Female Reproduction & Cell Division

• The female reproductive system consists of the ovary, uterine/fallopian tube/ovaduct, uterus, and vagina/vestibule
• The reproductive system produces ova, transports sperm, provides a site for internal fertilization and gestation, and secretes estrogen and progesterone (endocrine function)
• Endocrine function secretes hormones
• The stage of developmental anatomy of PGC begins with primordial germ cells appearing first in the yolk sac endoderm, then migrating through the dorsal mesentery of the hindgut following sympathetic nerve fibers, and finally populating the indifferent gonadal ridge before sex differentiation through gonad development
• The genital ridge is where the gonadal ridge takes place before cell differentiation of sex cells
• Mitosis results in two diploid daughter cells that are identical
• Meiosis creates 4 haploid daughter cells
• In males, meiosis results in 4 haploid (1n) sperm
• In females, meiosis results in one ova and three polar bodies, all haploid (1n)

Polar Bodies

• Polar bodies are a small cell division allowing the oocyte to remain large, making only the ova the fertile cell

Fate of PGC

• PGC become oogonium in the genital ridge, most of which die and do not become enclosed in a follicle
• Most germ cells in the ovary die

Oogonium

• Oogonium proliferates through mitosis
• Following mitosis, follicle formation creates the primary oocyte
• It is true that at birth oocytes are present
• Meiosis begins again at puberty
• Ovulation creates a secondary oocyte with a polar body
• Once the secondary oocyte forms, sperm entry initiates meiosis 2 , which is fertilization, and becomes the ovum of the fertilized egg turning into a zygote
• PGC rapid mitosis creates oogonium
• Most oogonia and oocytes undergo atresia, a natural process where germ cells degenerate and die

Ovary Anatomy

• The anatomic structure of the ovary consists of the cortex, medulla, and hilum
• The cortex contains follicles and corpora lutea
• The medulla contains blood vessels, lymph vessels, and nerves
• The hilum is a ligament-like region that physically connects the ovary to the rest of the reproductive tract and serves as a conduit for nerves, blood vessels, and lymphatic vessels
• The cortex is covered by superficial epithelium, a modified mesothelium > simple cuboidal
• The tunica albuginea is comprised of dense irregular CT
• The remaining stroma is composed of loose CT around follicles
• The tunica albuginea is made up of collagen and other extracellular proteins
• The soma comprises fibroblasts, reticular fibers, and ground substance
• The medulla contains blood and lymph vessels, nerves, C.T. with smooth muscle associated with mesovarium, and rete ovarii

Rete Ovarii

• Rete ovarii consist of a network of small tubules and male remnants
• Functions include transporting hormones and nutrients to developing follicles, removing waste products, and regulating ovarian blood flow

Follicles

• Follicles are defined as the oocyte and its encasing somatic cells at any development stage

Primordial Follicles

• Primordial follicles are in a dormant stage until puberty activates them

Antral/Tertiary Stage Follicle

• A unique feature of antral/tertiary stage follicles is the formation of fluid-filled spaces
• Only a few follicles make it to the pre-ovulatory stage and those that don't experience atresia

Stages of Follicular Development

• The stages of follicular development are primordial follicle, primary follicle, secondary follicle, and tertiary follicle which is also known as antral follicle

Histology of Primodial Follicle

• Histologically, a primordial follicle is known as a "resting follicle" where a single layer of squamous follicular epithelial cells covers the primary oocyte

Histology of Primary Follicle

• The histological feature of the primary follicle is a single layer of cuboidal or columnar follicular epithelial cells, now termed granulosa cells

Secondary Follicle

• The layers of the secondary follicle of continued growth include the stratified follicular epithelial cells/granulosa and developing theca which equals steroidogenic stromal cells that produce androgen, supporting growth and maturation

Theca Layers

• Theca interna (endocrine thecal cells) with lipids, vascularization and endocrine thecal cells
• Theca externa (loose C.T.) which is support based

Theca Cell Function

• Endocrine thecal cells take cholesterol and turn it into weak androgens

Follicle Steroidogensis

• The process of follicle steroidogenesis involves Cholesterol being converted to thecal androgen synthesis, which then becomes follicular cell estrogen synthesis

Two Cell Theory

• The two-cell theory involves cholesterol converting to androgen in the theca, and then androgen converting to estrogen in the granulosa, regulated by LH, FSH, and granulosa cells

Zona Pellucida

• Zona pellucida is an extracellular matrix of glycoprotein secreted by follicular epithelial cells and the oocyte
• The zona pellucida is first seen in the secondary follicle
• It plays a role in fertilization control and protects the embryo before implantation
• It protects against poly sperm, ONLY allowing ONE

Hatching

• It hatches (True), in the terminal phase of blastocyst

Tertiary/Antral Follicle

• Tertiary/antral follicle = vesicular follicle
• Follicular epithelium contains antrum-fluid filled space and well-developed thecal layers

Liquor Folliculi

• Antral liquor fluid first seems a scattered droplets and is estradiol E2 enhanced due to binding proteins that are fluid filled space

Huge Follicle names

• Huge follicle = preovulatory tertiary follicle = mature follicle = graafian follicle which increases liquor folliculi volume

Stigma

• The Site of impending rupture

LH Receptors

• Present in Theca cells - interna that turn off androgens

Granulosa cells

• Granulosa cells becomes stratum granulosum and rest on of the basement membrane

Cumulus oophorus

• Inner portion coron radiata that holds like a nest

Preovulatory Follicle sizes

• Mare 50-70m
• Cow 10-20mm
• Ewe, goat, sow - 10mm
• Bitch, queen - 2mm
• Comparing to primodial follicles

Atretic Follicles

• Atretic signs include degeneration, pyknosis, chromatolysis, and glassy membrane formation which looks like worms

Mare Ovary (Differences)

• Cortex and medulla are flipped. Vessels are located on the periphery. Ovulation
• Takes place from the ovulatory fossa

Interstitial Endocrine cells

• Theca interna cells and follicular cells from atretic follicles

Interstitial Endocrine cell function

• Steroidogenesic - not in all species

Feedback

• Positive and or negative feed back depends on cycle

Time of Cycle

• LH hormone or leutinizing hormone spikes prior ovulation

Negative feedback

• Estradiol E2 Decreases in ovulation

Positive feedback

• Progesterone (P4) increases in ovulation

What produce Progestone

• corpus luteum produce Progestone

Ovulation Switch

• Lh surge determines it

Result of Lh surge

• change follicular estradiol production in prostaglandin production

Function of Prostaglandin

• Increases collagegeanse, the digestion of of the follicular wall stigma to ovulation

Follicle OutCome

• it ruptures, then oocyte with corona radiates escapes into peritoneal cavity, and goes through the infundibulum of uterine tube

Corpus hemarragic

• A temporary structure that forms in the ovary after ovulation
• Result in the rupture of follicle after ovulation

Ovulatory species

• Cat needs copulatory stimulus to ovulate, others usually do spontatinously

At Ovulation

• 1st Meiotic division has been completed
• The secondary oocyte enters peritoneal cavity to uterine tube
• The oocyte only lives for ~1 day

Process Occurence of ferilization

• Occurs in uterine tube were the 2nd meiotic division takes place

Lutenization

• formation from remaining post-ovulatory follicular and Theca Interna cells
• • increased cell size > seteroidogenic capibilty
• • Granuloma cell protein changes and becomes steroidogenic cells
• • Cells can cause mitosis

Gonadrotropin

• FSH (Gonadrotropin) drives estrogen production, whith LH surge, follicle primary oocyte with corona leave, then fill in with mitotis to produce progestrone

Lutein color?

• Lutein has a yellow pigment

Corpus albicans

• Corpus has a white pigment

Synonyms for uterine tube

• Oviduct / Fallopian tube

Fertilization Location

• Ampulla

Tubic Microspopic

• Tunica Muscosa - sub mucosa
  • Many folds - plicae
    • Epithelium: Simple/Peudostratified Columnar - 2 Cells - Cilliated with microvilli and allow movement - Microvilli that create nutrients

Tunica Propia of the Uterine Tube

• lamina propia- submucosa
  • Loose connective tissue that is very cellular
    • Consist of lymphocytes, plasma cells, mast cells and eosinophils

Tunica Muscularis of the Uterine Tube

• Made of smooth muscle that has a inner circular and predominant muscle

Serosa of the Uterine Tube

• Tunica serosa is, a serious membrane that in turn is visceral peritoneum - Meso epithelium that opens to peritoneal cavity - Loose connective tissue

Functions of the uterine tubule

• Fimbraie of infudibilum
  • secure ovulated primary oocyte - cili transport oocyte to amulla where fertalization takes place - Cilia and muscles contract together at zygote to isthmus
    • Muscle contraction of isthmus propel zygote to uterus
  • Muscle contraction of uterus and uterine tube transport spermatozoa to ampulla

Uterine Tube - Pig

• Thickness of muscle increased from infundibulum > isthmus
  • Cillia relies on the contraction from muscles

Uterus Anatomy in gross

• Horned with bicornuated uterus
• Body
• Cervix

Uterus Morpholiges

• Duplex uterine horns where it as two cervix
• Bipartite uterine with one cervix
• Bicornuatia uterine with body and horns
• Simple with body and cervix = Humans

Uterus Tunics

• Tunica Mucosa - Submucosa that can be defined as the endometrium
• Tunica Muscularis = Myometrium
• Tunica Serosa = Perimetrium

Features of the Endometrium

• Muscosa - Submucosa - Epithelium is simple/presudostratified columnar - Has uterine glands, simple coiled/Branched tubular, lined with simple columnar epithileam - lamina piropia- Submucosa - Loose connective Tissue - Lymphocytes with plasma cells with mast cells and WBC's
• Highly dynamic
  • It contains melanocytes

Caruncle

• Is only found ruminants, its endometrium modifications. It is a area of the placental attachment and devoid of utrine glands

Myometrium

• Has smooth muscle in both circular and longitudinal layer

Perimetrium

• tunca Serosa - serosa
  • Meso epithilium with connective tissue

Cervix

• Inbetween vagina or the other parts

Mucosa layer

• the mucosa layer of of the cervix is highly coated

Epitheium

• is simple columnar with ciliated cells
  • sectretes mucus

Propiua Layer

• • dense irregular connective tissue to loose

Tuna Musculara Layer

• Muscle is tunular and as some muscles like
  • smooth muscle - inner circular - Outer longitudinal
    • the t serosa is a typical
    • The cervix is a construction between uterine body and vaginal acting,

Vestibule tunics

• • 4-2 vestibutes mucosa serosa and the t muscularis

Serosa - adventita end

adventitia- cudal end

Volva

• the labia - skin with aborline and cebaceous glands

Fortnix

• • it is a blind touch at the ends

Estrous Cycle

• a recurring cycle in periods with physiological behavior

Estrus

• • specific period in which the Estrus occurs

Phases of estrous

• Preotrua Dietsrus(5 anus). Estaus and metetrous

factor

• enviroment
• Food
  • internaly
  • age or body condition
  • genetic

Hypathalmus

• secrete gnrh factor

Gnrh

• releases fsh lh from the adenohypophysis badophils

FSH AND Lh

• Ovarian folliculur development

developing follicle

Estrogens. Communicate wit body to prepare for fertilization, and thicken uterine wall, and uterus.

• FSH stimulates ovarian follicular development
• Developing follicles secrete estrogens into follicle and blood
• Estrogen concentration increases as follicle matures and stimulates growth and branching of uterine glands; thickens the endometrium, and creates an environment for fertilization

Proestrus (Definition)

• Estrous Cycle Phase:* Characterized by follicular growth, rising estrogen concentration, and endometrial development.

Estrus Definition

• Hormonal Receptivity:* Period of sexual receptivity occurs

Ovulation Concentration Definition

Occurs during the overaliton in the species.

Folliculur phase of the cycle

• Follicular Phase Definition:*
• Proestrus
• Estrus

Estrogen Concentration

• Changes post Estrus:*
• Decline: Estrogen concentration decreases

Metesterus Definition **

• Corpus Luteum Development:* A period marked by corpus luteum (CL) development and initial progesterone secretion.

Diestrus Definition **

• CL is actively secreting progesterone

Metetruus and Diestrus create

• Luteal which if pregnancy dossent fall off decrease, and a new follicle growths
• Anetrus that isnt in the ovarian cycle
• Phases Defined:* Metestrus and diestrus collectively create the luteal phase of the cycle.

Anestrus (Definition)

A period of ovarian inactivity, where the animal is "not cycling."

• Follicular Growth:* As progesterone concentrations decline, increased FSH and LH releases may stimulate new follicular growth, and the secretion of estrogen

Polly estrous Animsls

• Animals undergo multiple estrous cycles per year

Mammary Gland Histology

consist of modified system . Respond to compound and tubuloalveolar surface ectoderm invaginates into underlying mesoderm, very slow growth until puberty, estrogen (ovary) stimulates branching of the duct system and fat accumulation

Mammart Structure

• Compound is found

Milk production is asynchronous across lobules, whether for storing or filling, don't release protien for lactation

• Has cells with well developed RER and lipid droplets
• lipd secretion piece of cell pinch off, Protien secretion - protein component of milk, and compound structure

Secretion of Glandular lips

• Apolcrine

Protiens are

• merocrine

Alveois suround

• the myoepithelial cells surround alveoli, respond to oxytocin with contraction, squeezing alveolus and cause milk ejection

Interducts

• Interlobular - visualize

Inter - interlobular fuse, fuse more forming lactiferous ducts the . . Anastomous for finaly

Involution

• After lactation and the alveolar cells degenerate ducts and few small remain that regrow again with next pregnancy

bird overy

• Many only have one the the left regressed

Overview of topics related to the female reproductive system and cell division (meiosis, and mitosis). Topics covered include the ovaries, the function of the reproductive system and the developmental anatomy of PGC. Mitosis results in two identical diploid cells and meiosis creates 4 haploid cells.