Female Endocrinology System:

What are the basic components of the female reproductive system?

Ovaries (and ovarian structure), Oviduct, Uterus, Cervix, Vagina, and External Genitalia (vulva).

What are the 5 functions of female gross anatomy?

1. Develop and ovulate ovum/oocyte

2. Estrogen and Progesterone production

3. Pregnancy attainment and maintenance

4. Parturition

5. Lactation

...Repeat

Describe the Ovaries.

Paired Organs that vary in shape and size among the livestock species.

What are the main functions of the Ovary?

Gametogenic and Endocrine. Gametogenic functions include the production of eggs (gametogenesis) and Endocrine production of hormones (steroidogenesis).

Gametogenesis in the ovaries is the...

production of eggs (Gametogenesis).

Endocrine in the ovaries is the...

production of hormones (Steroidogenesis).

What are the specific hormones secreted from the ovaries?

Estrogen and Progesterone.

The Ovary is dived into...

the ovarian cortex (outer) and the medulla (central) portions.

What all does the Ovarian Cortex include?

The ovarian structures (follicles and corpora lutea) and is where ovulation occurs. Outer 2/3 of the ovary.

What all does the Ovarian Medulla include?

Lymphatics, Nerves, and Vasculature. Inner 1/3 of the ovary.

What species is the opposite of every other species when it comes to the Ovaries.

Horses; their ovaries are inside out; the medulla is the outer portion and the cortex is the inner portion, ovulation only occurs at the ovulation fossa.

What is the Germinal epithelium?

Portion of the ovary that composes the surface, continuous w/ peritoneum. A single layer of cuboidal cells prevents adhesion and breaks at ovulation. Not the origin of germ cells.

What is the Tunica Albuginea?

Portion of the Ovary that surrounds it entirely. Composed of dense connective tissue, provides structure.

What are the parts of the Prenatal phase?

Oogonia --> Follicle formation --> Primordial --> Follicle activation --> Primary --> follicle growth --> Secondary phase.

What are the parts of the Antral phase?

Tertiary --> Follicle growth, recruitment, selection, dominance --> Preovulatory phase

The basement membrane, granulosa cells, theca interna cells, theca external all combine to form the ________ ________ when the follicle is ovulated.

Corpus Luteum.

The corpus luteum is responsible for...

progesterone production.

Progesterone is...

Progestational, helps to maintain pregnancy.

The Antral follicle secretes....

Estrogen, initiates estrus and the ovulating follicle.

Following ovulation, the remaining follciular cells morph into first the...

CH, then the CL, and Lastly the CA.

What is the Cropus Hemorrhagicum (CH: Corpora Hemorrhagica)?

Also known as the Bloody body, during ovulation, small blood vessels rupture, causing local hemorrhage and an ovarian cavity. The remaining granulosa and theca cells are pushed to the apex of the follicle.

What is the Corpus Luteum (CL: Corpora Lutea)?

Also known as the Yellow body, theca cells and granulosa cells differentiate into luteal cells, producing progesterone, (P4).

What is the Corpus albicans (CA: Corpora Albicantia)?

Also known as the White body, if fertilization does not occur, the CL regresses to form the CA. Composed of degenerated CL and scar tissue, it has no function.

Luteal cells originate in the...

theca interna and granulosa cells.

Progesterone is known as the...

hormone of pregnancy

Why is Progesterone known as the hormone of pregnancy?

Blocks myometrial contractions and behavioral estrus, increases endometrial secretions (acts as a source of nutrients for the early embryo), and regulates luteinizing hormone (LH).

What are the Gametogenic ovarian functions?

Development, Maturation, and Ovulation of Oocytes.

What are the Endocrine ovarian functions?

Estrogen, Progesterone, Oxytocin, Relaxin, Inhibin, and Activin.

What is the 2 cell 2 Gonadotropin Model?

The 2 cells are the Theca Interna cell and the Granulosa cell. The 2 gonadotropins are LH and FSH. The overall function is estrogen production. LH from the Anterior pituitary binds to its Receptor on theca interna cells (G protein-coupled cells). LH binding results in the conversion of cholesterol into testosterone; testosterone can then cross the basement membrane and enter the granulosa cell. Testosterone is then either stored or converted to Estrogen by aromatase when a FSH molecule binds to the granulosa cell. Estrogen then travels from the granulosa cell to the follicular fluid. E2 is then transported out and into the blood, where it can act in the ovarian system or the brain.

What are the Specific steps of the 2 cell 2 gonadotropin model?

LH from the anterior pituitary travels through the blood to get to the receptors on the cell membrane of the Theca interna cell. LH binds to the membrane, activating secondary messenger systems to convert cholesterol to Testosterone. Testosterone crosses the basement membrane and reaches the antral follicle, where it binds to the granulosa cell membrane. Testosterone is then stored and is ready to be activated when needed, converted by FSH from the anterior pituitary, and binds to the cell membrane receptor on the granulosa cell membrane. Aromatase is then activated, allowing the conversion of testosterone to estrogen, which is then circulated throughout the body for its various functions.

When a female is pregnant the CL is...

maintained

When a female is not pregnant the CL is...

transformed into a CA, so the body can recycle.

Describe the Uterus.

Serves as the connection between the cervix and the oviducts, houses the developing fetus, and consists of two uterine horns in most species (site of fertilization in most species).

The degree to which the uterine horns develop is the basis for...

classification of mammalian uteri.

What are the three types of Uteri?

Simplex, Duplex (Marsupials) and Bicornuate (Livestock)

What are the two different types of Bicornuate horns?

Poorly (Mare) to Moderate (Cows) (uterine body is common in both) and Highly developed (Bitch, Queen, Sows), no uterine body.

What are the Uterine Layers?

Endometrium, Myometrium, and Perimetrium.

Metrium =

Uterus

The Endometrium is the...

secretory layer of the uterus. Composed of the Mucosa and Submucosa.

Mucosa lines the...

lumen and uterine glands.

A increase in secretions will occur to increase...

embryo development and sperm survival.

An increase in estrogen in the endometrium results in...

Glands coiling.

An increase in progesterone in the endometrium results in the glands becoming...

fully secretory.

What are caruncles?

Found in ruminants, vascular protrusions that form on the maternal side of the placenta during pregnancy.

The Endometrial lining is what is...

sloughed in primates during menstruation does not occur in every livestock species (menstrual cycle vs. estrous cycle).

What are the functions of the uterus?

Helps to control estrus cyclicality, Sperm transport, Implantation/Placentation, Pregnancy, and Parturition.

How does the uterus control estrus cyclicity?

PGF2a product by the uterus causes CL death (stops progesterone production).

How does the uterus assist in Sperm transport?

Contractions of the myometrium are stimulated during mating, contractions help propel sperm to the site of fertilization, Sperm undergo capacitation.

How does the uterus assist in Implantation/Placentation in Ruminants?

Caruncles, which are highly vascularized protrusions on the endometrium, allow for non-secretory functions and attach to the fetal placenta.

How does the uterus assist in Implantation/Placentation in Sow and Mares?

Endometrial folds increase the uterine surface for the fetal placenta.

How does the uterus assist in pregnancy?

Houses the Fetus.

How does the uterus assist in parturition?

The uterus contracts during parturition to expel the fetus and then undergoes involution.

Describe the Cervix.

Barrier between the vagina and the uterus; projects cuadually into the vagina. Composed of a lumen/cervical canal (connective tissue, smooth muscle, and secretory tissue, Mucosa (columnar epithelium +/- cilia) and submucosa ) surrounded by multiple folds or rings that develop to varying degrees in different species. AI site of semen deposition.

An increase in estrogen in the cervix results in a ....

clear watery mucous secretions (most prominent in the cow and the ewe).

What are the Functions of the Cervix?

Mucous secretion during estrus (Increase estrogen) in cattle, ewes, sows, and mares. Acts as a reservoir for sperm, a cervical seal of pregnancy.

How does the cervix act as a mucous secretion during estrus?

Lubricates the vagina and facilitates sperm transport and survival.

How does the cervix act as a reservoir for sperm?

Cervical crypts trap sperm of poorer quality, facilitating the travel of healthy sperm.

How does the Cervix act as the cervical seal of pregnancy?

Isolates the fetus from the external environment during pregnancy, under the influence of increased progesterone, mucus becomes viscous and seals the cervix.

Describe the Vagina.

Copulatory organ, site for expulsion of urine, composed of a poorly defined muscle layer.

What tissue type composes the Cranial vagina?

Columnar epithelium and is highly secretory during estrus.

What tissue type composes the Caudal vagina?

Stratified squamous epithelium, cycle stage determines secretion and thickness.

What is the Fornix vagina?

Cervix protrudes into the anterior vagina creating a blind pocket/fornix in the cow, ewe, and mare.

Cyclcity is regulated highly by the...

2 Cell 2 Gonadotropin model.

Function between the Reproductive tract and Brain is...

controlled by communication. The hypothalamus releases GnRH, which travels to the Pituitary gland. The anterior pituitary gland releases LH and FSH, which travel to the ovary. The 2-cell 2-gonadotropin model occurs and results in Estradiol (Estrogen).

The hypothalamus is the...

Relay center, secretes GnRH.

Gonadotropin secretion occurs from the...

Pituitary gland, LH and FSH releasing.

Define Estrus.

Period of sexual receptivity (heat, standing heat, lordosis).

Define Estrus Cycle.

A series of predictable reproductive events (estrus/ovulation to estrus/ovulation). Allows for non-pregnant females repeated opportunities to get pregnant. Is conns throughout adult life, temporarily interrupted by Anestrus (noun).

What is are some causes of Anestrus?

Pregnancy, Lactation, season of year (species specific), inadequate nutrition, stressful environment and (or) management conditions/pathologic conditions.

What are the two main phases of the estrus cycle?

Follicular phase (20% of the cycle, growing follicles +estrogen dominance) and the Luteal Phase (80% of the cycle, corpus luteum + progesterone dominance).

What occurs during the Follicular phase?

Growing of follicles and estrogen secretion.

What occurs during the Luteal phase?

Corpus Luteum and Progesterone Secretion.

What are the 4 stages of the estrus cycle?

Proestrus, Estrus, Metestrus, and Diestrus.

Describe the Proestrus stage.

2-5 days in length, transition from progesterone to estrogen dominance, formation of ovulatory follicles occurs, and an increase in estrogen secretion.

Describe the Estrus stage.

Hours to days, depending on the species. Presence of ovulatory follicles, estrogen drives behavioral estrus in the absence of progesterone: Sexual receptivity + Peak estrogen + LH surge + ovulation.

Describe the Metestrus stage.

During the period between ovulation and initial CL formation, luteinization of the ovulated follicle occurs, and secretion of estrogen and progesterone is low.

Describe the Diestrus stage.

Longest stage of the cycle, CL becomes fully functional with sustained progesterone (+LH), increased progesterone prepares the uterus for pregnancy, if not pregnant, luteolysis occurs (Uterine PGF2a).

What two stages make up the follicular phase?

Proestrus and Estrus.

What two stages make up the Luteal phase?

Metestrus and Diestrus

What type of hormone is GnRH?

Peptide Hormone.

Where is GnRH sourced?

Hypothalamus.

What is the female target of GnRH?

anterior pituitary

What is the female action of GnRH?

Release of FSH and LH

What type of hormone is Oxytocin?

Peptide.

What is the source of Oxytocin?

Synthesized by the hypothalamus, stored in the posterior pituitary gland, synthesized in the corpus luteum.

What is the female target organ of Oxytocin?

Myo and endometrium, myoepithelial cells.

What is the female action that occurs because of Oxytocin?

Uterine motility, synthesis of PGF2a, milk ejection.

What type of hormone is LH?

Glycoprotein

What is the source of LH?

anterior pituitary

What is the female target of LH?

Ovary (Theca interna, CL).

What is the female action of LH?

(+) ovulation, CL function and progesterone secretion, follicle development.

What type of hormone is FSH?

Glycoprotein.

What is the source of FSH?

Anterior pituitary

What is the female target of FSH?

Ovary (granulosa cells)

What is the female action of FSH?

Follicle development, estradiol synthesis.

What type of hormone is Prolactin?

protein hormone

What is the source of Prolactin?

anterior pituitary

What is the female target of prolactin?

Mammary cells, CL (rat/mouse).

What is the female action of Prolactin?

Lactation, maternal behavior, CL function (some species).

What type of hormone is Estradiol?

Steroid hormone.