In Vitro Oogenesis - Revision history

Z8600021 at 00:05, 6 April 2020

2020-04-06T00:05:21Z

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	[[File:Frazer002_bw600.jpg\|thumb\|alt=Historic drawing comparing the size of the mature human oocyte with a spermatozoa\|Historic drawing comparing the size of the mature human oocyte with a spermatozoa]]		[[File:Frazer002_bw600.jpg\|thumb\|alt=Historic drawing comparing the size of the mature human oocyte with a spermatozoa\|Historic drawing comparing the size of the mature human oocyte with a spermatozoa]]

	In an adult human female, the in vivo ~~development~~ of a primordial follicle containing an oocyte to a preovulatory follicle takes in excess of 120 days.		In an adult human female, the development ''in vivo'' of a primordial follicle containing an oocyte to a preovulatory follicle takes in excess of 120 days.


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	Prior to release from the ovary oocytes (eggs, ova) are arrested at an early stage of the first meiotic division as a primary oocyte (primordial follicle). Following puberty, during each menstrual cycle, pituitary gonadotrophin stimulates completion of meiosis 1 the day before ovulation. Early oocytes are also classified as immature (germinal vesicle (GV) or metaphase I (MI) stage). The breakdown of the germinal vesicle indicates a resumption of meiosis and the extrusion of the first polar body (1 PB) indicates completion of the first meiotic division in human oocytes.		Prior to release from the ovary oocytes (eggs, ova) are arrested at an early stage of {{meiosis}} in the first meiotic division as a primary oocyte (primordial follicle). Following puberty, during each menstrual cycle, pituitary gonadotrophin stimulates completion of meiosis 1 the day before ovulation. Early oocytes are also classified as immature (germinal vesicle (GV) or metaphase I (MI) stage). The breakdown of the germinal vesicle indicates a resumption of meiosis and the extrusion of the first polar body (1 PB) indicates completion of the first meiotic division in human oocytes.

	The released oocyte is surrounded by a thick specialised extracellular matrix, the [[zona pellucida]], that in turn is covered in layers of cells, the [[granulosa cell~~\|granulosa~~ layer]].		The released oocyte is surrounded by a thick specialised extracellular matrix, the {{zona pellucida}}, that in turn is covered in layers of cells, the {{granulosa cell}} layer.


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	Search term: [http://www.ncbi.nlm.nih.gov/pubmed/?term=In+Vitro+Oogenesis ''In Vitro Oogenesis'']		Search term: [http://www.ncbi.nlm.nih.gov/pubmed/?term=In+Vitro+Oogenesis ''In Vitro Oogenesis'']

	~~<pubmed limit=5>In Vitro Oogenesis</pubmed>~~
	\|}		\|}

	{\|

	==Research==		==Research==

Z8600021 at 23:16, 21 March 2018

2018-03-21T23:16:25Z

← Older revision		Revision as of 10:16, 22 March 2018
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	In an adult human female, the in vivo development of a primordial follicle containing an oocyte to a preovulatory follicle takes in excess of 120 days.		In an adult human female, the in vivo development of a primordial follicle containing an oocyte to a preovulatory follicle takes in excess of 120 days.


			:''The Latin, ''In vitro'' = "in glass" meaning in essence a test tube as apposed to ''in vivo'' (in life or a living body)''


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	The released oocyte is surrounded by a thick specialised extracellular matrix, the [[zona pellucida]], that in turn is covered in layers of cells, the [[granulosa cell\|granulosa layer]].		The released oocyte is surrounded by a thick specialised extracellular matrix, the [[zona pellucida]], that in turn is covered in layers of cells, the [[granulosa cell\|granulosa layer]].


	~~:''The Latin, ''In vitro'' = "in glass" meaning in essence a test tube as apposed to ''in vivo'' (in life or a living body)''~~

	{{ART Links}}		{{ART Links}}


	== Some Recent Findings ==		== Some Recent Findings ==

Z8600021 at 23:13, 21 March 2018

2018-03-21T23:13:03Z

← Older revision		Revision as of 10:13, 22 March 2018
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	:"The cyclic nucleotides, cAMP and cGMP, are the key molecules controlling mammalian oocyte meiosis. Their roles in oocyte biology have been at the forefront of oocyte research for decades and many of the long standing controversies in relation to the regulation of oocyte meiotic maturation are now resolved. It is now clear that the follicle prevents meiotic resumption through the actions of natriuretic peptides and cGMP inhibiting the hydrolysis of intra-oocyte cAMP and that the preovulatory gonadotrophin surge reverses these processes. The gonadotrophin surge also leads to a transient spike in cAMP in the somatic compartment of the follicle; research over the past 2 decades has conclusively demonstrated that this surge in cAMP is important for the subsequent developmental capacity of the oocyte. This is important, as oocyte in vitro maturation (IVM) systems practiced clinically do not recapitulate this cAMP surge in vitro, possibly accounting for the lower efficiency of IVM compared to clinical IVF. This review focuses in particular on this latter aspect - the role of cAMP/cGMP in the regulation of oocyte quality. We conclude that clinical practice of IVM should reflect this new understanding of the role of cyclic nucleotides, thereby creating a new generation of ART and fertility treatment options."{{#pmid:27422885\|PMID27422885}}		:"The cyclic nucleotides, cAMP and cGMP, are the key molecules controlling mammalian oocyte meiosis. Their roles in oocyte biology have been at the forefront of oocyte research for decades and many of the long standing controversies in relation to the regulation of oocyte meiotic maturation are now resolved. It is now clear that the follicle prevents meiotic resumption through the actions of natriuretic peptides and cGMP inhibiting the hydrolysis of intra-oocyte cAMP and that the preovulatory gonadotrophin surge reverses these processes. The gonadotrophin surge also leads to a transient spike in cAMP in the somatic compartment of the follicle; research over the past 2 decades has conclusively demonstrated that this surge in cAMP is important for the subsequent developmental capacity of the oocyte. This is important, as oocyte in vitro maturation (IVM) systems practiced clinically do not recapitulate this cAMP surge in vitro, possibly accounting for the lower efficiency of IVM compared to clinical IVF. This review focuses in particular on this latter aspect - the role of cAMP/cGMP in the regulation of oocyte quality. We conclude that clinical practice of IVM should reflect this new understanding of the role of cyclic nucleotides, thereby creating a new generation of ART and fertility treatment options."{{#pmid:27422885\|PMID27422885}}


			:'''Links:''' [[ANAT2341 Lab 4]]

	==In Vivo Oogenesis==		==In Vivo Oogenesis==

Z8600021 at 23:12, 21 March 2018

2018-03-21T23:12:26Z

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 |}
-== In Vivo Oogenesis ==
+{|
 [[File:Ovary histology 061.jpg|thumb|alt=Secondary follicle with oocyte|Secondary follicle with oocyte.]]
 A human infant ovary histology, showing the large number of oocytes occupying the ovary cortical region. Compare this with a mature ovary and note the absence of any follicle development in the infant. These early oocytes remain at the diplotene stage of the meiosis I during development from fetal life and postnatal childhood, until puberty when the lutenizing hormone (LH) surges stimulate the resumption of meiosis.

Z8600021 at 23:08, 21 March 2018

2018-03-21T23:08:08Z

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 [[File:Frazer002_bw600.jpg|thumb|alt=Historic drawing comparing the size of the mature human oocyte with a spermatozoa|Historic drawing comparing the size of the mature human oocyte with a spermatozoa]]
 Prior to release from the ovary oocytes (eggs, ova) are arrested at an early stage of the first meiotic division as a primary oocyte (primordial follicle). Following puberty, during each menstrual cycle, pituitary gonadotrophin stimulates completion of meiosis 1 the day before ovulation. Early oocytes are also classified as immature (germinal vesicle (GV) or metaphase I (MI) stage). The breakdown of the germinal vesicle indicates a resumption of meiosis and the extrusion of the first polar body (1 PB) indicates completion of the first meiotic division in human oocytes.
@@ Line 9: / Line 12: @@
-:''In an adult human female, the development of a primordial follicle containing an oocyte to a preovulatory follicle takes in excess of 120 days.''
+:''The Latin, ''In vitro'' = "in glass" meaning in essence a test tube as apposed to ''in vivo'' (in life or a living body)''
 {{ART Links}}
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 :'''Links:''' [[Cell_Division_-_Meiosis|Meiosis]]
 ==Cortical Granules==
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 * cumulus expansion and granulosa cell differentiation are dependent upon oocyte-derived factors
 * BMP15 inhibits FSH-stimulated progesterone production
 ==Oocyte Metabolism==

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2018-03-21T23:05:54Z

Created page with "{{Header}}right ==Introduction== File:Frazer002_bw600.jpg|thumb|alt=Historic drawing comparing the size of the mature human oocyte with a spermato..."

New page

{{Header}}[[File:Human-oocyte.jpg|right]]
==Introduction==

[[File:Frazer002_bw600.jpg|thumb|alt=Historic drawing comparing the size of the mature human oocyte with a spermatozoa|Historic drawing comparing the size of the mature human oocyte with a spermatozoa]]

Prior to release from the ovary oocytes (eggs, ova) are arrested at an early stage of the first meiotic division as a primary oocyte (primordial follicle). Following puberty, during each menstrual cycle, pituitary gonadotrophin stimulates completion of meiosis 1 the day before ovulation. Early oocytes are also classified as immature (germinal vesicle (GV) or metaphase I (MI) stage). The breakdown of the germinal vesicle indicates a resumption of meiosis and the extrusion of the first polar body (1 PB) indicates completion of the first meiotic division in human oocytes.

The released oocyte is surrounded by a thick specialised extracellular matrix, the [[zona pellucida]], that in turn is covered in layers of cells, the [[granulosa cell|granulosa layer]].

:''In an adult human female, the development of a primordial follicle containing an oocyte to a preovulatory follicle takes in excess of 120 days.''

{{ART Links}}

== Some Recent Findings ==
{|
|-bgcolor="F5FAFF"
|
* '''Complete in vitro oogenesis: retrospects and prospects'''{{#pmid:28841213|PMID28841213}} "In reality the vast majority of oocytes formed from primordial germ cells (PGCs) will undergo apoptosis, or other forms of cell death. Removal occurs during germ cell cyst breakdown and the establishment of the primordial follicle (PF) pool, during the long dormancy at the PF stage, or through follicular atresia prior to reaching the ovulatory stage. A way to solve this limitation could be to produce large numbers of oocytes, in vitro, from stem cells. However, to recapitulate mammalian oogenesis and produce fertilizable oocytes in vitro is a complex process involving several different cell types, precise follicular cell-oocyte reciprocal interactions, a variety of nutrients and combinations of cytokines, and precise growth factors and hormones depending on the developmental stage. In 2016, two papers published by Morohaku et al. and Hikabe et al. reported in vitro procedures that appear to reproduce efficiently these conditions allowing for the production, completely in a dish, of a relatively large number of oocytes that are fertilizable and capable of giving rise to viable offspring in the mouse. The present article offers a critical overview of these results as well as other previous work performed mainly in mouse attempting to reproduce oogenesis completely in vitro and considers some perspectives for the potential to adapt the methods to produce functional human oocytes."

* '''Oocyte formation by mitotically active germ cells purified from ovaries of reproductive-age women'''{{#pmid:22366948|PMID22366948}} "Germline stem cells that produce oocytes in vitro and fertilization-competent eggs in vivo have been identified in and isolated from adult mouse ovaries. Here we describe and validate a fluorescence-activated cell sorting-based protocol that can be used with adult mouse ovaries and human ovarian cortical tissue to purify rare mitotically active cells that have a gene expression profile that is consistent with primitive germ cells. Once established in vitro, these cells can be expanded for months and can spontaneously generate 35- to 50-μm oocytes, as determined by morphology, gene expression and haploid (1n) status. Injection of the human germline cells, engineered to stably express GFP, into human ovarian cortical biopsies leads to formation of follicles containing GFP-positive oocytes 1-2 weeks after xenotransplantation into immunodeficient female mice. Thus, ovaries of reproductive-age women, similar to adult mice, possess rare mitotically active germ cells that can be propagated in vitro as well as generate oocytes in vitro and in vivo." (these cells described as oogonial stem cells (OSCs), are very rare—only about 1 out of 10,000 ovarian cells)
|}
{| class="wikitable mw-collapsible mw-collapsed"
! More recent papers  
|-
| [[File:Mark_Hill.jpg|90px|left]] {{Most_Recent_Refs}}

Search term: [http://www.ncbi.nlm.nih.gov/pubmed/?term=In+Vitro+Oogenesis ''In Vitro Oogenesis'']

<pubmed limit=5>In Vitro Oogenesis</pubmed>
|}

== In Vivo Oogenesis ==
[[File:Ovary histology 061.jpg|thumb|alt=Secondary follicle with oocyte|Secondary follicle with oocyte.]]
A human infant ovary histology, showing the large number of oocytes occupying the ovary cortical region. Compare this with a mature ovary and note the absence of any follicle development in the infant. These early oocytes remain at the diplotene stage of the meiosis I during development from fetal life and postnatal childhood, until puberty when the lutenizing hormone (LH) surges stimulate the resumption of meiosis.

[[File:Infant_ovary.jpg|500px]]

The graph below shows the changes in human [[G#germ cell|germ cell]] numbers in the ovary with age, peaking at about 7 million (occuring in early fetal development) and then decreasing by [[A#apoptosis|apopotic cell death]]. At [[P#puberty|puberty]] there remain only about 400,000 and only about 10% of these will be released through reproductive life. (More? [[Menstrual Cycle]])

[[File:Human_ovary_non-growing_follicle_model.jpg|alt=Human ovary non-growing follicle model|600px]]

Human ovary non-growing follicle model{{#pmid:20111701|PMID20111701}}

:'''Links:''' [[Ovary Development]] | [[Assisted Reproductive Technology]]

==Oocyte Growth==

[[File:Ovary oocyte size graph.jpg|alt=Ovary oocyte size graph|600px]]

Graph shows species comparison in oocyte size growth (diameter) at different stages of follicle development.{{#pmid:16509981|PMID16509981}} (See also [[:File:Ovary follicle size graph.jpg|Follicle size graph]])

{{Follicle class collapse table}}
==Meiosis ==
[[File:Hamilton1944-fig05.jpg|thumb|alt=Human Oocyte metaphase of meiosis 2|Human Oocyte metaphase of meiosis 2]]
In females, the total number of eggs ever to be produced are present in the newborn female initially arrested at the diplotene stage of the meiosis I from fetal life through childhood until puberty, when the lutenizing hormone (LH) surges stimulate the resumption of meiosis.

# All eggs are arrested at an early stage (prophase I) of the first meiotic division as a primary oocyte (primordial follicle). Following purberty, during each menstrual cycle, pituitary gonadotrophin stimulates completion of '''meiosis 1''' the day before ovulation.
# In '''meiosis 1''', a diploid cell becomes 2 haploid (23 chromosomes) daughter cells, each chromosome has two chromatids. One cell becomes the secondary oocyte the other cell forms the first polar body.
# The secondary oocyte then commences '''meiosis 2''' which arrests at metaphase and will not continue without fertilization.
# At fertilization '''meiosis 2''' completes, forming a second polar body. Note that the first polar body may also undergo this process forming a third polar body.

[[File:Female_gametogenesis.jpg|600px|alt=Female gametogenesis|Female gametogenesis]]

:'''Links:''' [[Cell Division - Meiosis]]
==Polar Body==
[[File:Human oocyte-metaphase II.jpg|thumb|Human oocyte at metaphase II showing polar body at top]]
The breakdown of the germinal vesicle indicates a resumption of meiosis and the extrusion of the first polar body (1 PB) indicates completion of the first meiotic division in human oocytes. The polar body is a small cytoplasmic exclusion body formed to enclose the excess DNA formed during the oocyte (egg) meiosis and following sperm fertilization. There are 2-3 polar bodies derived from the oocyte present in the zygote, the number is dependent upon whether polar body 1 (the first polar body formed during meiosis 1) divides during meiosis 2. This exclusion body contains the excess DNA from the reductive division (the second and third polar bodies are formed from meiosis 2 at fertilization). These polar bodies do not contribute to the future genetic complement of the zygote, embryo or fetus.

Recent research in some species suggest that the space formed by the peripheral polar body (between the oocyte and the zona pellucia) can influence the site of spermatozoa fertilization.

===Polar Body Extrusion Model===

The following cartoon model from mouse oocyte study of polar body extrusion, involving cortical cap protrusion and spindle midzone-induced membrane furrowing.{{#pmid:21867530|PMID21867530}}
{| width=600px
| colspan=5|[[File:Polar body extrusion model.jpg|alt=Polar body extrusion model|600px]]
|-
| width=120px valign=top|(A) Chromosomes induce formation of a cortical actomyosin cap/ring prior to polar body extrusion.
| width=120px valign=top|(B) Egg activation induces the cortical cap protrusion.
| width=120px valign=top|(C) The anaphase spindle midzone induces unilateral furrowing.
| width=120px valign=top|(D) Spindle rotation.
| width=120px valign=top|(E) Spindle midzone induces bilateral furrowing and abscission of polar body.
|-
| colspan=5|The squared region of the cortical cap/ring is shown on the top, an actin cap (red) surrounded by a myosin II ring (green).
|}

Assisted reproductive techniques involving intracytoplasmic sperm injection (ICSI) have looked at the "quality" of the polar body and found that the morphology is related to mature oocyte viability and has the potential to predict oocyte fertilization rates and pregnancy achievement.{{#pmid:10655316|PMID10655316}}{{#pmid:19960239|PMID19960239}}

:'''Links:''' [[Cell_Division_-_Meiosis|Meiosis]]

==Calcium Release==
Oocyte calcium ion (Ca<sup>2+</sup>) release occurs after spermatozoa fusion and is part of the reactivation of meiosis (arrested at metaphase II) and the primary block to polyspermy. Earlier in oocyte meiosis, between prophase I (germinal vesicle stage) and MII, this release mechanism is developed within the cell.

Oocyte cytoplasmic changes include:
# endoplasmatic reticulum reorganization.
# IP3 receptor increase in both number and sensitivity.
# increase in calcium ion concentration.

==Cortical Granules==
[[File:Human_MII_oocyte_02.jpg|thumb|alt=Human oocyte (MII) showing cortical granules|Human oocyte (MII) showing cortical granules (green)]]
[[File:Mouse oocyte cortical granules 01.jpg|thumb|alt=Mouse oocyte cortical granules|Mouse oocyte cortical granules (red)]]
The release of cortical granules by exocytosis, the "cortical reaction", occurs following spermatozoa fertilisation and is the main block to polyspermy by modifying the zone pellucida. These granules develop from the golgi apparatus initially forming smaller vesicles that coalesce to form mature membrane bound cortical granules (0.2 to 0.6 microns in diameter) located in the cortex of unfertilized oocytes. In mammals, cortical granule production in the developing follicular oocyte is an ongoing and continuous process, with newly synthesized granules translocating to the cortex until the time of ovulation.

Cortical granules:
* vary in time of initial development between species.
** primordial follicle stage - rat and mouse.
** primary follicle stage - human, monkey, hamsters, and rabbit.
* vary in type formed in the same species.
* migration requires the microfilaments of the cell cytoskeleton.
* are evenly distributed in the cortex of unfertilised oocytes.
* contain carbohydrates, proteinases, ovoperoxidase, calreticulin, N-acetylglucosaminidase

===Ovastacin===
* oocyte-specific member of the astacin family
* mouse cortical granule protease (metalloendoproteases)
* cleaves zona pellucida ZP2
* female mice lacking ovastacin do not cleave ZP2 after fertilisation{{#pmid:22472438|PMID22472438}}

==Oocyte-Follicle Cell Interaction==

The oocyte and the surrounding granulosa cells have a complex paracrine interactions during follicle growth and development. Oocyte maturation has been shown to depend on secretory products of both the granulosa and cumulus cells.

===Oocyte Factors===
* promotes granulosa cell proliferation in preantral and antral follicles (GDF-9, BMP15)
* cumulus expansion and granulosa cell differentiation are dependent upon oocyte-derived factors
* BMP15 inhibits FSH-stimulated progesterone production

==Oocyte Different Species==

{{Hartman1929 collapsible table8}}

<gallery>
File:Ovary- histology secondary follicle 01.jpg|Monkey antral follicle
File:Mouse follicle in vitro.jpg|Mouse
File:Mouse oocyte and zona pellucida EM01.jpg|Mouse oocyte and zona pellucida EM
File:Mouse- zona pellucida 02.jpg|Mouse
File:Canine_oocyte_04.jpg|Canine (dog)
File:Canine_oocyte_02.jpg|Canine (dog)
File:Salamander-oocyte.jpg|Salamander
File:Sheep oocyte 01.jpg|Sheep
File:Sheep oocyte 02.jpg|Sheep
File:Sheep oocyte 03.jpg|Sheep
File:Sheep oocyte 04.jpg|Sheep
</gallery>

==Oocyte Metabolism==
[[File:SIRT1 cell distribution.jpg|thumb|alt=SIRT1 cell distribution|SIRT1 cell distribution.{{#pmid:27791113|PMID27791113}}]]
In the mouse, the secondary follicle stage through to large antral follicle stage the oocyte has a highly oxidative metabolism. In contrast, the surrounding surrounding granulosa and cumulus cells are highly glycolytic. In this second group, the cumulus cells are found to be more glycolytic than the granulosa cells.{{#pmid:27683265|PMID27683265}}

* oxidative metabolism - requires oxygen (aerobic) to make energy from carbohydrates (sugars) into pyruvate that passes into the mitochondria where it is fully oxidised by oxygen into carbon dioxide. Also called aerobic metabolism, aerobic respiration, and cell respiration.
* glycolytic metabolism - requires no oxygen (anaerobic) to make energy from carbohydrates (sugars) into pyruvate that is reduced by adenine dinucleotide hydride (NADH).

In the cat oocyte, in pre-antral oocytes mitochondria have a homogeneous distribution throughout the cytoplasm. In the antral stage they have relocated to a mainly pericortical distribution.{{#pmid:28111812|PMID28111812}}

:'''Links:''' [https://www.omim.org/entry/604479 OMIM SIRT1]
==Oocyte Protein Expression==

[[File:Mouse- germinal vesicle oocyte protein expression.jpg|alt=Mouse- germinal vesicle oocyte protein expression]]

[[File:Mouse- MII oocyte protein expression.jpg|alt=Mouse- MII oocyte protein expression]]

The table above shows the pattern of protein expression (as percentages of total) in the mouse germinal vesicle and MII oocyte according to 14 molecular function categories.{{#pmid:20876089|PMID20876089}}

:'''Links:''' [[:File:Mouse- germinal vesicle oocyte protein expression.jpg|Germinal vesicle oocyte protein expression]] | [[:File:Mouse-_MII_oocyte_protein_expression.jpg|MII oocyte protein expression]] | [[:File:Mouse- zygote protein expression.jpg|Zygote Protein Expression]] | [[Mouse Development]] | [[Oocyte Development]] | [[Zygote]]

===Oocyte Telomerase Reverse Transcriptase===

There is a redistribution of the enzyme that regulates telomere length during oocyte development. The following oocyte images are from a recent study of sheep ''in vitro'' follicle development.{{#pmid:22132111|PMID22132111}}
{|
| [[File:Sheep oocyte 01.jpg|alt=Sheep oocyte image|250px]]
| [[File:Sheep oocyte 02.jpg|alt=Sheep oocyte image|250px]]
|-
| preantral
| early antral
|-
| [[File:Sheep oocyte 03.jpg|alt=Sheep oocyte image|250px]]
| [[File:Sheep oocyte 04.jpg|alt=Sheep oocyte image|250px]]
|-
| early antral
| preovulatory follicle
|}

{{Sheep_Oocyte_TERT}}

==Abnormalities==
[[File:Trisomy21female.jpg|thumb|Trisomy 21 female karyotype]]
Meiotic non-disjunction resulting in aneuploidy, most are embryonic lethal and not seen. The potential for genetic abnormalities increase with maternal age.

{|
|-
! Autosomal chromosome aneuploidy
! Sex chromosome aneuploidy
|-
|
* '''trisomy 21''' - [[trisomy 21|Down syndrome]]
* '''trisomy 18''' - [[Trisomy 18|Edwards syndrome]]
* '''trisomy 13''' - [[Trisomy 13|Patau syndrome]]
|
* monosomy X - Turner's Syndrome
* '''trisomy X''' - [[Trisomy X|Triple-X syndrome]]
* 47 XXY - Klinefelter's Syndrome
|}

:'''Links:''' [[Trisomy 21]] | [[Abnormal Development - Genetic]] | [[Genital System - Abnormalities]]
==Additional Images==

<gallery>

</gallery>

==References==

<references/>

===Reviews===
{{#pmid:23429793}}

{{#pmid:22088197}}

===Articles===

===Search ===

* '''NCBI Bookshelf''' [http://www.ncbi.nlm.nih.gov/sites/entrez?db=Books&cmd=search&term=oocyte oocyte] | [http://www.ncbi.nlm.nih.gov/sites/entrez?db=Books&cmd=search&term=oogenesis oogenesis] | [http://www.ncbi.nlm.nih.gov/sites/entrez?db=Books&cmd=search&term=oocyte+development oocyte development]

* '''Pubmed''' [http://www.ncbi.nlm.nih.gov/sites/gquery?itool=toolbar&cmd=search&term=oocyte oocyte] | [http://www.ncbi.nlm.nih.gov/sites/gquery?itool=toolbar&cmd=search&term=oogenesis oogenesis] | [http://www.ncbi.nlm.nih.gov/sites/gquery?itool=toolbar&cmd=search&term=oocyte+development oocyte development]

{{Glossary}}

==Terms==

{{Oocyte terms}}

{{Glossary}}

{{Footer}}
[[Category:Assisted Reproductive Technology]]
[[Category:Oocyte]] [[Category:Human Embryo]] [[Category:Week 1]]