Human fertilization is the union of a human egg and sperm, usually occurring in the ampulla of the fallopian tube. Image File history File links Acrosome_reaction_diagram. ... Image File history File links Acrosome_reaction_diagram. ... Categories: Biology stubs ... A human ovum An ovum (from Latin, loosely, egg or egg cell) is a female sex cell or gamete. ... The signifier sperm can refer to: (mass noun, from Greek sperma = seed) a substance which consists of spermatozoa and which is a component of semen (mass noun) semen itself (informally, count noun with plural sperm or sperms) a single spermatozoon (= sperm cell) sperma ceti (Latin ceti, genitive of cetus = whale... The ampulla of Vater is a sphincter (a small muscle) where the common bile duct enters the duodenum. ... Female internal reproductive anatomy The Fallopian tubes or oviducts are two very fine tubes leading from the ovaries of female mammals into the uterus. ...
There is a specific sequence of events that occur in fertilization:
The sperm passes through the corona radiata, the outermost cell layer of the egg.
This occurs with the aid of several enzymes possessed by the sperm that break down the proteins of the zona pellucida, the most important one being acrosin.
When the sperm penetrates the zona pellucida, the Acrosome reaction occurs. This makes the egg impermeable to any other sperms and prevents fertilization by more than one sperm.
The sperm's tail and mitochondria degenerate with the formation of the male pronucleus. This is why all mitochondria in humans are of maternal origin.
The male and female pronuclei fuse to form a new nucleus that is a combination of the genetic material from both the sperm and egg.
For the structure in neuroanatomy, see Corona radiata. ... Cells in culture, stained for keratin (red) and DNA (green). ... The zona pellucida is a glycoprotein membrane surrounding the plasma membrane of an oocyte. ... Ribbon diagram of the enzyme TIM. TIM is catalytically perfect, meaning its conversion rate is limited, or nearly limited to its substrate diffusion rate. ... A representation of the 3D structure of myoglobin, showing coloured alpha helices. ... Acrosin (EC 3. ... In sperm cells of many higher animals, the acrosome develops over the anterior half of its head. ... Drawing of a cell membrane A component of every biological cell, the selectively permeable cell membrane (or plasma membrane or plasmalemma) is a thin and structured bilayer of phospholipid and protein molecules that envelopes the cell. ... An oocyte or ovocyte is a female gametocyte or germ cell involved in reproduction. ... For the article on the figure of speech, see meiosis (figure of speech). ... A human ovum An ovum (from Latin, loosely, egg or egg cell) is a female sex cell or gamete. ... In cell biology, a mitochondrion is an organelle found in the cells of most eukaryotes. ... A pronucleus is the nucleus of a sperm or an egg cell prior to fertilization. ...
Diseases
Various disorders can arise from defects in the fertilization process.
Dispermy results from multiple sperm fertilizing an egg.
In vitro fertilization (IVF) is a technique in which egg cells are fertilized outside the mothers body in cases where conception is difficult or impossible through normal intercourse. ... Gamete intrafallopian transfer (GIFT) is an infertility treatment in which eggs are removed from a womans ovaries, and placed in one of the fallopian tubes, along with the mans sperm. ...
References
Dudek, Ronald W. High-Yield Embryology, 2nd ed. (2001). ISBN 0-7817-2132-6
Moore, Keith L. and T.V.N. Persaud. The Developing Human: Clinically Oriented Embryology, 7th ed. (2003). ISBN 0-7216-9412-8
Fertilisation (also known as conception, fecundation and syngamy) is fusion of gametes to form a new organism.
If fertilisation takes place, the sperm usually meet the ovum in the fallopian tube, requiring the sperm cells to swim from the upper vagina through the cervix and across the length of the uterus before reaching the fallopian tube—a considerable distance compared to the size of the sperm cell.
When gametes first fuse at fertilisation, the chromosomes donated by the parents are combined, and, in humans, this means that (2²³)², or 70,368,744,000,000, chromosomally different zygotes are possible, even assuming no chromosomal crossover.
The process of fertilization in the ovum of a mouse.
Fertilization consists in the union of the spermatozoön with the mature ovum (Fig.
Sometimes the fertilized ovum is arrested in the uterine tube, and there undergoes development, giving rise to a tubal pregnancy; or it may fall into the abdominal cavity and produce an abdominal pregnancy.
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