Chapter 8 Flashcards by Hampton Watkins

What is the driving force for initiation of the follicular phase?

luteolysis

How well did you know this?

Not at all

Perfectly

What does the follicular phase consist of?

proestrus and estrus

How well did you know this?

Not at all

Perfectly

Where are LH and FSH released from?

anterior pituitary lobe

How well did you know this?

Not at all

Perfectly

What four events take place in follicular phase?

1) Gonadotropin release
2) follicular preparation for ovulation
3) sexual receptivity (estrus)
4) ovulation

How well did you know this?

Not at all

Perfectly

What is the follicular phase goverend by?

hypothalamus, anterior lobe, ovary (ovarian estrogen secretion)

How well did you know this?

Not at all

Perfectly

What is the surge center also known as?

preovulatory center

How well did you know this?

Not at all

Perfectly

What is the positive stimulus received by the surge center?

where it releases basal leaves of GnRh until estradiol threshold concentration is reached

How well did you know this?

Not at all

Perfectly

What makes up the tonic GnRh center? (hypothalamic nuclei)

ventro-medial and arcuate nucleus

How well did you know this?

Not at all

Perfectly

What makes up the surge center (hypothalamic nuclei)?

preoptic nucleus, anterior hypothalamic area, and suprechiasmatic nucleus

How well did you know this?

Not at all

Perfectly

What causes GnRH secretion directly caused by?

depolarization (action potentials) from cells bodies of nuerosecretory cells

How well did you know this?

Not at all

Perfectly

What is the release of GnRH in the tonic center compared to?

water faucets being gradually turned on (basal secretion)

How well did you know this?

Not at all

Perfectly

How often does tonic secretion of GnRH occur?

entire estrous cycle

How well did you know this?

Not at all

Perfectly

How often does the preovulatory surge of GnRH happen during estrous?

once

How well did you know this?

Not at all

Perfectly

What can the preovulatory surge of GnRH be compared to?

a faucet fully open for a short period of time

How well did you know this?

Not at all

Perfectly

What type of feedback is the surge center sensitive to?

positive

How well did you know this?

Not at all

Perfectly

How often do small GnRH episodes in the tonic center happen in the follicular and luteal phase?

Follicular: every 1.5 - 2.0 hours
Luteal: every 4 to 8 hours

How well did you know this?

Not at all

Perfectly

How low is neural secretion of GnRH in tonic center? What does this cause?

5 pg/ml and low LH secretion

How well did you know this?

Not at all

Perfectly

What type of feedback does low estradiol concentrations cause to the preovulatory center?

negative

How well did you know this?

Not at all

Perfectly

What does low estrodiol concentrations cause?

low firing of GnRH nuerons

How well did you know this?

Not at all

Perfectly

What type of feedback does high estradiol concentration cause to the preovulatory center?

positive

How well did you know this?

Not at all

Perfectly

When do the follicles begin to produce more and more estradiol?

proestrus

How well did you know this?

Not at all

Perfectly

When is the preovulatory center turned on?

when estradiol reaches threshold concentration

How well did you know this?

Not at all

Perfectly

What is essential for initiating the follicular phase of estrous?

GnRH elevating

How well did you know this?

Not at all

Perfectly

What is the surge center ultimately responsible for?

secretion of large quantitites of GnRH thus causing the surge of LH that causes ovulation

How well did you know this?

Not at all

Perfectly

What is the surge center ultimately responsible for?

secretion of large quantities of GnRH thus causing the surge of LH that causes ovulation

Follicular growth and degeneration is known as what?

follicular dynamics

What do the dynamics of the antral follicles consist of?

recruitment (emergence/growing), selection (the growing follicles that have not undergone atresia), dominance, atresia

Which animals have a cohort (group) of follicles become dominant?

gos, cats, pig,

What animals have only a single follicle that becomes dominant?

cattle, mares, and women

What do growing/antral follicles secrete?

estradiol and inhibin

What does monotocous species mean?

giving birth to a single offspring

What does polytocous species mean?

litter bearers

What effect do large preovulatory follices have on other follicles?

inhibitory effect (less blood supply to some follicles) and less FSH

How does atresia occur?

continuously throughout folliculogenesis`

What percent of follicles undergo atresia?

90%

Atretic antral follicles are in what?

atresia (degenerative)

What occurs during the estrous cycle when talking about follicular development?

follicular waves

What can't happen when progesterone dominance is present?

complete follicular dominance and ovulation

What happens when luteolysis happens?

Dominant follicle will ovulate

Endocrine condition for final follicular development will only exist if what happens?

luteolysis and progesterone decline

What is the most important imaging technique used in reproductive research and diagnostic?

ultrasonography

What can ultrasonography be used for?

pregnancy diagnosis, description of ovarian structures, fetal aging/growth

What is the primary advantage of untrasonography?

minimally invasive and used without surgery.

What is the majority of time a follicle lifetime is in?

preantral

What is cyclic recruitment when talking about follicular dynamics a result of?

elevated FSH levels after puberty

What is the primary role of LH?

to promote final growth and maturation of dominant follicles and to stimulate ovulation

What cycles have a maintained LH pulse frequency?

metestrus and diestrus

Why do most follicles undergo atresia?

the lack of LH receptors on granulosal cells

What is the purpose of FSH?

to stimulate emergence of follicles to begin growing and secrete estrogen and inhibin

FSH dependent?

recruitment and selection follicles

LH dependent?

mature selected, dominance, and preovulatory follilcles

What does the binding of LH to its receptors activate?

cholesterol to testosterone via theca cells, testosterone diffuses out of the theca interna and into granulosal cell that contain FSH receptors that bind and cause the conversion of testosterone to estradiol via enzymes in order to induce preovulatory LH surge

What is so important about the granulosal cells?

They synthesize LH receptors that need to be present so that the preovulatory LH surge can exert its full effect on the follicle to cause ovulation.

What does the 2 Cell, 2 Gonadotropin model describe?

estrogen synthesis

What is the primary target for estradiol?

the reproductive tract tissue

What types of cells indicate estrus?

cornified and squamous cells

What thinkens in the vagina due to estradiol?

mucosa

What are some effects of estradiol on the reproductive tract?

increased blood flow/musosal secretion, genital swelling, leulocytosis

What produces mucus?

cervix and cranial vagina

What is the purpose of mucus from the cranial vagina and cervix?

lubrication, flushing foreign material out of the tract, providing privileged pathways for spermatozoa to travel

What happens to uterus in response to estradiol?

uterine gland growth

What happens to oviducts in response to estradiol?

increased secretory rate to allow for gamete and fluid transport

What is increased blood flow called?

hyperemia (major estradiol effect)

What are the major effects of increased blood flow?

increased secretion (secretory activity), leukocytosis, genital swelling

What reproductive tract tissue responds dramatically to estrogens?

mucosal epithelium

What do dominant follicles produce?

angiogenic factors

Ovulation is brought about by?

elevated blood flow, breakdown of connective tissue, ovarian contractions

What enzyme is produced due to the progesterone produced following the LH surge?

collagenase

What do prostaglandins cause?

ovarian contraction and aid in follicular remodeling

What are the two types of ovulators?

spontaneous ovulator and reflex (induced) ovulators

Do spontaneous ovulators require copulation?

no (cow, women, sow, mare)

Do reflex (induced) ovulators require copulation?

yes (rabbit, ferrit)

Can reflex ovulators be induced artificially? How?

yes, electrical and mechanical (tactile stimulation)

What are camelids?

modified induced ovulators (camels, alpacas, llamas)

What is important for modified induced ovulators when inducing ovulation?

seminal plasma

What are ways to induce folliculogenesis and ovulation (manipulate ovulation)?

hormonally induced ovulation and superovulation

What is hormonally induced ovulation?

premature luteolysis using prostaglandin F2a to decline progesterone

What is superovulation?

administration of gonadotropins (equine/human chorionic gonadotropin, FSH, LH, GnRH

What is the principle of superovulation?

providing higher levels of FSH to that greater number of follicles are recruited and selected

When does oocyte maturation occur?

lifetime of female conceptus (beggining embryonic development)

What are the 4 phases of oocyte maturation?

mitotic division of primordial germ cells (prenatal), nuclear arrest, cytoplasmic growth, resumption of meiosis

What does cytoplasmic (oocyte) growth involve?

large cytoplasm and zona pellucida

What is the zona pellucida?

translucent band around the cytoplasm of the oocyte

What forms during oocyte maturation that is important for transportation?

junction complexes with their gap junctions

What mediates oocyte growth?

granulosal cells

When has the oocyte attained its full cytoplasmic size?

antrum fromation

When does the oocyte resume meiosis?

when follicle enters dominance

What is the main inhibitor of meiotic resumption?

cAMP and oocyte meiotic inhibitor

What caues cAMP to no longer inhibit the oocyte?

granulosal projections dissociate

Which occurs first in dogs and foxes, ovulation or meiosis resumption?

ovulation