Ovum

WikiDoc Resources for Ovum
Articles
Most recent articles on Ovum Most cited articles on Ovum Review articles on Ovum Articles on Ovum in N Eng J Med, Lancet, BMJ
Media
Powerpoint slides on Ovum Images of Ovum Photos of Ovum Podcasts & MP3s on Ovum Videos on Ovum
Evidence Based Medicine
Cochrane Collaboration on Ovum Bandolier on Ovum TRIP on Ovum
Clinical Trials
Ongoing Trials on Ovum at Clinical Trials.gov Trial results on Ovum Clinical Trials on Ovum at Google
Guidelines / Policies / Govt
US National Guidelines Clearinghouse on Ovum NICE Guidance on Ovum NHS PRODIGY Guidance FDA on Ovum CDC on Ovum
Books
Books on Ovum
News
Ovum in the news Be alerted to news on Ovum News trends on Ovum
Commentary
Blogs on Ovum
Definitions
Definitions of Ovum
Patient Resources / Community
Patient resources on Ovum Discussion groups on Ovum Patient Handouts on Ovum Directions to Hospitals Treating Ovum Risk calculators and risk factors for Ovum
Healthcare Provider Resources
Symptoms of Ovum Causes & Risk Factors for Ovum Diagnostic studies for Ovum Treatment of Ovum
Continuing Medical Education (CME)
CME Programs on Ovum
International
Ovum en Espanol Ovum en Francais
Business
Ovum in the Marketplace Patents on Ovum
Experimental / Informatics
List of terms related to Ovum

Please Take Over This Page and Apply to be Editor-In-Chief for this topic: There can be one or more than one Editor-In-Chief. You may also apply to be an Associate Editor-In-Chief of one of the subtopics below. Please mail us [1] to indicate your interest in serving either as an Editor-In-Chief of the entire topic or as an Associate Editor-In-Chief for a subtopic. Please be sure to attach your CV and or biographical sketch.

Overview

A human ovum

Sperm cells attempting to fertilize an ovum

An ovum (plural ova) is a haploid female reproductive cell or gamete. The word is derived from Latin, meaning egg or egg cell. Both animals and embryophytes have ova. The term ovule is used for the young ovum of an animal, as well as the plant structure that carries the female gametophyte and egg cell and develops into a seed after fertilization. In some plants, such as algae, it is also called oosphere.

Material contribution to offspring

The egg is the sole provider of such endosymbiotic organelles, including mitochondria within the cytoplasm. These cannot be produced with nuclear DNA alone and must be manufactured from DNA within existing organelles of their type (such as mitochondrial DNA) — this is important in Human mitochondrial genetics and can be used to trace maternal and paternal ancestry, especially as plants contain chloroplasts as well. Sperm are often too small to contribute anything physical except DNA and its own mitochondria gets destroyed by the egg.

Ova production

In higher animals, ova are produced by female gonads (sexual glands) called ovaries and all of them are present at birth in mammals, and mature via oogenesis.

Human and mammal ova

A sperm cell fusing with an ovum

In the viviparous animals (which include humans and all other placental mammals), the ovum is fertilized inside the female body, and the embryo then develops inside the uterus, receiving nutrition directly from the mother. The ovum is the largest cell in the human body, typically visible to the naked eye without the aid of a microscope or other magnification device. The human ovum measures on average, 145 µm in diameter.

Protist and plant ova

In protists, fungi and many plants, such as bryophytes, ferns, and gymnosperms, ova are produced inside archegonia. Since the archegonium is a haploid structure, egg cells are produced via mitosis. The typical bryophyte archegonium consists of a long neck with a wider base containing the egg cell. Upon maturation, the neck opens to allow sperm cells to swim into the archegonium and fertilize the egg. The resulting zygote then gives rise to an embryo, which will grow out of the archegonium as a sporeling (young sporophyte).

In the flowering plants, the female gametophyte, which usually gives rise to the archegonium, has been reduced to just eight cells referred to as the embryo sac inside the ovule. The gametophyte cell closest to the micropyle opening of the embryo sac develops into the egg cell. Upon pollination, a pollen tube delivers sperm into the embryo sac and one sperm nucleus fuses with the egg nucleus. The resulting zygote develops into an embryo inside the ovule. The ovule in turn develops into a seed and in many cases the plant ovary develops into a fruit to facilitate the dispersal of the seeds. Upon germination, the embryo grows into a seedling.

Ova development in oviparous animals

In the oviparous animals (all birds, most fishes, amphibians and reptiles) the ova develop protective layers and pass through the oviduct to the outside of the body. They are fertilized by male sperm either inside the female body (as in birds), or outside (as in many fishes). After fertilization, an embryo develops, nourished by nutrients contained in the egg. It then hatches from the egg, outside the mother's body. See egg (biology) for a discussion of eggs of oviparous animals.

The egg cell's cytoplasm and mitochondria (and chloroplasts in plants) are the sole means of the egg being able to reproduce by mitosis and eventually form a blastocyst after fertilization.

Ovoviviparity

There is an intermediate form, the ovoviviparous animals: the embryo develops within and is nourished by an egg as in the oviparous case, but then it hatches inside the mother's body shortly before birth, or just after the egg leaves the mother's body. Some fish, reptiles and many invertebrates use this technique.

See also

• Egg (biology)
• Fertilisation
• Insemination
• Menstrual cycle
• Ovulation
• Pollination
• Pregnancy
• Respiratory burst
• Sperm
• Zygote
• Male egg

External links

• The Ovarian Kaleidoscope Database description of 1800 genes involved in ovarian functions

Cost Effectiveness of Ovum

| group5 = Clinical Trials Involving Ovum | list5 = Ongoing Trials on Ovum at Clinical Trials.gov • Trial results on Ovum • Clinical Trials on Ovum at Google

| group6 = Guidelines / Policies / Government Resources (FDA/CDC) Regarding Ovum | list6 = US National Guidelines Clearinghouse on Ovum • NICE Guidance on Ovum • NHS PRODIGY Guidance • FDA on Ovum • CDC on Ovum

| group7 = Textbook Information on Ovum | list7 = Books and Textbook Information on Ovum

| group8 = Pharmacology Resources on Ovum | list8 = AND (Dose)}} Dosing of Ovum • AND (drug interactions)}} Drug interactions with Ovum • AND (side effects)}} Side effects of Ovum • AND (Allergy)}} Allergic reactions to Ovum • AND (overdose)}} Overdose information on Ovum • AND (carcinogenicity)}} Carcinogenicity information on Ovum • AND (pregnancy)}} Ovum in pregnancy • AND (pharmacokinetics)}} Pharmacokinetics of Ovum •

| group9 = Genetics, Pharmacogenomics, and Proteinomics of Ovum | list9 = AND (pharmacogenomics)}} Genetics of Ovum • AND (pharmacogenomics)}} Pharmacogenomics of Ovum • AND (proteomics)}} Proteomics of Ovum

| group10 = Newstories on Ovum | list10 = Ovum in the news • Be alerted to news on Ovum • News trends on Ovum</small>

| group11 = Commentary on Ovum | list11 = Blogs on Ovum

| group12 = Patient Resources on Ovum | list12 = Patient resources on Ovum • Discussion groups on Ovum • Patient Handouts on Ovum • Directions to Hospitals Treating Ovum • Risk calculators and risk factors for Ovum

| group13 = Healthcare Provider Resources on Ovum | list13 = Symptoms of Ovum • Causes & Risk Factors for Ovum • Diagnostic studies for Ovum • Treatment of Ovum

| group14 = Continuing Medical Education (CME) Programs on Ovum | list14 = CME Programs on Ovum

| group15 = International Resources on Ovum | list15 = Ovum en Espanol • Ovum en Francais

| group16 = Business Resources on Ovum | list16 = Ovum in the Marketplace • Patents on Ovum

| group17 = Informatics Resources on Ovum | list17 = List of terms related to Ovum

}}ar:بييضة bs:Jajna ćelija bg:Яйцеклетка ca:Òvul da:Æg (fysiologi) de:Eizelleko:난자 id:Sel telur he:ביצית lt:Kiaušialąstė mk:Јајце клетка nl:Eicelno:Eggcelle oc:Ovulsk:Vajíčko (bunka) sr:Јајна ћелија sh:Jajna ćelija su:Ovum fi:Munasolu ta:கருமுட்டைuk:Яйцеклітина yi:איי