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Semen Podyachev
Semen, also known as seminal fluid, is a bodily fluid that contains spermatozoa which is secreted by the male gonads (sexual glands) and other sexual organs of male or hermaphroditic animals. In humans and placental mammals, seminal fluid is ejaculated through the penis and contains proteolytic and other enzymes as well as fructose, which promote the survival of spermatozoa and provide a medium through which they can move or "swim" from the vagina into the uterus to fertilize the female ovum and form a zygote. Semen is collected from animals for artificial insemination or cryoconservation of genetic material. Cryoconservation of animal genetic resources is a practice that calls for the collection of semen in efforts for conservation of a particular breed. Physiology Fertilization Depending on the species, spermatozoa can fertilize ova externally or internally. In external fertilization, the spermatozoa fertilize the ova directly, outside of the female's sexual organs. Fem ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spermatozoa
A spermatozoon (; also spelled spermatozoön; : spermatozoa; ) is a motile sperm cell (biology), cell produced by male animals relying on internal fertilization. A spermatozoon is a moving form of the ploidy, haploid cell (biology), cell that is the male gamete that Fertilization, joins with an ovum to form a zygote. (A zygote is a single cell, with a complete set of chromosomes, that normally develops into an embryo.) Sperm cells contribute approximately half of the nuclear gene, genetic information to the diploid offspring (excluding, in most cases, mitochondrial DNA). In mammals, the sex of the offspring is determined by the sperm cell: a spermatozoon bearing an X chromosome will lead to a female (XX) offspring, while one bearing a Y chromosome will lead to a male (XY) offspring. Sperm cells were first observed in Antonie van Leeuwenhoek's laboratory in 1677. Mammalian spermatozoa Humans The sperm cell of ''Homo sapiens'' is the small Gamete, reproductive cell produced by m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fertilization
Fertilisation or fertilization (see American and British English spelling differences#-ise, -ize (-isation, -ization), spelling differences), also known as generative fertilisation, syngamy and impregnation, is the fusion of gametes to give rise to a zygote and initiate its development into a new individual organism or offspring. While processes such as insemination or pollination, which happen before the fusion of gametes, are also sometimes informally referred to as fertilisation, these are technically separate processes. The cycle of fertilisation and development of new individuals is called sexual reproduction. During double fertilisation in angiosperms, the haploid male gamete combines with two haploid polar nuclei to form a triploid primary endosperm nucleus by the process of vegetative fertilisation. History In antiquity, Aristotle conceived the formation of new individuals through fusion of male and female fluids, with form and function emerging gradually, in a mode c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Insemination
Insemination is the introduction of sperm (in semen) into a female or hermaphrodite's reproductive system in order to fertilize the ovum through sexual reproduction. The sperm enters into the uterus of a mammal or the oviduct of an oviparous (egg-laying) animal. Female humans and other mammals are inseminated during sexual intercourse or copulation, but can also be inseminated by artificial insemination. In humans, the act and form of insemination has legal, moral and interpersonal implications. However, whether insemination takes place naturally or by artificial means, the pregnancy and the progress of it will be the same. Insemination may be called in vivo fertilisation (from ''in vivo'' meaning "within the living") because an egg is fertilized inside the body, this is in contrast with in vitro fertilisation (IVF). Plants In plants, the fertilization process is referred to as pollination. It is the process of transfer of pollen grains from one anther to the stigma of oth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Internal Fertilization
Internal fertilization is the union of an egg and sperm cell during sexual reproduction inside the female body. Internal fertilization, unlike its counterpart, external fertilization, brings more control to the female with reproduction. For internal fertilization to happen there needs to be a method for the male to introduce the sperm into the female's reproductive tract. Most taxa that reproduce by internal fertilization are gonochoric. Male mammals, reptiles, and certain other vertebrates transfer sperm into the female's vagina or cloaca through an intromittent organ during copulation. In most birds, the cloacal kiss is used, the two animals pressing their cloacas together while transferring sperm. Salamanders, spiders, some insects and some molluscs undertake internal fertilization by transferring a spermatophore, a bundle of sperm, from the male to the female. Following fertilization, the embryos are laid as eggs in oviparous organisms, or continue to develop inside the r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
