Exam II Review

Remember to study the hormone profiles of the estrous cycle!!!

Describe two ways that the ovary of a mare is different from other animals.

1. Medulla and cortex are inverted

2. Ovulates at ovulatory fossa

What are the 4 distinct, concentric layers of tissue found in the female reproductive tract?

1. Lumen - inner cavity

2. Mucosa and submucosa - connective tissue layers

3. Smooth muscle

4. Serosa - outer lining

Name and describe the 3 segments of the oviduct.

1. Infundibulum - oviduct opening, oocyte “catcher’s mitt”

2. Ampulla - larger first half of the oviduct packed with ciliated epithelium

3. Isthmus - very muscular, smaller second half of the oviduct

The _________ ligament houses the vascular supply, lymphatic drainage, and nerves, and supports the entire reproductive tract. The portion that supports the oviduct is called the _________. The portion that supports the ovary is called the ____________. The portion that supports the uterine horns and body is called the _________.

broad, mesosalpinx, mesovarium, mesometrium

List the tissue components of the uterus.

1. Perimetrium - outer serous layer

2. Myometrium - muscular layer

3. Endometrium - mucosa and submucosa

What is the function of the cervix?

mucus production and sperm barrier/transport

What is the function of the vagina?

copulatory organ and birth canal

During proestrus, what is happening to progesterone concentration? Estrogen concentration?

Decreasing progesterone, rising estrogen

What type of GnRH secretion pattern is observed during proestrus?

tonic

What type of gonadotropin secretion pattern is observed during proestrus?

Surge

During estrus, which hormone is at its peak concentration?

Estrogen

During estrus, what type of GnRH secretion pattern is observed?

Surge

During estrus, what type of gonadotropin secretion pattern is observed?

Surge

During diestrus, which hormone is at its peak concentration?

Progesterone

During metestrus, what is happening to estrogen concentration? Progesterone concentration?

Decreasing estrogen, increasing progesterone

During what stage of the estrous cycle are behaviors observed that indicate the female is receptive to the male?

Estrus

Which stage consists of luteinization?

Metestrus

During which stage is the CL fully functional?

Diestrus

Diestrus ends with…

luteolysis

Describe two situations in which anestrus may occur.

1. Female is pregnant

2. Female is lacking in nutrients

What are two differences between the estrous cycle and the menstrual cycle?

1. Estrous cycle is split 60/40, menstrual cycle is split 50/50

2. Menstrual cycle occurs only in primates

What stages make up the follicular phase?

Proestrus and estrus

What STARTS the follicular phase?

Luteolysis

What hormone must rapidly decline during proestrus? Why?

Progesterone, due to CL lysis and so antral follicles can mature for ovulation

Which hormone has positive feedback on GnRH and, once it reaches its threshold concentration, results in a preovulatory surge of gonadotropins?

Estrogen

Atresia

failure of follicles to develop

Which hormone stimulates recruitment and selection of follicles?

FSH

Which hormone is the primary hormone responsible for ovulation?

LH

2-cell 2-gonadotropin model

explains how ovaries produce sex steroids through cooperation of 2 cell types and 2 hormones

What are the cells and hormones of the 2-cell 2-gonadotropin model? What classification are the other 2 hormones involved?

Theca + LH = androgens*

Granulosa + FSH = estrogen*

*Steroids

Ovulation

follicle rupture and oocyte release

What changes occur in blood flow and blood vessels of the ovary and follicle prior to ovulation?

Edema (swelling) and hyperemia (increased blood flow)

What secretions contribute to breaking down connective tissue to cause ovulation?

Hyaluronic acids, collagenase

Which hormone causes contraction of the myoid (muscular) components of the ovary to increase pressure on pre-ovulatory follicles?

prostaglandin

In the female gamete, what triggers the removal of meiotic inhibitions?

LH

What are the 3 major processes of the luteal phase?

1. Ovulation

2. Luteinization

3. Luteolysis

What is the dominant hormone of the luteal phase?

Progesterone

What 2 major events mark the beginning and end of the luteal phase?

Ovulation and CL regression

What 2 stages of the estrous cycle occur during the luteal phase?

Metestrus and diestrus

Luteolysis

CL disintegration

Luteinization

process where theca and granulosa cells turn into luteal cells

What hormone is responsible for luteolysis?

PGF2a

What hormone(s) cause luteinization?

LH

During what stage would a CH be observed?

immediately after ovulation; proestrus

Approximately how many days does it take until a CL is fully functional?

14

Which cells develop into the large luteal cells?

Theca

Which cells develop into the small luteal cells?

Granulosa

What hormone is secreted by the luteal cells of the CL?

Progesterone

___________, secreted by the CL, has negative feedback on ___________. This inhibits secretions of ___________.

Progesterone, anterior pituitary, GnRH

Where is PGF2a produced and secreted in the female tract?

Uterine endometrium

How is PGF2a transported to the ovary?

the vascular countercurrent exchange mechanism

Why is a unique transport method necessary for PGF2a?

It would be diluted in systemic circulation and metabolized quickly in the lungs

How does the luteal cell produce progesterone?

Cholesterol imported via the LDL → transported to mitochondria, where it is converted to pregnenolone → in the smooth ER, pregnenolone is converted to progesterone

When LH binds to its receptor during the synthesis of progesterone, the downstream response…

activates several protein kinases that enzymes will use during the process

What is the difference between functional and structural death of the CL?

Functional luteolysis is a decrease in progesterone production due to a rise in PGF2a levels and less LDL and LH receptors.

Structural luteolysis is the physical breakdown of the CL; PGF2a receptor complexes open calcium channels on the CL, and the higher intracellular calcium causes apoptosis.

How does a follicle produce estrogen?

At the beginning of the estrous cycle, the hypothalamus releases GnRH, which stimulates the anterior pituitary gland to release FSH.

FSH promotes the growth of antral follicles and the subsequent development of Granulosa cells and theca cells.

Theca cells produce androgens. When stimulated by FSH, Granulosa cells will convert the androgens to estrogen, facilitated by the enzyme aromatase.

How does the LH surge lead to ovulation?

A high concentration of estrogen prior to ovulation will prompt the pituitary gland to release an LH surge into the bloodstream. This surge sends a chemical signal to the ovary that will cause it to ovulate within 28 hours.

How does the internal environment of the female reproductive tract change with estrogen dominance vs progesterone dominance?

Estrogen dominance: prepping for fertilization and pregnancy

• Endometrium thickens

• Cervical mucus is watery and thin to facilitate sperm movement

• Increased lubrication may raise risk of infection

Progesterone dominance: maintaining pregnancy

• Stabilizes the endometrium to prevent hyperplasia

• Cervical mucus thickens and creates a “plug” or a “seal”

• Immunosuppressive effects prevent the mother’s immune system from attacking the fetus