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Parotoid Gland
The parotoid gland (alternatively, paratoid gland) is an external skin gland on the back, neck, and shoulder of some frogs (especially toads), and salamanders. It can secrete a number of milky alkaloid substances (depending on the species) known collectively as bufotoxins, which act as neurotoxins to deter predation. These cutaneous glands are called parotoid as they are somewhat similarly positioned to mammalian parotid glands, parotid gland, although the latter have a different function, excreting saliva within the mouth rather than externally excreted defensive chemicals. A study of the parotoid glands of the Colorado River toad in 1976 found that the parotoid glands were "composed of numerous Lobe (anatomy), lobules", each of which is a separate unit with a Lumen (anatomy), lumen surrounded by a double cell layer. The cell layers have interlocking microvilli. The study found that the outer cell layer resembled smooth muscle cells, with some organelles hypothesised to "function ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bufo Marinus From Australia
''Bufo'' is a genus of true toads in the amphibian family Bufonidae. As traditionally defined, it was a wastebasket genus containing a large number of toads from much of the world but following Taxonomy (biology), taxonomic reviews most of these have been moved to other genera, leaving only seventeen extant species from Europe, northern Africa and Asia in this genus, including the well-known common toad (''B. bufo''). Some of the genera that contain species formerly placed in ''Bufo'' are ''Anaxyrus'' (many North American species), ''Bufotes'' (European green toad and relatives), ''Duttaphrynus'' (many Asian species, including the Asian common toad introduced elsewhere), ''Epidalea'' (natterjack toad) and ''Rhinella'' (many Latin American species, including the cane toad introduced elsewhere). Description True toads have in common stocky figures and short legs, which make them relatively poor jumpers. Their dry skin is thick and "warty". Behind their eyes, ''Bufo'' species ha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lumen (anatomy)
In biology, a lumen (: lumina) is the inside space of a tubular structure, such as an artery or intestine. It comes . It can refer to: *the interior of a vessel, such as the central space in an artery, vein or capillary through which blood flows *the interior of the gastrointestinal tract *the pathways of the bronchi in the lungs *the interior of renal tubules and urinary collecting ducts *the pathways of the female genital tract, starting with a single pathway of the vagina, splitting up in two lumina in the uterus, both of which continue through the fallopian tubes *the fluid-filled cavity forming in the blastocyst during pre-implantation development called the blastocoel In cell biology, lumen is a membrane-defined space that is found inside several organelles, cellular components, or structures, including thylakoid, endoplasmic reticulum, Golgi apparatus, lysosome, mitochondrion, and microtubule. Transluminal procedures ''Transluminal procedures'' are procedures occur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bufotoxin
Bufotoxins are a family of toxic steroid lactones or substituted Substituted tryptamine, tryptamines of which some are toxic. They occur in the parotoid glands, skin, and poison of many toads (True toad, Bufonidae family) and other amphibians, and in some plants and mushrooms. The exact composition varies greatly with the specific source of the toxin. Composition Bufotoxins can contain 5-MeO-DMT, bufagins, bufalin, bufotalin, bufotenin, bufothionine, dehydrobufotenine, epinephrine, norepinephrine, and serotonin. Some authors have also used the term ''bufotoxin'' to describe the conjugate of a bufagin with suberylarginine. The toxic substances found in toads can be divided by chemical structure in two groups: #bufadienolides, which are cardiac glycosides (e.g., bufotalin, bufogenin), are compounds that may be fatal if consumed. #tryptamine-related substances (e.g., bufotenin), are sought after for entheogenic and/or recreational drug, recreational purposes by some individuals. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wart
Warts are non-cancerous viral growths usually occurring on the hands and feet but which can also affect other locations, such as the genitals or face. One or many warts may appear. They are distinguished from cancerous tumors as they are caused by a viral infection, such as a human papillomavirus, rather than a cancer growth. Factors that increase the risk include the use of public showers and pools, working with meat, eczema, and a weak immune system. The virus is believed to infect the host through the entrance of a skin wound. A number of types exist, including plantar warts, " filiform warts", and genital warts. Genital warts are often sexually transmitted. Without treatment, most types of warts resolve in months to years. A number of treatments may speed resolution, including salicylic acid applied to the skin and cryotherapy. In those who are otherwise healthy, they do not typically result in significant problems. Treatment of genital warts differs from that of o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Precursor (chemistry)
In chemistry, a precursor is a compound that participates in a chemical reaction that produces another compound. In biochemistry Biochemistry, or biological chemistry, is the study of chemical processes within and relating to living organisms. A sub-discipline of both chemistry and biology, biochemistry may be divided into three fields: structural biology, enzymology, a ..., the term "precursor" often refers more specifically to a chemical compound preceding another in a metabolic pathway, such as a protein precursor. Illicit drug precursors In 1988, the United Nations Convention Against Illicit Traffic in Narcotic Drugs and Psychotropic Substances introduced detailed provisions and requirements relating the control of precursors used to produce drugs of abuse. In Europe the Regulation (EC) No. 273/2004 of the European Parliament and of the Council on drug precursors was adopted on 11 February 2004. ( European law on drug precursors) Illicit explosives precursors On Ja ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cholesterol
Cholesterol is the principal sterol of all higher animals, distributed in body Tissue (biology), tissues, especially the brain and spinal cord, and in Animal fat, animal fats and oils. Cholesterol is biosynthesis, biosynthesized by all animal Cell (biology)#Eukaryotic cells, cells and is an essential structural and cholesterol signaling, signaling component of animal cell membranes. In vertebrates, hepatocyte, hepatic cells typically produce the greatest amounts. In the brain, astrocytes produce cholesterol and transport it to neurons. It is absent among prokaryotes (bacteria and archaea), although there are some exceptions, such as ''Mycoplasma'', which require cholesterol for growth. Cholesterol also serves as a Precursor (chemistry), precursor for the biosynthesis of steroid hormones, bile acid and vitamin D. Elevated levels of cholesterol in the blood, especially when bound to low-density lipoprotein (LDL, often referred to as "bad cholesterol"), may increase the risk of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cane Toad
The cane toad (''Rhinella marina''), also known as the giant neotropical toad or marine toad, is a large, Terrestrial animal, terrestrial true toad native to South America, South and mainland Central America, but which has been Introduced species, introduced to various islands throughout Oceania and the Caribbean, as well as Northern Australia. It is a member of the genus ''Rhinella'', which includes many true toad species found throughout Central and South America, but it was formerly assigned to the genus ''Bufo''. A fossil toad (specimen UCMP 41159) from the La Venta (Colombia), La Venta fauna of the late Miocene in Colombia is morphologically indistinguishable from modern cane toads from northern South America. It was discovered in a floodplain deposit, which suggests the ''R. marina'' habitat preferences have long been for open areas. The cane toad is a prolific breeder; females lay single-clump spawn (biology), spawns with thousands of egg (biology), eggs. Its reproducti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Smooth Muscle
Smooth muscle is one of the three major types of vertebrate muscle tissue, the others being skeletal and cardiac muscle. It can also be found in invertebrates and is controlled by the autonomic nervous system. It is non- striated, so-called because it has no sarcomeres and therefore no striations (''bands'' or ''stripes''). It can be divided into two subgroups, ''single-unit'' and ''multi-unit'' smooth muscle. Within single-unit muscle, the whole bundle or sheet of smooth muscle cells contracts as a syncytium. Smooth muscle is found in the walls of hollow organs, including the stomach, intestines, bladder and uterus. In the walls of blood vessels, and lymph vessels, (excluding blood and lymph capillaries) it is known as vascular smooth muscle. There is smooth muscle in the tracts of the respiratory, urinary, and reproductive systems. In the eyes, the ciliary muscles, iris dilator muscle, and iris sphincter muscle are types of smooth muscles. The iris dilator and s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microvilli
Microvilli (: microvillus) are microscopic cellular membrane protrusions that increase the surface area for diffusion and minimize any increase in volume, and are involved in a wide variety of functions, including absorption, secretion, cellular adhesion, and mechanotransduction. Structure Microvilli are covered in plasma membrane, which encloses cytoplasm and microfilaments. Though these are cellular extensions, there are little or no cellular organelles present in the microvilli. Each microvillus has a dense bundle of cross-linked actin filaments, which serves as its structural core. 20 to 30 tightly bundled actin filaments are cross-linked by bundling proteins fimbrin (or plastin-1), villin and espin to form the core of the microvilli. In the enterocyte microvillus, the structural core is attached to the plasma membrane along its length by lateral arms made of myosin 1a and Ca2+ binding protein calmodulin. Myosin 1a functions through a binding site for filamentous acti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lobe (anatomy)
In anatomy, a lobe is a clear anatomical division or extension of an organ (as seen for example in the brain, lung, liver, or kidney) that can be determined without the use of a microscope at the gross anatomy level. This is in contrast to the much smaller lobule, which is a clear division only visible under the microscope. Interlobar ducts connect lobes and interlobular ducts connect lobules. Examples of lobes *The four main lobes of the brain **the frontal lobe **the parietal lobe **the occipital lobe **the temporal lobe *The three lobes of the human cerebellum **the flocculonodular lobe **the anterior lobe **the posterior lobe *The two lobes of the thymus *The two and three lobes of the lungs ** Left lung: superior and inferior ** Right lung: superior, middle, and inferior *The four lobes of the liver ** Left lobe of liver ** Right lobe of liver ** Quadrate lobe of liver ** Caudate lobe of liver *The renal lobes of the kidney * Earlobes Examples of lobules *the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gland
A gland is a Cell (biology), cell or an Organ (biology), organ in an animal's body that produces and secretes different substances that the organism needs, either into the bloodstream or into a body cavity or outer surface. A gland may also function to remove unwanted substances such as urine from the body. There are two types of gland, each with a different method of secretion. Endocrine glands are ductless and secrete their products, hormones, directly into interstitial spaces to be taken up into the bloodstream. Exocrine glands secrete their products through a duct into a body cavity or outer surface. Glands are mostly composed of epithelium, epithelial tissue, and typically have a supporting framework of connective tissue, and a capsule. Structure Development Every gland is formed by an ingrowth from an epithelium, epithelial surface. This ingrowth may in the beginning possess a tubular structure, but in other instances glands may start as a solid column of cells which ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Colorado River Toad
The Colorado River toad (''Incilius alvarius''), also known as the Sonoran Desert toad, is a toad species found in northwestern Mexico and the southwestern United States. It is well known for its ability to exude toxins from glands within its skin that have psychoactive properties. Description The Colorado River toad can grow to about long and is the largest toad in the United States apart from the non-native cane toad (''Rhinella marina''). It has a smooth, leathery skin and is olive green or mottled brown in color. Just behind the large golden eye with horizontal pupil is a bulging kidney-shaped parotoid gland. Below this is a large circular pale green area which is the tympanum or ear drum. By the corner of the mouth there is a white wart and there are white glands on the legs. All these glands produce toxic secretions. Its call is described as, "a weak, low-pitched toot, lasting less than a second." Dogs (''Canis familiaris'') that have attacked toads have suffered paraly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
