in the US, 60% af am women, 80% by age 50 leyomyoma

Question 24

Cervix

Answer 24

The upperr cervix (endocervix) is lined bya simple columnar that contains mucous secreting cells

In contrast, the lower cervix (ectocervix) is lined by a strartified squamous epithelium that protects against the vaginal environment

The transition point between these 2 epithelia is known as the transformation zone, the underlying layers of the cervix are composed primarily of collagenous aand elastic conntective tissue rather than smooth muscle fibers

Question 25

Vagina

Answer 25

Its a muscular tube lined with non keratinized stratified squamous epithelium, underneath the epithelium is a layer of lamina propria which is rich in elastic fibers, and does not have any glands, under the lamina propria is a layer of smooth muscle which has an inner circular and outer longitudinal layer, finally there is an adventitial layer which merges with that of the bladder (anterioraly) and rectum- posteriorly, the vagina is lubricated by cervical mucus and mucus from gland in the labia minora

Question 26

cyclic changes of the endometrium during the menstrual cycle

Answer 26

The early proliferative phase begins at the end of menstrual flow, the uterine glands in this phase are sparse and small, and the epithelial cells develop microvilli and cilia under the influence of estrogen

The late proliferative phase reveals an increased thickness of the stratum functionalis and the glands are more coiled and densely packed

Question 27

Secretory and menstrual phase

Answer 27

the secretory phase of the uterine cycle begins at ovulation in this phase the glands become even more complexly coiled and the endometrial lining reaches its maximal thickness, whereas the stratum basalis and myometrium remain relatively unchanged

If fertilized does not occur, the corpus luteum degenerates, the uterine lining does not receive progesterone causing the spiral arteries to constrict and the endometrial tissue to become ischemic, this causes cell death and the sloughing of the stratum functionalis during the menstrual phase

Question 28

Placenta

Answer 28

if fertilization and implantation do occur the placenta develops at the site of implantation, serves as an endocrine organ secreting a number of hormones which include hCG and progesterone, the human placenta is composed of both maternal and fetal tissues,

Decidua basalis is derived from the maternal endometrial lining, chorionic villi emerge from the chorion that surrounds the embryo, the villi invade deciduas blood filled lacunae to facilitate exchange between the fetus and mother, nutrients gases, waste products and macromolecules are transferred between the maternal blood in the lucunae and the tiny vessels in villi