6 – Female Reproduction I Flashcards
1
Q
Ovary function
A
- Development of female gamete (oocyte) for fertilization
- Produce and secret sex steroid hormones to regulate reproductive health
2
Q
Ovary divided into 2 distinct regions
A
- Outer cortex
o Ovarian follicles - Inner medulla
o Blood vessels
o Nerves
o Connective tissue - *opposite orientation in mares but contents are the same
3
Q
Folliculogenesis
A
- Development of ovarian follicles from immature to mature form
4
Q
2 stages of folliculogenesis
A
- Resting phase: primordial follicles
- Growth phase
4
Q
Folliculognesis stages
A
- Primordial
- Primary
- Early secondary
- Secondary
- Antral (early and late)
- Preovulatory
o Ovulation OR follicular death by atresia
5
Q
Primordial follicles
A
- Specific number at birth
- Primary oocyte surrounded by a single layer of flat follicular cells
6
Q
Ruminant primordial follicle
A
- Equally distributed in cortex
7
Q
Carnivores primordial follicle
A
- In clusters in the cortex
8
Q
Bipotential gonad
A
- Development of a testis OR ovary
9
Q
3 cell populations during gonad transformation to ovaries
A
- Granulosa cells
- Theca cells
- Primordial germ cells
*3 components of the follicle
10
Q
Granulosa cells
A
- Supporting cells
- Subtype of somatic cells
11
Q
Theca cells
A
- Steroidogenic cell precursors
- Subtype of somatic cells
12
Q
Primordial germ cells
A
- Become oocytes through the OOGENESIS
13
Q
Where does the ovary development commence?
A
- Mesonephric surface epithelium in location of future gonadal ridge
14
Q
Primary follicle
A
- When epithelium around primary oocyte becomes cuboidal
15
Q
Secondary follicle
A
- 2-6 layers of granulosa cells
- Theca cells
- Zona pellucida material
16
Q
Theca cells
A
- Typical steroid-producing cells
- Additional somatic cell layer
17
Q
Zona pellucida
A
- Glycoprotein layer secreted by the oocyte and granulosa cells
18
Q
Tertiary (antral) follicle
A
- More than 6 layers of granulosa cells
- Have an antrum
- Fully developed ZP
- External and internal theca cell layers
- Start of cumulus cell formation
19
Q
Antrum
A
- Fluid (follicular)-filled cavity
- Fluid comes from granulosa and theca cells
20
Q
Graafian follicles (pre-ovulatory)
A
- Most mature of antral follicles (still is an antral follicle)
- Granulosa cells produce estradiol
- Internal theca=vascular
- External theca=connective tissue
21
Q
Graafian follicles: zona pellucida
A
- Surrounds oocyte
- Located between oocyte and follicular cells
22
Q
Graafian follicles: corona radiata
A
- First layer of follicular (granulosa) cells outside the ZP
23
Q
Graafian follicles: cumulus oophorus
A
- ‘egg-bearing’ heap
- Thickened mound of granulosa cells that surround oocyte and projects into antrum
24
Graafian follicles: membrane granulosa
* Layer of granulosa cells bordering the antrum
25
Graafian follicles: theca interna
* Endocrine-like
* Border the membrane granulosa
26
Graafian follicles: theca externa
* Fibroblast-resembling cells just outside theca interna
* Exterior limits of it are NOT discernible
27
Atretic (regressing) follicles
* Can occur at any follicular phase
* ACTIVE cellular process with resorption of follicle
* NOT all Graafian follicles ovulate
28
ACTIVE cellular process with resorption of follicle involving
* Macrophage infiltration
* Phagocytosis
* Migration of fibroblasts from theca
* Production of collagen
29
2 different types of ovulation
* Spontaneous: most domestic animals=NEED external stimuli to ovulate
* Induced: queen, camelids, rabbit
30
What happens near ovulation?
* Blood supply increases
* Follicular wall becomes thin and transparent near future site of ovulation
31
Size of preovulatory follicles: mare
* 50-70mm
32
Size of preovulatory follicles: cow
* 13-16mm
33
Size of preovulatory follicles: ewe, goat, sow
* 8-10mm
34
Size of preovulatory follicles: dog and queen
* 2mm
35
Stigma
* Site where follicle ovulates
36
Oocyte development
* PGCs at gonadal ridges differentiate into oogonia
* Oogonia enter meiosis I (primary oocytes)
* Primary oocytes initiate meiosis but are arrested in diplotene stage or prophase I
* Primary oocyte completes first meiotic division immediately before ovulation to form secondary oocyte and first polar body
* First division completed shortly after ovulation in dog and mare
37
Corpus luteum (CL)
* Transient endocrine gland
* Develops from a Graafian follicle after ovulation
* Required to support pregnancy in mammals
o Produces progesterone
38
Corpus hemorrhagicum
* When ovulation of Graafian follicle has occurred=blood derived from torn blood vesicles of the theca layer infiltrates the collapse follicle
* Developing CL with a bloody core
39
CL: remaining granulosa cells and cells of theca interna undergo
* Hypertrophy, proliferate and invade corpus hemorrhagicum
* Transforms into granulosa lutein cells and theca lutein cells =CL
o Yellow due to lutein or other lipid pigments
40
CL in cows
* Fully developed by 9days after ovulation
* Continues to grow till 12 days
* Regresses in late diestrus
41
What happens to CL when pregnancy does NOT occur?
* CL degenerates after a certain length of time (species dependant)
* Condensation of lutein pigment and degeneration of luteal cells
* Becomes corpus albicans
42
Corpus albicans
* Connective tissue that replaces the luteal cells from the regressed CL
* *WHITE
