ANSC 334- Quiz 2: Female Anatomy & Histology and Endocrinology

Functions of the Female Reproduction Tract

- Gametes

- Endocrine

- Estrous and estrus

- Embryo development

- Pregnancy maintenance

- Placental development

- Fetal explusion

What is the estrous cycle?

the time from the beginning of one heat period to the beginning of the next

What is estrus?

Time when mammal females come into heat

Functions of the Ovary

- Houses female gamete

- Responds to FSH and LH

- Produces progesterone and estradiol

What is FSH?

Follicle Stimulating Hormone

- Helps with growth of follicle

What is LH?

Leutinizing hormone

- Release of follicle

What produces progesterone in the ovary?

corpus luteum

What produces estradiol in the ovary?

dominant follicle

Ovarian structure

Medulla: inner portion, houses blood vessels and connective tissue

Cortex: outer portion, CL presence, and follicle presence

Horse Ovary Structure

Medulla: outer portion

Cortex: inner portion

- Ovulation Fossa: only one site of ovulation

What is folliculogenesis?

development of follicles from their initial stage as a primordial follicle through their final stage as a Graafian follicle and ovulation. Each follicle houses one primary oocyte, which is surrounded by granulosa cells.

Primordial Follicles

- present at birth

- decrease in number as female matures

- oocyte + single layer of squamous granulosa cells

Primary Follicles

- remain at this stage until puberty

- present majority of the time

- most never ovulate and undergo Atresia

- oocyte + single layer of cubodial granulosa cells

What is Atresia?

cell death

Atretic follicles

glossy appearance with lots of shrinkage

Secondary follicles

- increase in granulosa cell layers

- oocyte + multiple layers of granulosa cells + zona pellucida + theca cells

Tertiary follicles

- maturing follicles

- theca interna and externa

- oocyte + multiple layers of granulosa cells + zona pellucida + theca cells

- antrum formation

What is the Antrum?

follicilar fluid filled; estradiol production

Graafian follicle

- Preovulatory/Dominant follicle (capable of ovulating)

- Dependent on LH surge

- Increase in the number of granulosa cells layers and fluid content

- Producing lots of estradiol (increases LH and inhibits growth of other follicles by FSH)

2-Cell-2-Gonadotropin Theory

Theca cells-Interna: LH receptors, cholesterol --> androstenodione

Granulosa cells: androstenodione --> estrogen (FSH receptors)

(incease estrogen, increase LH surge)

Membrana Granulosa

granulosa cells that are in circumference

Cumulus Oophorus

granulosa cells that make the "neck" portion

Corona Radiata

granulosa cells that lie directly to oocyte

Corpus Luteum

- responsible for production of progesterone = pregnancy establishment and maintenance

- large and small luteal cells from granulosa and theca cells, respectively

What is responsible for the yellow color in the CL?

Beta- Keratin

What is Luteolysis?

Regression of CL by Prostaglandin

Functions of the Oviduct

- Gamete/Zygote transport

- site of fertilization

- secretions

Structures of the Oviduct

- Infundibulum: surrounds the ovary, catches the oocyte

- Ampulla: thin muscularis, highly folded- secretory

-Ampullary Isthmic Junction: site of fertilization

- Isthmus: closets to uterus; moves sperm and zygote, thick muscularis, less folds- less secretory

- Uterotubule Junction: connection between oviduct and uterus

Mesometrium

broad ligament that attaches to the uterus

Mesosalpinx

broad ligament that attaches to the oviduct

Mesovarium

broad ligament that attaches to the ovary

Functions of the Cervix

Lubrication from estrogen, helps sperm pass through

Barrier from progesterone, barrier to the outside environment

- site of semen deposition in sow

Differences in shape of cervix

Cows & Ewes- annular rings

Sow- interdigitating pads

Mare- longitudinal folds

What is the Ectocervix?

closer to the vagina, stratified squamous

What is the Endocervix?

closer to the uterus, simple columnar

Functions of the Uterus

- transport of sperm

- luteolysis

- support pregnancy

- placenta attachment

- fetal expulsion

Uterus structure

Body and maybe horns

- Duplex- marsupials & rabbits

- Bicornuate- cow & mare, poorly to moderately developed

- Simplex- no uterus horns

- Bipartite- litter bearing species, highly developed

Placentones- placental attachment to the uterus

Cotylydon- fetal side

Carnucles- maternal side

Endometrium structure

(mucosa and submucosa)

- Stratum Compactum: closest to the lumen

- Stratum Spongiosum: deeper later with lots of glands

Myometrium structure

(muscularis)

- Inner circular smooth muscle layer

- Outer longitudinal smooth muscle layer

Perimetrium structure

serosa layer, outer most layer

What is a cystic follicle?

failure of a Graafian follicle to ovulate. It persists on the ovary and continues to grow. The follicle still produces high amounts of estradiol and can cause the animal to show continued estrus behavior

What is a luteal cyst?

occurs when theca interna and granulosa cells do not fill the cavity that is created upon ovulation (the rupturing of the follicle). They can cause abnormal estrous cycles and early embryonic mortality

What is a persistent corpus luteum?

failure of the CL to regress. It causes a suppresion of the estrous cycle due to its resemblance to pregnancy (i.e., progesterone is still produced and the body falsely identifies this state as pregnant)

What is the endocrine system?

Maintain homeostasis and long term control using chemical signals

Intracrine

hormone is synthesized and acts intracellularly (in the same cell)

Autocrine

feedback on cell of orgin (self)

Paracrine

diffuse to neighboring cells (that of same organ or tissue)

Juxtacrine

hormone produced by one cell to act on the neighboring cell without diffusing into circulation (passes between cells)

Endocrine

hormones enter the bloodstream and act on distant target cells

Exocrine

release secretions via duct

Neuroendocrine

hormone released by a nerve into the bloodstream to act on a distant target tissue

Neurocrine

hormone released by 1 neuron acts on another neuron (neurotransmitter)

Classical definition of a hormone

chemical messengers produced from an isolated area that travels through the bloodstream to target tissue

Modern definition of a hormone

chemical messengers produced by cells or a tissue that will bind to a specific receptor to cause an effect

Hormones are

- stimulated or inhibited by a receptor

- present in trace amounts

Steroid Hormones

- derived from cholesterol

- adrenal: corticosteroids

- gonadal: estrogen, testosterone, progesterone

Peptide/Protein hormones

- derived from proteins and peptides

- peptide: GnRH

- protein: FSH, LH

Amino Acid Derivative hormones

- derived from single amino acids

- thyroid hormones

Fatty Acid Derivative hormones

- derived from fatty acids, especially long chain

- eicosanoids (arachidonic acid): prostaglandins

- retinoids: retinol

hormone synthesis and secretion of steroid hormones

- cholesterol backbone

- precursors are enzymatically converted

- synthesized and released when needed (little storage)

what is aromatase?

enzymatic conversion of testosterone to estradiol

(cholesterol --> progesterone --> testosterone)

hormone synthesis and secretion of peptide/protein hormones

- DNA--> RNA --> Protein

- post trancriptional and post translational modifications

- peptidases break down larger proteins into peptides

- stored in secretory granules and released by exocytosis

what is hormone clearance?

concentrations that are too high in the bloodstream/hormones that have served their purpose will go through this pathway to decrease levels

Receptor

protein that binds a hormone and leads to a biological response

- concentration of receptors change depending on physiological condition

Agonists

similar shape to original hormone and can bind to cause effect in the cell

Antagonists

close enough in shape to bind to the receptor, not exact, no effect in the cell and takes places of the original hormone

Radioimmunoassay (RIA)

competition of radioactively labeled and unlabeled hormone for antibody

Enzyme Linked Immunosorbeny Assay (ELISA)

non-radioactive

spectrophotometer technique

Physiological Dose

Approximately the doses that body would normally produce

Pharmacological Dose

A 5-20x a physiological dose

- used to manipulare biochemical process

- all reproductive drugs are pharmacological doses