Repro Chapter 9: Folliculogenesis

What are the four parts of the follicle?

Oocyte, granulosa cells, thecal cells, follicular fluid

What is oogenesis?

development of the oocyte

What are the two types of granulosa cells?

cumulus cells and mural cells

What are cumulus cells?

nurse cells

What do mural cells secrete?

Estrogen

What do thecal cells secrete?

testosterone

What is the function of follicular fluid?

communication, stores gonadotropins

What are the components of the oocyte?

zona pellucida, vitelline membrane, cytoplasm (yolk), germinal vesicle

What is the role of the zona pellucida?

assists fertilization and may provide protection

What is the vitelline membrane?

surface layer of the oocyte

What is the role of the cytoplasm (yolk)?

contains many proteins, enzymes, and nutrients needed for survival of the zygote

What is the germinal vesicle?

nucleus containing genetic information

What are the different stages of oogenesis?

Oogonium, oocyte, ovum

What is the oogonium?

the primordial cell which develops into the oocyte

What is the oocyte?

the early, not yet fully developed ovum

What is the ovum?

the egg - the cell that is capable of developing into a new individual

How do primary oocytes form?

from mitotic divisions of oogonia

What happens to primary oocytes after they are formed?

They enter meiosis I and become dormant

Why do primary oocytes become dormant?

It helps to preserve them

When is the maximum number of oocytes formed?

During mid to late fetal life

What is atresia?

degeneration of primordial follicles

T/F: Meiosis is reactivated when primordial follicles change into primary follicles.

False

Where does meiosis resume?

in provulatory follicles

What removes the inhibitors from preovulatory follicles?

LH and FSH

Activation of oocytes occur at

estrus

What is the polar body?

vesicle for junk DNA

What is folliculogenesis?

classification and regulation of follicle growth

Where do granulosa cells come from?

the cortex

What are granulosa cells responsive to?

FSH

What do granulosa cells do?

convert testosterone to estradiol

Where do theca cells come from?

Stroma

What are theca cells responsive to?

LH

What do theca cells do?

convert cholesterol to testosterone

What are the components of follicular fluid?

Hormones, proteins, enzymes, carbohydrates

What are the different hormones found in follicular fluid?

steroids, gonadotropins, prostaglandins

What are the functions of the follicular fluid?

Supports follicle growth
Aids in oocyte development and health
Mediates granulosa cell functions

What are the three stages of follicular growth?

recruitment, selection, dominance

What is the cue for primordial follicles to grow?

We're not sure

In what state are follicles at their resting state?

Primordial follicle

The zona pellucida starts to form in what follicle?

Primary follicle

The thecal layer starts to form in what follicle?

Secondary follicle

What is the role of the thecal interna and externa layers?

to provide support and produce testosterone

What is another name for a preovulatory follicle?

Graafian follicle

How do follicles grow?

in waves and numbers

What are follicles stimulated or regulated by?

gonadotropins, growth factors, activin or inhibin

What is activin in follicles?

stimulates secretion of FSH

What is inhibin in follicles?

inhibits secretion of FSH

What are the fates of follicles?

ovulation
atresia (follicular death)
cystic (stuck in the middle. does not die. produces some hormones)

What are the two waves of follicular growth?

Ovulatory vs. non-ovulatory
Dominant vs. subordinate

What are the signals for waves of follicular growth?

LH
FSH
Inhibin

What is FSH in charge of?

Granulosa cell mitosis
Increase LH receptors
Steroidogenesis
Effects prenatal and antral follicles

What is LH in charge of?

Steroidogenesis
Effect antral follicles
Surge starts ovulation
Resumption of meiosis - Oocyte

What inhibits follicle growth?

Presence of a dominant follicle
Inadequate production of gonadotropins
Steroids (estrogens and androgens)
Inhibin

What would you do if you were a producer and you wanted to increase the number of ova produced by your prize cow?

Supplement FSH
This increases the # of follicles and gets more to the selective phase.
It also increases the number of ova produced.