Female Reproductive System 1

Female reproductive system

consists of the paired ovaries and uterine tubes (or oviducts/fallopian tubes), the uterus, the vagina, and the external genitalia

menarche

Beginning at ______, when the first menses occurs, the reproductive system undergoes monthly changes in structure and function, under the control of neurohormonal mechanisms

menopause

represents a variably timed period during which the cyclic changes become irregular and eventually disappear.

Simple cuboidal epithelium or germinal epithelium

Each ovary is covered by ________

Tunical albuginea

Overlying the capsule is ________

Cortex; ovarian follicles

Most of the ovary consists of the _____, a region of highly cellular connective tissue stroma containing many _____ that vary greatly in size after menarche

Medulla

The most internal part of the ovary encompasses loose connective tissue and blood vessels entering the organ through the hilum from the mesenteries suspending the ovary

primordial germ cells or oocytes

In the first month of embryonic life, a population of gamete stem cells, referred to as _______ or gonocytes, migrates from the yolk sac to the two developing gonads.

oogonia

As the ovaries develop in chromosomal females, gonocytes there differentiate as progenitor cells called _______

Atresia

After this point the number of oogonia depends on three ongoing activities: continued mitosis, the onset of meiosis, and an apoptotic process in the female gametes called _______.

primary oocytes

Most of these cells undergo apoptotic cell death, but others complete synapsis, genetic recombination, and arrest in meiotic prophase I and the gametes at this point is referred to as _____

follicular cells

Primary oocytes is surrounded by flattened, supportive _____ in a non-growing primordial follicle, the total number of which constitutes the “ovarian reserve.

ovarian follicle

consists of one oocyte surrounded by one or more layers of epithelial cells within a basal lamina

primordial follicles

Follicles that develop during fetal life—_______—do so without gonadotrophin input, form mainly in the superficial ovarian cortex, and consist of primary oocytes each enveloped by a single layer of squamous follicular cells form mainly in the superficial ovarian cortex

FSH

Prompted by ____, an oocyte grows rapidly during the first part of follicular development, reaching a diameter of about 120 μm

cortical granules

During oocyte differentiation, formation of small secretory granules called ______ containing various proteases happens. These become densely distributed just inside the oocyte’s plasma membrane and undergo exocytosis during fertilization.

unilaminar primary follicle

Follicular cells divide and enlarge, making a simple cuboidal epithelium around the growing oocyte in the expanding _____________

granulosa; granulosa cells; multilaminar primary follicle

When follicular proliferation continues, creating a stratified epithelium, the ______, in which abundant gap junctions allow cellular coordination and transfer of materials. This time, the follicular cells are now termed as ______ in a still avascular ________ surrounded by a basement membrane.

zona pellucida

Between the rapidly growing oocyte and the first layer of granulosa cells of the growing primary follicle, proteins secreted from both cell types assemble into a layer of extracellular matrix 5–10 μm thick known as the ______

ZP1, ZP2, ZP3

Zona pellucida glycoproteins _______, all synthesized in the oocyte, represent components of sperm-binding receptors that attach specific proteins on capacitated sperm and begin acrosomal activation, allowing sperm to progress through this ECM.

Polycystic ovary syndrome (PCOS)

Characterized by enlarged ovaries with numerous cysts and an anovulatory state (with no follicles completing maturation successfully).

Follicular theca

Stromal cells immediately outside each growing primary follicle differentiate to form the vascularized ________ which subsequently develops further as two distinct tissues around the follicle.

Theca Interna; luteinizing hormone; androstenedione

A well-vascularized endocrine tissue, the _______, consists of fibroblasts, capillaries, and typical steroid-producing cells which in response to ________ secrete ________.

estradiol

Androstenedione, when diffused into the follicle through the basement membrane to the granulosa cells, where the enzyme aromatase converts it to ______, an FSH-dependent activity

theca externa

A more fibrous______ with fibroblasts, capillaries, and smooth muscle merges gradually with the surrounding stroma.

follicular fluid or liquor folliculi; antrum; secondary or antral follicles

Within such follicles, small spaces gradually appear among the granulosa layers as the cells secrete ______ which then accumulates, the spaces enlarge and gradually coalesce, and the granulosa cells reorganize themselves around a larger cavity called the ________ producing follicles now called _______

cumulus oophorus

As the antral follicle develops, the oocyte and granulosa cells immediately around it form a small hillock, the ________ protruding into the largest antrum

corona radiata

The granulosa cells tightly adhering to the oocyte through the zona pellucida comprise the _______ and accompany the oocyte when it leaves the ovary at ovulation

mature or Graafian follicle

Each month typically only one antral follicle that began developing 2 or 3 months earlier becomes __________ with a single large antrum that rapidly accumulates more follicular fluid and expands to a diameter of 2 cm.

Atresia; atretic

Follicular cells and oocytes undergo apoptosis and removal by phagocytic cells. Follicles at any stage of development, including antral follicles nearing maturity, may become _____

dominant follicle

During a typical menstrual cycle, one antral follicle becomes the ________, developing farther than the others, reaching the most developed stage and undergoing ovulation, while most of the other primary and antral follicles undergo atresia.

Ovulation

The hormone-stimulated process by which the oocyte undergoes release from the ovary.

14th day

Ovulation normally occurs midway through the menstrual cycle, that is, around the _____ of a typical 28-day cycle.

stigma

Shortly before ovulation, he mature dominant follicle bulges against the ovary’s tunica albuginea sufficiently to block local blood flow and produce an elevated, ischemic area, the ______, below the germinal epithelium

secondary oocyte; first polar body

The chromosomes undergo equal division between two daughter cells, but one of these retains almost all the cytoplasm. That cell now becomes a _______ and the other cell becomes the _______, a very small nonviable structure with a nucleus but hardly any cytoplasm.

secondary oocyte; metaphase

Immediately after expulsion of the first polar body, the nucleus of the _______ begins the second meiotic division but arrests again at ______ and never completes meiosis unless it gets fertilized

Oogenesis; prophase I

______ begins in the female fetus, with primary oocytes arresting at ______ in primordial follicles, which remain inactive during childhood.

gonadotropin-releasing hormone (GnRH)

As mentioned before, follicular development depends on FSH from pituitary gonadotrophs, whose secretion is stimulated by ______ from the hypothalamus.

inhibin

Note that negative feedback of estrogen and progesterone on the hypothalamus and anterior pituitary is reinforced by a polypeptide hormone, _____, also produced by granulosa and luteal cells.

primary oocyte

Meiosis I is completed by the ______, yielding a secondary oocyte and the first short-lived polar body

prostaglandins

Granulosa cells are stimulated to produce more follicular fluid containing _____, proteoglycans, and proteases that break down the surrounding blood-follicle barrier

hyaluronan

The granulosa cells in the cumulus oophorus also release _____, which increases fluid viscosity and swells to greatly increase the extracellular volume within this structure, loosening its outer cells, and dissociating it from the follicle wall.

plasminogen

At the stigma, the ovarian wall weakens as activated ______ (plasmin) from broken capillaries degrades collagen in the tunica albuginea and surface epithelium.

theca externa

Smooth muscle contractions begin in the ______, triggered by prostaglandins diffusing from follicular fluid.

corpus luteum

After ovulation cells of the ovulated follicle’s granulosa and theca interna reorganize to form a larger temporary endocrine gland, the _________, in the ovarian cortex

cholesterol

The granulosa is now invaded by capillaries, which bring in _____, the major precursor of steroid hormones

Stigma scar

the capsule closes over the rupture formed during ovulation.

Large cells (Granulosa Lutein Cells)

Secrete progesterone and convert androgens formed by theca lutein cells into estrogen.

Theca Lutein Cells

More peripherally located cells derived from theca interna cells producing androstenedione a.k.a precursor to synthesis of androgens and estrogens

Smaller cells

Secrete androgens, progesterone and some estrogen

granulosa lutein cells

Granulosa cells increase in size to 20–35 μm in diameter, without dividing, and eventually comprise about 80% of the corpus luteum, mostly centrally located. Now called _______, they still release some inhibin while losing many features of protein synthesis and greatly expanding the SER, the site of progesterone synthesis and aromatase conversion of androstenedione into estrogens.

theca lutein cells; androstenedione

The former theca interna comprises the rest of the corpus luteum as _______. Half the size of the granulosa lutein cells, the theca lutein cells synthesize ______ and typically aggregate in the peripheral folds of the now well-vascularized corpus luteum.

corpus luteum of menstruation

The short-term corpus luteum that persists for only part of one menstrual cycle represents a _________

corpus albicans

Remnants from its regression are removed by macrophages, and fibroblasts invade the area and produce a scar of dense connective tissue called a _________

human chorionic gonadotropin (hCG)

To prevent the drop in circulating progesterone, trophoblast cells outside the implanting 7-day embryo begin secreting a glycoprotein called ___________________ functionally similar to LH.

Uterine tubes or oviducts

Paired ducts that catch the ovulated secondary oocyte, nourish both the oocyte and sperm, provide the microenvironment for fertilization, and transport the embryo undergoing cleavage to the uterus.

infundibulum; fimbriae

____ is a funnel-shaped segment with its opening fringed with fingerlike extensions called ______ (L., fringes) next to the ovary;

ampulla

the longest and expanded region where fertilization normally occurs

isthmus

a narrow portion adjoining the uterus

uterine or intramural part

passes through the wall of the uterus and opens into the interior of that organ.

ampulla

The numerous branching, longitudinal folds of the mucosa develop most prominently in the ______

intramural portion

The mucosal folds become smaller in the regions closer to the uterus and disappear in the ______ of the tube

Ciliated cells

Along its entire length, the mucosa consists of simple columnar epithelium on a lamina propria of loose connective tissue containing ______ which functions for ciliary movements sweep fluid toward the uterus

Secretory peg cells; glycoproteins

nonciliated and often darker staining, often with an apical bulge into the lumen, which secrete _______ of a nutritive mucus film that covers the epithelium.

follicular growth phase

Triggered primarily by estrogens, the cilia elongate and both cell types undergo hypertrophy during the ______

Late luteal phase

When do the different epithelium cells lose its cilia or undergo atrophy?

capacitation factors

The secretion covering the mucosa has nutritive and protective functions for both the oocyte and the sperm, including ______ that activate sperm and make those cells able to fertilize an oocyte.

Fertilization

the union of a secondary oocyte and a spermatozoan which normally occurs in the tube’s ampulla, a region usually reached by only a few hundred of the millions of ejaculated sperm.

hyaluronidase

Upon contact with cells of the corona radiata sperm release _____ by exocytosis, which allows sperm to move more easily between the coronal cells to the zona pellucida.

ZP3, acrosomal reaction, acrosin

At the zona pellucida, specific enzymes on the sperm surface interact with the multimeric sperm-binding receptors, in which the _______ component then activates the __________. This causes rapid exocytosis of the main acrosomal protease _____ and other hydrolytic enzymes at multiple sites across the broad acrosomal surface, leading to localized degradation of the zona pellucida.

cortical reaction, ZP3, perivitelline barrier; polyspermic fertilization

This then triggers exocytosis of proteases from the oocyte’s cortical granules, the ______, which quickly spreads like a wave across the entire surface of the oocyte. Proteases released from the granules very rapidly hydrolyze _____ and other spermbinding components throughout the zona pellucida, converting it to the impenetrable ______ that constitutes a permanent block to _________.

Ca+2; pronucleus; protamines; zygote

The rise of _______ in the secondary oocyte causes its nucleus to immediately complete meiosis II, producing a second polar body and the female pronucleus of the haploid ovum. Leaving the flagellum and midpiece behind, the haploid nucleus of the single penetrating sperm head is drawn into the ovum toward its _______, losing ______, loosening its chromatin compaction, and becoming the male pronucleus. Fusion of the two pronuclei yields a new diploid cell, the ____ (Gr. zygotos, yoked together)

Uterus

develops as a medial, pear-shaped organ with thick, muscular walls.

uterine body; fundus

The two uterine tubes enter its largest part, the ______ and the curved, superior area between the tubes represents the ____.

isthmus; cervix

The uterus narrows in the _____and ends in a lower cylindrical structure, the _____.

cervical canal; internal os; external os

The lumen of the cervix, the ________, has constricted openings at each end: the ______ (L. os, mouth) opens to the lumen of the isthmus and the ______ to the vagina

perimetrium

An outer connective tissue layer, the ______, continuous with the ligaments, which is adventitial in some areas, but largely a serosa covered by mesothelium

myometrium

A thick middle tunic of highly vascularized smooth muscle, the ________

endometrium

A mucosa, the ______, lined by simple columnar epithelium

Functional layer of the uterus

the part that changes histologically and functionally depending on estrogen levels

Stratum basalis

bordering the myometrium (M), contains the basal ends of the uterine glands (G) and many small arteries (A) embedded in a distinctive connective tissue stroma with many fibroblasts, ground substance, and primarily fine type III collagen, but no adipocytes

FSH; LH; estrogens; progesterone

The cyclic development of ovarian follicles and the corpus luteum, controlled by the pituitary gonadotropins ____ and _____, lead to cyclic shifts in the levels of the major ovarian hormones: steroidal _____ and ______.

functional layer

After ovulation the corpus luteum forms and produces both progesterone and estrogens, which together promote growth and development of the endometrial ______

myometrium

the thickest uterine tunic, shows bundles of smooth muscle fibers separated by connective tissue containing venous plexuses and lymphatics

hyperplasia

During pregnancy the myometrium goes through a period of extensive growth involving both ______ (increasing the number of smooth muscle cells), cell hypertrophy, and increased collagen production by the muscle cells, all of which strengthen the uterine wall

parturition

This well-developed uterine myometrium contracts very forcefully during _______ to expel the infant through the cervix

Endometrium; type III collagen

The lamina propria or stroma of _______ consists primarily of bundled ______ with abundant fibroblasts and ground substance.

simple columnar epithelial lining; uterine glands

Its _______has both ciliated and secretory cells, and the latter line the numerous tubular ________, which penetrate the full thickness of the endometrium

basal layer

adjacent to the myometrium has a more highly cellular lamina propria and contains the deep basal ends of the uterine glands

superficial functional layer

has a spongier lamina propria, richer in ground substance, and includes most of the length of the glands, as well as the surface epithelium

arcuate arteries; radial arteries

______ in the myometrium send two sets of smaller ______ into the basal layer of the endometrium

Spiral arteries

Uniquely sensitive to progesterone, growing rapidly in a spiral fashion as the functional layer thickens under the influence of that luteal steroid and providing blood to a microvasculature, which includes many lacunae lined by thin endothelium. This blood supply brings oxygen and nutrients to cells of the functional layer and to an embryo implanting itself into that tissue.

Straight arteries

Blood supply for the basal layer

vascular lacunae

Spiral arteries branch into numerous arterioles supplying a rich, superficial capillary bed that includes many dilated, thin-walled _______ drained by venules.

Endometriosis

a disorder with pelvic pain due to endometrial tissue growing on the ovaries, oviducts, or elsewhere.

pituitary gonadotropins

From puberty until menopause, ______ produce cyclic changes in ovarian hormone levels, causing cyclic endometrial modifications during the menstrual cycle

Menstrual period

usually taken as the day when menstrual bleeding begins, lasting for 2-5 days

proliferative phase

Follows menstrual period and happens from days 6 to 14 after

Secretory phase

Begins at ovulation and lasts about 14 days

Proliferative phase; follicular phase

After the menstrual phase the uterine mucosa is relatively thin (~0.5 mm). The beginning of the proliferative phase, also called the _____, coincides with the rapid growth of a small group of ovarian follicles growing as vesicular follicles.