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Menarche
First period between ages 9-14
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Menopause
45-55 years old when the menstrual cycle becomes infrequent and eventually stops
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What are the regions that make up an ovary
- Cortex
- Medulla
- Germinal epithelium
- Tunica albuginea
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What is the cortex of the ovary made up of
Ovarian follicles and corpus luteum
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What is the medulla of the ovary made up of
Loose connective tissue with blood vessels and lymphatics
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What is the Germinal epithelium of the ovary made up of
This covers the ovary, is derived from mesothelium, and composed of simple cuboidal cells
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What is the location and makeup of the Tunica Albuginea on the ovary
Made of dense connective tissue beneath the germinal epithelium
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Where do the primary oocytes originate
Wall of the yolk sac
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What does the corpus luteum become if not fertilized
Corpus albicans
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At birth, how many oocytes are within the primordial follicles
600,000 - 800,000
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What stage are the primary oocytes in at birth
Diplotene stage of Meiosis 1
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During a female lifetime, how many mature ovas does a female release
400
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Throught life what happens to most of the primary oocytes that were present at birth
They undergo atresia
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What are the three different types of ovarian follicles
- Primordial
- Growing (Primary & Secondary)
- Graafian follicles (mature)
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What are the physical characteristics of a Primordial follicle
- Large nucleus
- Balbiani body
- Annulate lamellae
- Surrounded by follicle cells
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Balbiani body
This is the congregating of ER, Golgi, Lysosomes, and Mitochondria on one side of the nucleus of the primary follicle
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Annulate Lamellae
Found in ooplasm of the primary follicle and resemble profiles of the nuclear envelope
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What are the different stages of primary follicles
- Primordial follicle
- Unilaminar
- Multilaminar
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What is the physical make up of a Unilaminar primary follicle
- Contains a primary oocyte and a single layer of simple cuboidal or columnar follicular cells resting on a basal lamina
- Surrounded by stromal cells (connective tissue)
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What is the physical makeup of Multilaminar primary follicle
- Follicular layer is stratified (granulosa layer)
- Contains an extracellular coat separating the granulosa layer from the oocyte called a Zona pellucida
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Multilaminar Primary oocytes secrete specific proteins that form what
An extracellular coat of glycoproteins called a Zona pellucida (ZP-1, ZP-2, ZP-3)
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What is the role of ZP-3, and where is it found
Found on the Multilaminar primary follicle and acts as a receptor for sperm binding and inducing acrosome reaction
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What is found surrounding the Multilaminar primary follicle just outside the Granulosa cells
Theca Folliculi (sheet of connective tissue)
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What makes up a Primordial follicle
The oocyte with a single layer of follicular cells surrounding it, and is imbedded in stromal cells
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Multilaminar Primary follicular cells are not dependent on
FSH for growth
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What happens to the Balbiani body during oocyte maturation
Organelles disperse and multiply in numbers
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Cortical granules
Located just beneath the plasma membrane of a developing primary follicle. These release proteolytic enzymes during fertilization
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What Follicle is first responsive to Follicle stimulating hormones (FSH)
Secondary follicle
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Granulosa cells contain what receptors
FSH
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What effect does FSH have on Granulosa cells
- It increases the number of granulosa cells and inter-cellular spaces
- Induces granulosa cells to make LH receptors
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What are the features of Secondary follicle cells
- Antrum (spaces between granulosa cells)
- Granulosa cells
- Theca interna
- Theca externa
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Theca interna contains what receptors, with what action
- Contain lots of LH receptors
- Produce Androgen in response to LH
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Theca interna
- Found in secondary follicles and Graafian follicles
- Inner layer of cuboidal cells
- Highly vascularized
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Theca externa
- Outer layer of connective tissue cells on the secondary follicle and Graafian follicle
- Made mainly of smooth muscle and collagen fibers
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Androgen released from the secondary follicles are precursors to
Estrogen
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What is the make up of a Graafian follicle
- Has a single antrum space
- Cumulus oophorus (attaches oocyte to granulosa cells)
- Corona radiata (surrounds the oocyte)
- Granulosa cells (inner wall lining)
- Theca interna (middle wall lining)
- Theca externa (outer wall lining)
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When does implantation occur
Around day 20
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How does LH effect the Secondary and Graafian stages
Stimulates theca interna cells to secrete androgen which is then transported to SER in granulosa cells
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What happens to Androgen after being transported to granulosa cells
They catalyze androgen to estradiol by the enzyme aromatase
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What are the effects of Estrogen on the other hormones 24 hrs before ovulation
- Negative feedback on FSH release from Pituitary
- LH surge (causing negative feedback)
- Negative feedback of LH causes estrogen to stop being produced by granulosa cells
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The LH surge has what effects on the oocyte
- Resuming meiosis 1
- Formation of secondary oocyte and 1st polar body
- Secondary oocyte is arrested in metaphase of meiosis 2
- Ovulation of secondary oocyte
- Formation of corpus luteum
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When does ovulation of the secondary oocyte occur
Day 14 of the 28 day cycle
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What is the region of the ovary called that is avascular, and is the sight of ovulation
Stigma
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Progesterone levels begin to rise when
Following ovulation, peaks around day 22, and digresses from there
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Corpus luteum is formed how
- Formed from the remnants of the Graafian follicle that ovulated
- Left over blood is removed by phagocytes
- LH change the structure as well
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Granulosa lutein cells are
- Modified granulosa cells in the corpus luteum, changed by presence of LH
- These make up 80% of the corpus luteum
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Theca lutein cells are modified
Theca interna cells, and make up 20% of the corpus luteum
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Granulosa Lutein cells produce
Mainly progesterone and some estrogens
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Theca lutein cells secrete
Progesterone and some estrogen
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What inhibits a second ovulation
Inhibition of FSH by the secretion of progesterone and estrogen from the corpus luteum
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What causes degeneration of the Corpus luteum forming the Corpus luteum of menstruation
The absence of LH when pregnancy does not occur
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What is released when pregnancy occurs
hCG secreted by syncytiotrophoblasts maintaining the viability of the corpus luteum
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Corpus luteum of pregnancy
Transformation of the corpus luteum via hCG, almost completely encompasses the ovary and continues to produce estrogen and progesterone for 3-4 months
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Progesterone inhibits
- LH
- "Pro-gressives stop looters"
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Estrogen inhibits
- FSH
- "Esther stops falling"
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Luteinizing hormone has what effect on ovulation
Induces ovulation and development of corpus luteum
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What induces theca interna cells to form LH receptors in secondary follicles
FSH
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What stimulates primary oocytes to complete meiosis 1
LH
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What causes ovulation of the secondary oocyte and formation of the corpus luteum
LH
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Graafian follicles produce large amounts of
Estradiol and inhibin which suppress FSH release from the pituitary
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