1.
Opioid
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Opioids are substances that act on opioid receptors to produce morphine-like effects. Opioids are most often used medically to relieve pain, and by people addicted to opioids, opioids include opiates, an older term that refers to such drugs derived from opium, including morphine itself. Other opioids are semi-synthetic and synthetic drugs such as hydrocodone, oxycodone and fentanyl, antagonist drugs such as naloxone, the terms opiate and narcotic are sometimes encountered as synonyms for opioid. Opiate is properly limited to the alkaloids found in the resin of the opium poppy although some include semi-synthetic derivatives. In some jurisdictions all controlled drugs are classified as narcotics. The term can have pejorative connotations and its use is discouraged where that is the case. Primarily used for relief, including anesthesia they are also used to suppress cough, suppress diarrhea, treat addiction, reverse opioid overdose. Extremely strong opioids are approved only for use such as immobilizing large mammals. Opioids act by binding to receptors, which are found principally in the central and peripheral nervous system. These receptors mediate both the psychoactive and the effects of opioids. The side effects of opioids may include itchiness, sedation, nausea, respiratory depression, constipation, Tolerance and dependence will develop with continuous use, requiring increasing doses and leading to a withdrawal syndrome upon abrupt discontinuation. The euphoria attracts recreational use, and frequent, escalating recreational use of opioids typically results in addiction, accidental overdose or concurrent use with other depressant drugs commonly results in death from respiratory depression. Because of opioid drugs reputation for addiction and fatal overdose, most are controlled substances, illicit production, smuggling, and addiction to opioids prompted treaties, laws and policing which have realized limited success. In 2013 between 28 and 38 million people used opioids illicitly, in 2011 an estimated 4 million people in the United States used opioids recreationally or were dependent on them. Current increased rates of use and addiction are attributed to over-prescription of opioid medications. Conversely, fears about over-prescribing, exaggerated side effects and addiction from opioids are similarly blamed for under-treatment of pain, the term opioid originated in the 1950s. It combines opium + -oid meaning opiate-like, by the late 1960s, research found that opiate effects are mediated by activation of specific molecular receptors in the nervous system, which were termed opioid receptors. The definition of opioid was later refined to refer to substances that have activities that are mediated by the activation of opioid receptors
2.
Scientific method
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The scientific method is a body of techniques for investigating phenomena, acquiring new knowledge, or correcting and integrating previous knowledge. To be termed scientific, a method of inquiry is commonly based on empirical or measurable evidence subject to specific principles of reasoning, experiments need to be designed to test hypotheses. The most important part of the method is the experiment. The scientific method is a process, which usually begins with observations about the natural world. Human beings are naturally inquisitive, so often come up with questions about things they see or hear. The best hypotheses lead to predictions that can be tested in various ways, in general, the strongest tests of hypotheses come from carefully controlled and replicated experiments that gather empirical data. Depending on how well the tests match the predictions, the hypothesis may require refinement. If a particular hypothesis becomes very well supported a theory may be developed. Although procedures vary from one field of inquiry to another, identifiable features are shared in common between them. The overall process of the method involves making conjectures, deriving predictions from them as logical consequences. A hypothesis is a conjecture, based on knowledge obtained while formulating the question, the hypothesis might be very specific or it might be broad. Scientists then test hypotheses by conducting experiments, the purpose of an experiment is to determine whether observations agree with or conflict with the predictions derived from a hypothesis. Experiments can take anywhere from a college lab to CERNs Large Hadron Collider. There are difficulties in a statement of method, however. Though the scientific method is presented as a fixed sequence of steps. Not all steps take place in scientific inquiry, and are not always in the same order. Some philosophers and scientists have argued there is no scientific method, such as Lee Smolin. Nola and Sankey remark that For some, the idea of a theory of scientific method is yester-years debate
3.
Hallucinogen
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A hallucinogen is a psychoactive agent which can cause hallucinations, perceptual anomalies, and other substantial subjective changes in thoughts, emotion, and consciousness. The common types of hallucinogens are psychedelics, dissociatives and deliriants, although hallucinations are a common symptom of amphetamine psychosis, amphetamines are not considered hallucinogens, as they are not a primary effect of the drugs themselves. While hallucinations can occur when abusing stimulants, the nature of stimulant psychosis is not unlike delirium, a debate persists on criteria which would easily differentiate a substance which is psychedelic from one hallucinogenic. Sir Thomas Browne in 1646 coined the term hallucination from the Latin word alucinari meaning to wander in the mind, the term psychedelic is derived from the Ancient Greek words psychē and dēloun, or mind-revealing. A hallucinogen and a psychedelic may refer correctly to the same substance, hallucinations and psychedelia may both refer to the same aspects of subjective experience in a given instance. A hallucinogen in this sense refers to any substance which causes changes in perception or hallucinations. In contrast to Hollisters original criteria, adverse effects may predominate with some hallucinogens with this application of the term, the word psychedelic was coined to express the idea of a drug that makes manifest a hidden but real aspect of the mind. One explanatory model for the experiences provoked by psychedelics is the reducing valve concept, in this view, the drugs disable the brains filtering ability to selectively prevent certain perceptions, emotions, memories and thoughts from ever reaching the conscious mind. This effect has been described as mind expanding, or consciousness expanding, many designer drugs and research chemicals are hallucinogenic in nature, such as those in the 2C and NBOMe families. Dissociatives produce analgesia, amnesia and catalepsy at anesthetic doses, dissociative symptoms include the disruption or compartmentalization of. the usually integrated functions of consciousness, memory, identity or perception. p. 523 Dissociation of sensory input can cause derealization, the perception of the world as being dream-like or unreal. The primary dissociatives achieve their effect through blocking the signals received by the NMDA receptor set and include ketamine, methoxetamine, phencyclidine, dextromethorphan, however, dissociation is also remarkably administered by salvinorin As potent κ-opioid receptor agonism. Some dissociatives can have CNS depressant effects, thereby carrying similar risks as opioids, DXM in higher doses can increase heart rate and blood pressure and still depress respiration. Inversely, PCP can have unpredictable effects and has often been classified as a stimulant. While many have reported that they feel no pain while under the effects of PCP, DXM and Ketamine, this does not fall under the usual classification of anesthetics in recreational doses. Rather, true to their name, they process pain as a kind of far away sensation, pain, although present, becomes a disembodied experience, as for probably the most common dissociative, nitrous oxide, the principal risk seems to be due to oxygen deprivation. Injury from falling is also a danger, as nitrous oxide may cause loss of consciousness. Because of the level of physical activity and relative imperviousness to pain induced by PCP
4.
Guinea pig
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The guinea pig, cavy or domestic guinea pig, or cuy for livestock breeds, is a species of rodent belonging to the family Caviidae and the genus Cavia. Despite their common name, these animals are not in the pig family Suidae, recent studies applying molecular markers, in addition to studying the skull and skeletal morphology of current and mummified animals, revealed that the ancestor is most likely Cavia tschudii. Since the 1960s, efforts have made to increase consumption of the animal outside South America. In Western societies, the guinea pig has enjoyed widespread popularity as a household pet since its introduction by European traders in the 16th century. Their docile nature, friendly, even affectionate responsiveness to handling and feeding, biological experimentation on guinea pigs has been carried out since the 17th century. They are still used in research, primarily as models for medical conditions such as juvenile diabetes, tuberculosis, scurvy. The guinea pig was first domesticated as early as 5000 BC for food by tribes in the Andean region of South America, statues dating from circa 500 BC to 500 AD that depict guinea pigs have been unearthed in archaeological digs in Peru and Ecuador. The Moche people of ancient Peru worshipped animals and often depicted the guinea pig in their art, from about 1200 AD to the Spanish conquest in 1532, selective breeding resulted in many varieties of domestic guinea pigs, which form the basis for some of the modern domestic breeds. They continue to be a source in the region, many households in the Andean highlands raise the animal. Folklore traditions involving guinea pigs are numerous, they are exchanged as gifts, used in social and religious ceremonies. They also play a role in healing rituals by folk doctors, or curanderos, who use the animals to diagnose diseases such as jaundice, rheumatism, arthritis. They are rubbed against the bodies of the sick, and are seen as a supernatural medium, black guinea pigs are considered especially useful for diagnoses. The animal also may be cut open and its entrails examined to determine whether the cure was effective and these methods are widely accepted in many parts of the Andes, where Western medicine is either unavailable or distrusted. Spanish, Dutch, and English traders brought guinea pigs to Europe, the guinea pig was first described in the West in 1554 by the Swiss naturalist Conrad Gessner. Its binomial scientific name was first used by Erxleben in 1777, it is an amalgam of Pallas generic designation, the scientific name of the common species is Cavia porcellus, with porcellus being Latin for little pig. Cavia is New Latin, it is derived from cabiai, the name in the language of the Galibi tribes once native to French Guiana. Cabiai may be an adaptation of the Portuguese çavia, which is derived from the Tupi word saujá. Guinea pigs are called quwi or jaca in Quechua and cuy or cuyo in the Spanish of Ecuador, Peru, and Bolivia
5.
Brain
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The brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. The brain is located in the head, usually close to the organs for senses such as vision. The brain is the most complex organ in a vertebrates body, in a human, the cerebral cortex contains approximately 15–33 billion neurons, each connected by synapses to several thousand other neurons. Physiologically, the function of the brain is to exert centralized control over the other organs of the body, the brain acts on the rest of the body both by generating patterns of muscle activity and by driving the secretion of chemicals called hormones. This centralized control allows rapid and coordinated responses to changes in the environment, the operations of individual brain cells are now understood in considerable detail but the way they cooperate in ensembles of millions is yet to be solved. This article compares the properties of brains across the range of animal species. It deals with the human brain insofar as it shares the properties of other brains, the ways in which the human brain differs from other brains are covered in the human brain article. Several topics that might be covered here are instead covered there because more can be said about them in a human context. The most important is brain disease and the effects of brain damage, the shape and size of the brain varies greatly between species, and identifying common features is often difficult. Nevertheless, there are a number of principles of architecture that apply across a wide range of species. Some aspects of structure are common to almost the entire range of animal species, others distinguish advanced brains from more primitive ones. The simplest way to gain information about brain anatomy is by visual inspection, Brain tissue in its natural state is too soft to work with, but it can be hardened by immersion in alcohol or other fixatives, and then sliced apart for examination of the interior. Visually, the interior of the consists of areas of so-called grey matter, with a dark color, separated by areas of white matter. Further information can be gained by staining slices of tissue with a variety of chemicals that bring out areas where specific types of molecules are present in high concentrations. It is also possible to examine the microstructure of brain tissue using a microscope, the brains of all species are composed primarily of two broad classes of cells, neurons and glial cells. Glial cells come in types, and perform a number of critical functions, including structural support, metabolic support, insulation. Neurons, however, are considered the most important cells in the brain. The property that makes neurons unique is their ability to send signals to target cells over long distances
6.
Mouse
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A mouse is a small rodent characteristically having a pointed snout, small rounded ears, a body-length scaly tail and a high breeding rate. The best known species is the common house mouse. It is also a popular pet, in some places, certain kinds of field mice are locally common. They are known to invade homes for food and shelter, domestic mice sold as pets often differ substantially in size from the common house mouse. This is attributable both to breeding and to different conditions in the wild, the most well known strain, the white lab mouse, has more uniform traits that are appropriate to its use in research. The American white-footed mouse and the mouse, as well as other common species of mouse-like rodents around the world. These, however, are in other genera, cats, wild dogs, foxes, birds of prey, snakes and even certain kinds of arthropods have been known to prey heavily upon mice. Nevertheless, because of its adaptability to almost any environment. Mice, in contexts, can be considered vermin which are a major source of crop damage, causing structural damage. In North America, breathing dust that has come in contact with mouse excrement has been linked to hantavirus, primarily nocturnal animals, mice compensate for their poor eyesight with a keen sense of hearing, and rely especially on their sense of smell to locate food and avoid predators. Mice build intricate burrows in the wild and these burrows typically have long entrances and are equipped with escape tunnels or routes. In at least one species, the design of a burrow is a genetic trait. Breeding onset is at about 50 days of age in females and males, although females may have their first estrus at 25–40 days. Mice are polyestrous and breed year round, ovulation is spontaneous, the duration of the estrous cycle is 4–5 days and estrus itself lasts about 12 hours, occurring in the evening. Vaginal smears are useful in timed matings to determine the stage of the estrous cycle, mating is usually nocturnal and may be confirmed by the presence of a copulatory plug in the vagina up to 24 hours post-copulation. The presence of sperm on a smear is also a reliable indicator of mating. Female mice housed together tend to go into anestrus and do not cycle, if exposed to a male mouse or the pheromones of a male mouse, most of the females will go into estrus in about 72 hours. This synchronization of the cycle is known as the Whitten effect
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