An intromittent organ is any external organ of a male organism that is specialized to deliver sperm during copulation. Intromittent organs are found most often in terrestrial species, as most non-mammalian aquatic species fertilize their eggs externally, although there are exceptions. For many species in the animal kingdom, the male intromittent organ is a hallmark characteristic of internal fertilization.
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👉 Intromittent organ in the context of Human penis
In human anatomy, the penis (/ˈpiːnɪs/; pl.: penises or penes; from the Latin pēnis, initially 'tail') is an external sex organ (intromittent organ) through which males ejaculate and urinate. Together with the testes and surrounding structures, the penis functions as part of the male reproductive system.
The main parts of the penis are the root, body, the epithelium, including the shaft skin, and the foreskin covering the glans. The body of the penis is made up of three columns of tissue: two corpora cavernosa on the dorsal side and corpus spongiosum between them on the ventral side. The urethra passes through the prostate gland, where it is joined by the ejaculatory ducts, and then through the penis. The urethra goes across the corpus spongiosum and ends at the tip of the glans as the opening, called the urinary meatus.
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Intromittent organ in the context of Penis
In many animals, a penis (/ˈpiːnɪs/; pl.: penises or penes) is the main male sexual organ used to inseminate females (or hermaphrodites) during copulation. Such organs occur in both vertebrates and invertebrates, but males do not bear a penis in every animal species. Furthermore, penises are not necessarily homologous.
The term penis applies to many intromittent organs, but not to all. As an example, the intromittent organ of most Cephalopoda is the hectocotylus, a specialized arm, and male spiders use their pedipalps. Even within the Vertebrata, there are morphological variants with specific terminology, such as hemipenes.
Intromittent organ in the context of 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. Male animals inseminate females in order to internally fertilize their egg cells.
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. Most birds use the "cloacal kiss," pressing cloacas together to transfer 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. After fertilization, embryos develop in eggs in oviparous species or inside the mother’s reproductive tract in viviparous ones.
Intromittent organ in the context of Hemipenis
A hemipenis (pl.: hemipenes) is one of a pair of intromittent organs of male squamates (snakes and lizards). Hemipenes are usually held inverted within the body, and are everted for reproduction via erectile tissue, much like that in the human penis. They come in a variety of shapes, depending on species, with ornamentation such as spikes.