Histo 23- female repro

theca externa

A more fibrous theca externa with fibroblasts and smooth muscle merges gradually with the surrounding stroma.

theca interna

A well-vascularized endocrine tissue, the theca interna, with typical steroid-producing cells secreting andro- stenedione. This precursor molecule diffuses into the fol- licle through the basement membrane, and in the granu- losa cells the enzyme aromatase converts it to estradiol, an FSH-dependent function. This estrogen returns to the thecae and stroma around the follicle, enters capillaries, and is distributed throughout the body.

atretic follicles

Apoptosis of follicular cells; death of oocyte; macrophage clearance; fibrosis. Remnants of zona pellucida with cellular debris The primary or secondary follicle is detached from the granulosaThe macrophages eat the remnants Do not confuse Corpus albicans- this is the degenerated corpus luteum of the ovulated follicle The attretic follicle- is formed by any follicle @ any stage , but not one that ovulated- if you see the remnants of oocyte and zona pelucida you know it is an attretic follicle

cumulus oophorus

As the antrum develops, the granulosa cells around the oocyte form a small hillock, the cumulus oophorus, which protrudes into the antrum

muscular layer of fallopian tubes

Muscular layer Inner circular Outer longitudinal Connective tissue Medial part is more muscular

what is the dominant follicle

Only one Graafian follicle forms Dominant / Preovulatory follicle. Has LH receptors. Meiosis I completed just before ovulation --> Secondary oocyte. Only the dominant follicle ovulates! All the other follicles get inhibited except the dominant follicle

hormone function just prior to ovulation

Positive feedback of estrogen on pituitary LH & FSH increase LH surge Completion of meiosis I Ovulation Luteinization Secretion of estrogen & progesterone from corpus luteum

what follicle are present pre puberty

Prepubertal ovary - Has primordial follicles only IMPORTANT Puberty onwards - Follicular growth begins in only few follicles periodically. Most of the follicles degenerate.

fallopian tube- 4 parts

The infundibulum, a funnel-shaped opening fringed with fingerlike extensions called fimbriae (L., fringes) next to the ovary; The ampulla, the longest and expanded region where fertilization normally occurs; The isthmus, a more narrow portion nearer the uterus; The uterine or intramural part, which passes through the wall of the uterus and opens into the interior of this organ

how do androgens get to the granolas cells

Theca cells make the androgens and it is converted to estrogen in the granulosa cells

how can you tell apart the granulosa cells, theca interna and theca externa

There is a well defined basal lamina between the granulosa and theca interna The granulosa is rich in RER and is more basophilic because it is producing proteins for folicular fluid The theca interna looks vesicular because it is full of fat for the production of hormones Flat theca externa- with smooth muscle cells

antrum

This fluid accumulates, the spaces enlarge and gradually coalesce, and the granulosa cells reor- ganize themselves around a larger cavity called the antrum (Figures 22-3 and 22-7a), producing follicles now called vesicular or antral follicles.

corona radiata

Those granulosa cells that immediately surround the zona pellucida make up the corona radiata and accompany the oocyte when it leaves the ovary at ovulation.

ovulation

Trigered by LH. 14 days prior to the onset of mensus. Increase in follicular fluid and swelling of granulosa cells. Dominant follicle bulges against stigma. Stigma - damaged by plasminogen Expelled by contraction of theca externa (smooth muscle) After ovulation, LH acts on the follicle corpus luteum. In the hours before ovulation, the mature dominant follicle bulging against the tunica albu- ginea develops a whitish or translucent ischemic area, the stigma, in which tissue compaction has blocked blood flow. Secondary oocyte First polar body Zona pellucida Corona radiata Degenerates in 24 hours

what is the tunica albugenia of an ovary

Tunica albugenia -Dense irregular connective tissue

oocyte differentiation

Unilaminal means there is one layer of follicular cells Granulosa cells are derived from follicular cells Outside the granulosa is the theca interna The granulosa cells secrete fluid into the antrum (in the antrum follicle) The fluid filled cavities fuse to form one and the oocyte is pushed to the edge= mature follicle- this is much much larger than the primordial follicle Oocyte differentiation includes the following: Growth of the cell and nuclear enlargement; Mitochondria becoming more numerous and uniformly distributed; RER becoming much more extensive and Golgi com- plexes enlarging and moving peripherally; and Formation of specialized secretory granules called corti- cal granules containing various proteases. These lie just inside the oocyte's plasma membrane and undergo exocytosis early in fertilization. granulosa, in which the cells communicate through gap junctions. Follicular cells are now termed granulosa cells and the follicle is a multi- laminar primary follicle (Figures 22-3 and 22-5b) still sur- rounded by a basement membrane.

follicular fluid

Within such follicles small spaces appear between the granulosa layers as the cells secrete follicular fluid (or liquor folliculi).- Follicular fluid contains the large GAG hyaluronic acid, growth factors, plasminogen, fibrinogen, the anticoagulant heparan sulfate proteoglycan, and high concentrations of steroids (progesterone, andro- stenedione, and estrogens) with binding proteins

fate of most oocytes

Sixth month of gestation - 7 million At birth -2 million At puberty -400000 Every ovulatory cycle -Around 20 ova start maturation but only one completes and ovulates 99.9% becomes atretic -Corpora atretica (Atretic follicles)

follicular theca

Stromal cells immediately outside each growing primary follicle differentiate to form the follicular theca

what covers the surface of an ovary

Surface (Germinal) epithelium -low cuboidal; Peritoneum

Which stage of the follicle is arrested in prophase? a. Primordial follicle b. Primary follicle c. Secondary follicle d. Mature follicle e. Graffian follicle

primordial follicle

corpus albicans

Corpus albicans in 12 days Hormone production stops, apoptosis & regression Invasion by fibroblasts. Devoid of vasculature & endocrine cells Fibrous scar -whitish appearance

formation of corpus luteum

Corpus hemorrhagicum- blood clot in follicle Break in the basement membrane between granulosa and theca layer. Collapse and folding of follicle. Granulosa cells + LH Granulosa lutein cells. Theca interna + LH theca lutein cells.

corpus lute of menstruation vs pregnancy

Corpus luteum of menstruation -starts involution after 7 days to corpus albicans Corpus luteum of pregnancy -maintained for 4 months by HCG from placenta (similar action as LH) - then involutes Corpus albicans.

what makes the cortex an ovary

Cortex -Follicles in different stages, corpus luteum, albicans, highly cellular connective tissue, blood vessels

ciliated cells of fallopian mucosa

Ciliated cells in which ciliary movements sweep fluid toward the uterus, More in number and taller near ovulation (under hormonal control)

where do germ cells form

Germ cells form in the wall of the yolk sack and move to the gonadal ridge (mesoderm)

fallopian tube cross section

Fallopian tube Lumen- very irregular because of mucosal folds Mesosalphinx

physiology of the follicular cycle

Follicles secrete estrogen that has an inhibitory feedback on the pituitary E2= estradiol Note that negative feedback of estrogen and progesterone on the hypothalamus and anterior pituitary is reinforced by a polypeptide hor- mone, inhibin, also produced by granulosa and luteal cells. LH causes ovulation- and causes corpus luteum to secrete estrogen and progesterone- this causes secretery phase The increased level of GnRH causes a surge of LH release from the pituitary gland that rapidly triggers a sequence of major events in and around the dominant follicle: Meiosis I is completed by the primary oocyte, yield- ing a secondary oocyte and the first polar body which degenerates (Figure 22-10). ■ Granulosa cells are stimulated to produce much greater amounts of both prostaglandin and extracellular hyal- uronan. This hydrophilic GAG loosens these cells and rapidly increases the volume, pressure, and viscosity of the follicular fluid. ■ Ballooning at the stigma, the ovarian wall weakens as activated plasminogen (plasmin) from broken capillar- ies degrades collagen in the tunica albuginea and surface epithelium. ■ Smooth muscle contractions begin in the theca externa, triggered by prostaglandins diffusing from fol- licular fluid.

secondary (antral) follicles

Granulosa cells secreting fluid with a lot of ground substance Primary oocyte - larger Granulosa cells - Protein secreting cells; multiply & secrete follicular fluid Antrum/ vesicle - follicular fluid/ liquor folliculi -(high in ground substance) glycosaminoglycans, prostaglandin, sex steroids. Theca interna Rounded cells, lipid vacuoles, smooth endoplasmic reticulum (steroids- androgens), mitochondria Secrete androgen converted to estrogen by the granulosa cells Aromatase converts to estrogen Has LH receptors Theca externa Flat cells; Fibrocytes, smooth myocytes- Do not secrete hormones!! Just the fibrous layer

features of corpus luteum

Highly folded -YELLOW BODY Highly vascular -temporary endocrine organ Granulosa lutein cells - larger cells, vesicular nucleus, light staining cytoplasm due to lipophilic inclusions (cholesterol) -secrete progesterone and estradiol (more progesterone in this phase) Theca lutein cells -from theca interna -cells smaller and darker, small nucleus -secrete progesterone (not estrodiol!!) Influenced by LH

salpingitis

Inflammation of fallopian tube May lead to scarring / tubal pregnancy= rupture ❯❯ MEDICAL APPLICATION Tubal ligation is a common surgical type of contraception. The uterine tube mucosa can become inflamed if infec- tious agents ascend from the lower genital tract, produc- ing a condition named salpingitis after another name for these tubes, the salpinges. Mucosal damage or adhesions caused by chronic salpingitis can lead to infertility or an ectopic (tubal) pregnancy if there is blockage of oocyte or embryo transport to the uterus. In tubal pregnancies, the lamina propria may react like the uterine endometrium and form decidual cells. But because of its small diameter and inability to expand, the tube cannot contain the growing embryo and will rupture, causing potentially fatal hemorrhage

Ovulation is triggered by a dramatic increase in which hormone? a. FSH b. LH c. HCG d. Estrogen e. Progesterone

LH

what is atresia

Many primary oocytes, however, are lost through a slow, continu- ous degenerative process called atresia,

whats in the medulla of an ovary

Medulla -blood vessel, lymphatics, nerves, few interstitial cells.

layers of the ovary

Mesovarium continuous with outer lining of ovary There is a cortex and medula (smaller portion) BV are in the hilum of ovary Cortex has follicles

mucosa of fallopian tubes

Mucosa EXTENSIVELY folded (Lateral part has more folds) Simple columnar epithelium -mixture of ciliated and nonciliated cells Lamina propria

features of a primary follicle

Primary oocyte - enlarged; More organelles & cortical granules Follicular cells -series of events Flat cells become cuboidal Single layer (unilaminar) becomes multi layered (multilaminar) Granulosa cells Have FSH receptors Aromatase- specific for granulosa cells—produces estrogen Zona pellucida Theca interna -Stromal cells Primary oocyte - enlarged; More organelles & cortical granules Follicular cells -series of events Flat cells become cuboidal Single layer (unilaminar) becomes multi layered (multilaminar) Granulosa cells Have FSH receptors Aromatase- specific for granulosa cells—produces estrogen Zona pellucida Theca interna -Stromal cells

features of primordial follicles

Primary oocyte - euchromatic nucleus and organelles- in the process of synthesis Prophase I Single layer of flat follicular cells on a basal lamina (surrounding it)

review Oogenesis

Primary oocytes start meiosis I at 4th to 5th month of intrauterine life. Meiosis I arrested in prophase I. Just before ovulation - Meiosis I completed. After ovulation - Oocyte remains viable for 24 hours. Meiosis II- arrested in metaphase II After fertilization - Meiosis II gets completed.

functions of female reproductive system

Production of female gametes by oogenesis- by ovaries Secretion of hormones- estrogen, progesterone, androgens Provision of environment for the transportation & fertilization of ovum. Transportation of embryo to uterus. Appropriate location for the implantation & development of the fetus. Nutrition of the newborn- mammory gland

zona pellucida

Secreted by primary oocyte Irregular meshwork Glycoprotein - 4 types Microvilli of oocyte & filopodia of granulosa cells - Gap junction facilitates interaction. Functions: binds sperm -induces acrosomal reaction Shed only on day 5 after fertilization just before implantation. Promotes the growth of the primary oocytes- it inhibits meiosis -meiosis inhibitory factor Failure of this could lead to infertility

secretory peg cells of fallopian mucosa - what are the functions of the secretions

Secretory peg cells, nonciliated and often darker staining, often with an apical bulge into the lumen, which secrete glycoproteins of a nutritive mucus film that covers the epithelium The secretion covering the mucosa has nutritive and protective functions for both the oocyte and the sperm, including capacitation factors that activate sperm and make those cells able to fertilize an oocyte.

steps in follicle maturation

Showing the follicles in different stages Primary Secondary- you have a cavity that gets filled with fluid= antral follicle Mature follicle- space increases in size Corpus luteum shrinks to form scar that is corpus albicans

what is a graafian follicle

The secondary follicle grows in size and the antrum cavities join to form a graafian mature follicle Single large antrum Granulosa layer- thinned out Corona radiata Cumulus oophoricus- is the pedistal holding the oocyte Membrana granulosa Theca layer thicker Corona radiata -Expelled at ovulation

What is the acidophilic glycoprotein coat which surrounds the oocyte? a. Graafian follicle b. Theca folliculi c. Granulosa cells d. Zona pellucida e. Antrum

d. zona pelucida

serosa or adventitia on fallopian tubes

serosa- peritoneum

fertilization

■ Upon contact with cells of the corona radiata, sperm un- dergo the acrosomal reaction in which hyaluronidase is released by exocytosis at multiple locations around the sperm head. This allows sperm to move more easily to the zona pellucida. ■ Specific proteins on the sperm surface bind the recep- tors ZP3 and ZP4, activating the protease acrosin on the acrosomal membrane to degrade the zona pellucida locally. ■ The first sperm penetrating the zona pellucida fuses with the oocyte plasmalemma and triggers Ca2+ release from vesicles, which induces exocytosis of proteases from the cortical granules. This cortical reaction quickly spreads like a wave across the entire surface of the oocyte, with the proteases converting the zona pellucida to the impenetrable perivitelline barrier that constitutes a permanent block to polyspermy. ■ The nucleus of the secondary oocyte immediately com- pletes meiosis II, producing a second polar body and the female pronucleus of the haploid ovum. The haploid nucleus of the single penetrating sperm head under- goes decondensation, becoming the male pronucleus. Fusion of the two pronuclei yields the new diploid cell, the zygote (Gr. zygotos, yoked together).

polycystic ovarian syndrom

❯❯ MEDICAL APPLICATION Growing primary follicles can become involved in poly- cystic ovary syndrome (PCOS) that is characterized by enlarged ovaries with numerous cysts and an anovulatory state (with no follicles completing maturation success- fully.) The clinical presentation of this disorder is variable and the etiology is unclear, although increased androgen production by the ovaries or adrenals is likely involved. PCOS is a common cause of infertility in women.

follicular cysts

❯❯ MEDICAL APPLICATION Late primary or antral follicles can produce follicularcysts, which are thin-walled, fluid-filled structures withboth granulosa and thecal endocrine cells. Follicular cysts are common and usually benign, but can produce high estrogen levels and lead to menstrual irregularities. If cyst formation disrupts blood vessels blood enters the fluid, often rapidly, and produces a hemorrhagic cyst. Follicular cysts Some of the follicles grow in size but they fail to ovulate and degenerate You have well defined graulosa and thecal area- which secretes androgens Hair growth, irregular cycle (not ovulating), difficulty conceiving Fluid filled cysts