**Historical Discoveries**:
– Non-mammalian animal egg observation
– Doctrine of ex ovo omne vivum by William Harvey
– Karl Ernst von Baer’s discovery of mammalian ovum in 1827
– Oskar Hertwig’s observation of spermatozoa fusion with ova in 1876
– Rejection of spontaneous generation and preformationism
**Characteristics and Development**:
– Ova known as egg cells
– Ovule term for young ovum
– Ova produced by ovaries in female gonads
– Finite number of oocytes in females
– Existence of ovarian stem cells in mammalian ovary
– Ovum one of the largest cells in the human body
– Human ovum measures approximately 120μm in diameter
– Ova mature via oogenesis
– Process of oogenesis begins before birth
– Hormones regulate the oogenesis process
**Structural Components**:
– Ooplasm contains cytoplasm, spongioplasm, and deutoplasm
– Mammalian ova contain a small amount of nutritive yolk
– Nutritive yolk nourishes the embryo in early development
– Bird eggs contain enough yolk for chick throughout incubation
– Ooplasm contains germinal vesicle and germinal disc
– Nucleus holds genetic material in egg cells
– Mitochondria provide energy in egg cells
– Polar bodies are byproducts of meiosis
**Reproductive Function**:
– Essential for sexual reproduction
– Fusion with sperm to form zygote
– Genetic material passed from mother
– Initiates embryo development
– Key to genetic information transmission
**Biological Significance**:
– Study of fertilization and embryonic development
– Research on reproductive technologies
– Understanding genetic inheritance
– Study of cell division processes
– Advancements in reproductive medicine
The egg cell or ovum (pl.: ova) is the female reproductive cell, or gamete, in most anisogamous organisms (organisms that reproduce sexually with a larger, female gamete and a smaller, male one). The term is used when the female gamete is not capable of movement (non-motile). If the male gamete (sperm) is capable of movement, the type of sexual reproduction is also classified as oogamous. A nonmotile female gamete formed in the oogonium of some algae, fungi, oomycetes, or bryophytes is an oosphere. When fertilized, the oosphere becomes the oospore.[clarification needed]
| Egg cell | |
|---|---|
 A human egg cell with surrounding corona radiata | |
| Details | |
| Identifiers | |
| Latin | ovum |
| Greek | Ωάριο (oário) |
| MeSH | D010063 |
| FMA | 67343 |
| Anatomical terms of microanatomy | |
When egg and sperm fuse during fertilisation, a diploid cell (the zygote) is formed, which rapidly grows into a new organism.