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Cloaca
A cloaca ( ), : cloacae ( or ), or vent, is the rear orifice that serves as the only opening for the digestive (rectum), reproductive, and urinary tracts (if present) of many vertebrate animals. All amphibians, reptiles, birds, cartilaginous fish and a few mammals ( monotremes, afrosoricids, and marsupial moles, etc.) have this orifice, from which they excrete both urine and feces; this is in contrast to most placental mammals, which have separate orifices for evacuation and reproduction. Excretory openings with analogous purpose in some invertebrates are also sometimes called cloacae. Mating through the cloaca is called cloacal copulation and cloacal kissing. The cloacal region is also often associated with a secretory organ, the cloacal gland, which has been implicated in the scent-marking behavior of some reptiles, marsupials, amphibians, and monotremes. Etymology The word is from the Latin verb ''cluo'', "(I) cleanse", thus the noun ''cloaca'', " sewer, drain" ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amphibian
Amphibians are ectothermic, anamniote, anamniotic, tetrapod, four-limbed vertebrate animals that constitute the class (biology), class Amphibia. In its broadest sense, it is a paraphyletic group encompassing all Tetrapod, tetrapods, but excluding the amniotes (tetrapods with an amniotic membrane, such as modern reptiles, birds and mammals). All extant taxon, extant (living) amphibians belong to the monophyletic subclass (biology), subclass Lissamphibia, with three living order (biology), orders: Anura (frogs and toads), Urodela (salamanders), and Gymnophiona (caecilians). Evolved to be mostly semiaquatic, amphibians have adapted to inhabit a wide variety of habitats, with most species living in freshwater ecosystem, freshwater, wetland or terrestrial ecosystems (such as riparian woodland, fossorial and even arboreal habitats). Their biological life cycle, life cycle typically starts out as aquatic animal, aquatic larvae with gills known as tadpoles, but some species have devel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bird Penis
A penis (; : penises or penes) is a sex organ through which male and hermaphrodite animals expel semen during copulation, and through which male placental mammals and marsupials also urinate. The term ''penis'' applies to many intromittent organs of vertebrates and invertebrates, 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. Etymology The word "penis" is taken from the Latin word for "tail". Some derive that from Indo-European ''*pesnis'', and the Greek word πέος = "penis" from Indo-European ''*pesos''. Prior to the adoption of the Latin word in English, the penis was referred to as a "yard". The Oxford English Dictionary cites an example of the word ''yard'' used in this sense from 1379, and notes that in his ''Physical Dictionary'' of 1684, Steven Blanka ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reproductive System
The reproductive system of an organism, also known as the genital system, is the biological system made up of all the anatomical organs involved in sexual reproduction. Many non-living substances such as fluids, hormones, and pheromones are also important accessories to the reproductive system. Unlike most organ systems, the sexes of differentiated species often have significant differences. These differences allow for a combination of genetic material between two individuals, which allows for the possibility of greater genetic fitness of the offspring.Reproductive System 2001 Body Guide powered by Adam Animals In mammals, the major organs of the reproductive system include the external gen ...[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reptile
Reptiles, as commonly defined, are a group of tetrapods with an ectothermic metabolism and Amniotic egg, amniotic development. Living traditional reptiles comprise four Order (biology), orders: Testudines, Crocodilia, Squamata, and Rhynchocephalia. About 12,000 living species of reptiles are listed in the Reptile Database. The study of the traditional reptile orders, customarily in combination with the study of modern amphibians, is called herpetology. Reptiles have been subject to several conflicting Taxonomy, taxonomic definitions. In Linnaean taxonomy, reptiles are gathered together under the Class (biology), class Reptilia ( ), which corresponds to common usage. Modern Cladistics, cladistic taxonomy regards that group as Paraphyly, paraphyletic, since Genetics, genetic and Paleontology, paleontological evidence has determined that birds (class Aves), as members of Dinosauria, are more closely related to living crocodilians than to other reptiles, and are thus nested among re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monotreme
Monotremes () are mammals of the order Monotremata. They are the only group of living mammals that lay eggs, rather than bearing live young. The extant monotreme species are the platypus and the four species of echidnas. Monotremes are typified by structural differences in their brains, jaws, digestive tract, reproductive tract, and other body parts, compared to the more common mammalian types. Although they are different from other living mammals in that they lay eggs, female monotremes are like other mammals in that they nurse their young with milk. Monotremes have been considered by some authors to be members of Australosphenida, a clade that contains extinct mammals from the Jurassic and Cretaceous of Madagascar, South America, and Australia, but this categorization is disputed and their taxonomy is under debate. All extant species of monotremes are indigenous to Australia and New Guinea, although they were also present during the Late Cretaceous and Paleocene epochs in s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Birds
Birds are a group of warm-blooded vertebrates constituting the class (biology), class Aves (), characterised by feathers, toothless beaked jaws, the Oviparity, laying of Eggshell, hard-shelled eggs, a high Metabolism, metabolic rate, a four-chambered heart, and a strong yet lightweight Bird skeleton, skeleton. Birds live worldwide and range in size from the bee hummingbird to the common ostrich. There are over 11,000 living species and they are split into 44 Order (biology), orders. More than half are passerine or "perching" birds. Birds have Bird wing, wings whose development varies according to species; the only known groups without wings are the extinct moa and elephant birds. Wings, which are modified forelimbs, gave birds the ability to fly, although further evolution has led to the Flightless bird, loss of flight in some birds, including ratites, penguins, and diverse endemism, endemic island species. The digestive and respiratory systems of birds are also uniquely a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Copulation (zoology)
In zoology, copulation is animal sexual behavior in which a male introduces sperm into the female's body, especially directly into her reproductive tract. This is an aspect of mating. Many aquatic animals use external fertilization, whereas internal fertilization may have developed from a need to maintain gametes in a liquid medium in the Late Ordovician epoch. Internal fertilization with many vertebrates (such as all reptiles, some fish, and most birds) occurs via cloacal copulation, known as cloacal kiss (see also hemipenis), while most mammals copulate vaginally, and many basal vertebrates reproduce sexually with external fertilization. In spiders and insects Spiders are often confused with insects, but they are not insects; instead, they are arachnids. Spiders have separate male and female sexes. Before mating and copulation, the male spider spins a small web and ejaculates on to it. He then stores the sperm in reservoirs on his large pedipalps, from which he tran ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Body Orifice
A body orifice is any opening in the body of an animal. External In a typical mammalian body such as the human body, the external body orifices are: * The nostrils, for breathing and the associated sense of smell * The mouth, for eating, drinking, breathing, and vocalizations such as speech * The ear canals, for the sense of hearing * The nasolacrimal ducts, to carry tears from the lacrimal sac into the nasal cavity * The anus, for defecation * The urinary meatus, for urination in males and females and ejaculation in males * In females, the vagina, for menstruation, copulation and birth * The nipple orifices Other animals may have some other body orifices: *cloaca, in birds, reptiles, amphibians, and a few mammals, such as monotremes. *siphon in mollusks, arthropods, and some other animals Internal Internal orifices include the orifices of the outflow tracts of the heart, between the heart valves. See also *Internal urethral orifice *Mucosa * Mucocutaneous boundary *Meatus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Feces
Feces (also known as faeces American and British English spelling differences#ae and oe, or fæces; : faex) are the solid or semi-solid remains of food that was not digested in the small intestine, and has been broken down by bacteria in the large intestine. Feces contain a relatively small amount of metabolic waste products such as bacterially-altered bilirubin and dead epithelial cells from the lining of the gut. Feces are discharged through the anus or cloaca during defecation. Feces can be used as fertilizer or soil conditioner in agriculture. They can also be burned as dry animal dung fuel, fuel or dried and used for wattle and daub, construction. Some medicinal uses have been found. In the case of human feces, fecal transplants or fecal bacteriotherapy are in use. Urine and feces together are called excretion, excreta. Characteristics The distinctive odor of feces is due to skatole, and thiols (sulfur-containing compounds), as well as amines and carboxylic acids. Sk ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Placental Mammal
Placental mammals ( infraclass Placentalia ) are one of the three extant subdivisions of the class Mammalia, the other two being Monotremata and Marsupialia. Placentalia contains the vast majority of extant mammals, which are partly distinguished from monotremes and marsupials in that the fetus is carried in the uterus of its mother to a relatively late stage of development. The name is something of a misnomer, considering that marsupials also nourish their fetuses via a placenta, though for a relatively briefer period, giving birth to less-developed young, which are then nurtured for a period inside the mother's pouch. Placentalia represents the only living group within Eutheria, which contains all mammals that are more closely related to placentals than they are to marsupials. Anatomical features Placental mammals are anatomically distinguished from other mammals by: * a sufficiently wide opening at the bottom of the pelvis to allow the birth of a large baby relative to the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Urination
Urination is the release of urine from the bladder through the urethra in Placentalia, placental mammals, or through the cloaca in other vertebrates. It is the urinary system's form of excretion. It is also known medically as micturition, voiding, uresis, or, rarely, emiction, and known colloquially by various names including peeing, weeing, pissing, and euphemistically number one. The process of urination is under voluntary control in healthy humans and #Animals, other animals, but may occur as a reflex in infants, some elderly individuals, and those with neurological injury. It is normal for adult humans to urinate up to seven times during the day. In some animals, in addition to expelling waste material, urination #Other animals, can mark territory or express submissiveness. Physiologically, urination involves coordination between the central nervous system, central, autonomic nervous system, autonomic, and somatic nervous systems. Brain centres that regulate urination in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gut (anatomy)
The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the digestive system that leads from the mouth to the anus. The tract is the largest of the body's systems, after the cardiovascular system. The GI tract contains all the major organs of the digestive system, in humans and other animals, including the esophagus, stomach, and intestines. Food taken in through the mouth is digested to extract nutrients and absorb energy, and the waste expelled at the anus as feces. ''Gastrointestinal'' is an adjective meaning of or pertaining to the stomach and intestines. Most animals have a "through-gut" or complete digestive tract. Exceptions are more primitive ones: sponges have small pores ( ostia) throughout their body for digestion and a larger dorsal pore ( osculum) for excretion, comb jellies have both a ventral mouth and dorsal anal pores, while cnidarians and acoels have a single pore for both digestion and excretion. The huma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
