Ovum

From Wikipedia, the free encyclopedia

An ovum (Latin: "egg", Plural: Ova) is the name for the haploid female reproductive cell.

Haploid reproductive cells are also called gametes. If the cell is still young (and developing) the term ovule is commonly used. In some plants, like algae this type of cell is called oosphere.

Contents 1 Production 1.1 In humans 1.2 In plants 2 Gallery 3 References 4 Other pages 5 Other websites

[change] Production

Ova are made and released by a female's ovaries. A birth, a mammal has all of her eggs, and from puberty, she releases an egg once a month until none are left. This is called oogenisis.

[change] In humans

When the ovum is fertilised by a male's sperm, it becomes a zygote, which develops into a new organism. The ovum is fertilized inside the female body, and the embryo then develops inside the uterus, being fed by the mothers placenta.

The ovum is the largest cell in the human body. You can see it without a microscope. The human ovum is between 100 and 200 µm long^[1][2][3][4].

[change] In plants

In fungi and many plants, ova are made inside archegonia through mitosis. The archegonium has a long 'neck' with the egg cell inside. When the egg is mature, the neck opens and sperm swims in to fertilize the egg.

In flowering plants, the female gametes are made of only eight cells, called the embryo sac, inside the ovule. The cell closest to the opening of the embryo sac becomes the egg cell. When pollinated, sperm swims into the embryo sac and fertilizes the egg. The zygote then develops into an embryo inside the ovule.

[change] Gallery

A human ovum

Sperm cells trying to fertilize an ovum

A sperm cell fusing with an ovum

[change] References

[change] Other pages

• Egg (biology)
• Fertilisation
• Pollination
• Sperm
• Zygote

[change] Other websites

• The Ovarian Kaleidoscope Database Describing the genes involved in making eggs

Human reproductive system Female anatomy Breasts – Cervix – Clitoris – Clitoral hood – Fallopian tubes – Bartholin's glands – Gräfenberg spot (G-spot) – Hymen – Labia – Ovaries – Skene's glands – Urethra – Uterus – Vagina – Vulva Female physiology Ejaculation – Estrogen – Orgasm – Ovum Male anatomy Bulbourethral glands – Corpus cavernosum – Ejaculatory ducts – Epididymis – Foreskin – Frenulum – Glans penis – Penis – Prostate – Rete testis – Scrotum – Seminal vesicles – Seminiferous tubules – Sertoli cell – Spermatic cord – Testicles (testes) – Urethra – Vasa deferentia Male physiology Ejaculation – Erection – Orgasm – Semen – Sperm – Testosterone Anatomy is the study of the parts of the body • Physiology is the study of how the body works