FEMALE REPRODUCTIVE SYSTEM

What are the components of the female reproductive system?

Ovaries, oviducts (uterine/fallopian tubes), uterus, cervix, vagina, and vulva

What is the female gonad?

The ovary

What are the external genitalia of the female reproductive system?

Vulva and clitoris

What are the internal genitalia of the female reproductive system?

Ovaries, oviducts, uterus, cervix, and vagina

What are the 2 functions of the ovaries?

Gametogenesis (egg production) and endocrine function (hormone production)

What determines ovary shape?

Species and stage of the estrous cycle

What is polytocous?

A female that typically bears multiple offspring per pregnancy

What species are examples of polytocous animals?

Sow, bitch, and cat

What is the characteristic appearance of ovaries in polytocous animals?

Grape-like, due to multiple follicles or corpora lutea

What is monotocous?

A female that typically bears one offspring per pregnancy

What species are examples of monotocous animals?

Cow, ewe, and mare

What is the usual ovary shape in monotocous animals?

Usually ovoid, but the shape can change when a large follicle or corpus luteum (CL) is present

What is the unique shape of the mare ovary?

Kidney-shaped

Why is the mare ovary kidney-shaped?

Because it has an ovulation fossa

Where does ovulation normally occur in the mare?

At the ovulation fossa

What are the 3 layers of the ovary?

Germinal epithelium, tunica albuginea, and ovarian cortex

What is the germinal epithelium?

The outer covering of the ovary consisting of a single layer of cuboidal or low columnar cells

What is the tunica albuginea?

A layer of dense connective tissue beneath the germinal epithelium

What is the ovarian cortex?

The region containing ovarian follicles and serving as the site of follicular development

What are the morphologic classifications of ovarian follicles?

Primordial follicles, growing follicles, and Graafian follicles

What are the structural classifications of ovarian follicles?

Preantral and antral follicles

What is a preantral follicle?

A follicle with no antrum

What is an antral follicle?

A follicle with a fluid-filled antrum

What is folliculogenesis?

The formation and development of a primordial follicle into a mature (Graafian) follicle

When does folliculogenesis occur?

During the follicular phase

What are the characteristics of a primordial follicle?

It contains a primary oocyte, a single layer of flattened granulosa cells, and has no theca cells or blood vessels

When are primordial follicles present?

They are present at birth

Approximately how many follicles are found in a heifer ovary?

About 150,000 follicles

What happens to most primordial follicles?

Most remain dormant or undergo atresia

What are the characteristics of a growing follicle?

It has multiple granulosa cells, begins growth, has no antrum, and develops a theca layer as it grows

What develops around the oocyte during growing follicle development?

The zona pellucida

What are the other names for a Graafian follicle?

Tertiary follicle, mature follicle, and preovulatory follicle

What is the main characteristic of a Graafian follicle?

A large fluid-filled antrum

What is the function of a Graafian follicle?

It houses, nourishes, and ovulates the mature oocyte

What is follicular atresia?

The degeneration of ovarian follicles

When can follicular atresia occur?

At any stage of follicular development

What happens to most ovarian follicles?

Most never ovulate and undergo apoptosis

Which cells are most affected during follicular atresia?

Granulosa cells

Why is the ovarian follicle considered an endocrine organ?

Because it produces steroid hormones, peptide hormones, growth factors, and other signaling substances

What steroid hormones are produced by ovarian follicles?

Androgens and estrogens

What peptide hormone is produced by ovarian follicles?

Inhibin

What growth factor is produced by ovarian follicles?

IGF-1

What other substances can ovarian follicles produce?

Oocyte maturation inhibition factors, oxytocin in some species, gonadocrinin, activin, and follistatin

What determines follicular development?

Species genetics

How many follicles usually ovulate in monotocous animals?

Usually one follicle

What are examples of monotocous animals?

Cow, mare, and ewe

How many follicles usually ovulate in polytocous animals?

Usually several follicles

What are examples of polytocous animals?

Sow, bitch, and cat

What does estradiol do in follicular development?

It works with pituitary gonadotropins to help determine the number of follicles that ovulate

What is the main hormone controlling follicular growth?

FSH

What does FSH control?

Follicular growth and the number of follicles reaching ovulation

What is superovulation?

Administration of exogenous gonadotropins, especially FSH, to cause maturation of many follicles and multiple ovulations

What does superovulation cause?

Many follicles mature and multiple oocytes are ovulated

How many oocytes does a cow normally release?

Normally 1 oocyte

How many oocytes/embryos can a cow produce after superovulation?

Up to approximately 40 oocytes/embryos