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The skull and crossbones symbol traditionally used to label a poisonous substance.
In the context of biology, poisons are substances that cause injury, illness, or death to organisms, usually by chemical reaction or other activity on the molecular scale. Some poisons are also toxins, and a distinction between the two terms is not always observed, even among scientists. The derivative forms "toxic" and "poisonous" are synonymous. Within chemistry and physics, a poison is a substance that obstructs or inhibits a reaction, for example by binding to a catalyst. Poisons have been known to be symbolized by the skull and crossbones (shown beside).
Contact or absorption of poisons can cause rapid death or impairment. Agents that act on the nervous system can paralyze in seconds or less, and include both biologically derived neurotoxins and so-called nerve gases, which may be synthesized for warfare or industry. Inhaled or ingested cyanide almost instantly starves the body of energy by poisoning mitochondria and the synthesis of ATPFor other uses of the initials ATP, see ATP (disambiguation Adenosine triphosphate ATP is the nucleotide known in biochemistry as the " molecular currency" of intracellular energy transfer; that is, ATP is able to store and transport chemical energy withi. Intravenous injection of an unnaturally high concentration of potassium chlorideThe chemical compound potassium chloride (KCl) is a metal halide which is used in medicine, scientific applications, food processing and in judicial execution through lethal injection. It occurs naturally as the mineral sylvite and in combination with sod, such as in the execution of prisoners in parts of the United States, quickly stops the heartThis page is about the muscular organ, the Heart . For other meanings of the word, see Heart (disambiguation). The heart ( Latin cor is a hollow, muscular organ that pumps blood through the blood vessels by repeated, rhythmic contractions. The term cardia by eliminating the cell potentialIn biological cells that are electrically "at rest," the cytosol possesses a uniform electric potential or voltage compared to the extracellular solution. This voltage is the resting cell potential also sometimes called the transmembrane potential of the necessary for muscle contractionskeletal muscle A muscle contraction (also known as a muscle twitch or simply twitch occurs when a muscle cell (called a muscle fiber) shortens. Locomotion is possible only through the repeated contraction of many muscles at the correct times. For most mu. Such rapid reactions are often called acute poisoning.
A poison may also act slowly. This is known as chronic poisoning and is most common for poisons that bioaccumulate. Examples of these types of poisons are mercuryMercury also called quicksilver is a chemical element in the periodic table that has the symbol Hg ( L. hydrargyrum and atomic number 80. A heavy, silvery, transition metal, mercury is one of only two elements that are liquid at room temperature (the othe, and lead.
Many substances regarded as poisons are toxic only indirectly. An example is "wood alcohol" or methanol, which is not poisonous itself, but is chemically converted to toxic formaldehyde in the liver. Many drug molecules are made toxic in the liver, and the genetic variability of certain liver enzymes makes the toxicity of many compounds differ between one individual and the next.
Milkweeds (Asclepias sp.) produce glycosides which are toxic to most organisms. (It is unlikely that any organism will eat much because of the extremely bitter taste.) Monarch butterfly larvae, however, are not susceptible to the toxin; in fact they accumulate it in their bodies as they eat the leaves of their host plant. Any predator who wishes to make a meal of an adult monarch will tend to be dissuaded by the bitter taste, and learn to leave the brightly colored insects alone. This gives considerable protection for monarchs from birds and other predators.The study of the symptoms, mechanisms, treatment and diagnosis of biological poisoning is known as toxicology.
Exposure to radioactive substances can produce radiation poisoning, an unrelated phenomenon.
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