Controlled Substances Act
The Controlled Substances Act is the statute establishing federal U. S. drug policy under which the manufacture, possession and distribution of certain substances is regulated. It was passed by the 91st United States Congress as Title II of the Comprehensive Drug Abuse Prevention and Control Act of 1970 and signed into law by President Richard Nixon; the Act served as the national implementing legislation for the Single Convention on Narcotic Drugs. The legislation created five schedules, with varying qualifications for a substance to be included in each. Two federal agencies, the Drug Enforcement Administration and the Food and Drug Administration, determine which substances are added to or removed from the various schedules, although the statute passed by Congress created the initial listing. Congress has sometimes scheduled other substances through legislation such as the Hillory J. Farias and Samantha Reid Date-Rape Prevention Act of 2000, which placed gamma hydroxybutyrate in Schedule I and sodium oxybate in Schedule III.
Classification decisions are required to be made on criteria including potential for abuse accepted medical use in treatment in the United States, international treaties. The nation first outlawed addictive drugs in the early 1900s and the International Opium Convention helped lead international agreements regulating trade; the Food and Drugs Act of 1906 was the beginning of over 200 laws concerning public health and consumer protections. Others were the Federal Food and Cosmetic Act, the Kefauver Harris Amendment of 1962. In 1969, President Richard Nixon announced that the Attorney General, John N. Mitchell, was preparing a comprehensive new measure to more meet the narcotic and dangerous drug problems at the federal level by combining all existing federal laws into a single new statute. With the help of White House Counsel head, John Dean; the CSA not only combined existing federal drug laws and expanded their scope, but it changed the nature of federal drug law policies and expanded Federal law enforcement pertaining to controlled substances.
Title II, Part F of the Comprehensive Drug Abuse Prevention and Control Act of 1970 established the National Commission on Marijuana and Drug Abuse—known as the Shafer Commission after its chairman, Raymond P. Shafer—to study cannabis abuse in the United States. During his presentation of the commission's First Report to Congress and Shafer recommended the decriminalization of marijuana in small amounts, with Shafer stating, he criminal law is too harsh a tool to apply to personal possession in the effort to discourage use, it implies. The actual and potential harm of use of the drug is not great enough to justify intrusion by the criminal law into private behavior, a step which our society takes only with the greatest reluctance. Rufus King notes that this stratagem was similar to that used by Harry Anslinger when he consolidated the previous anti-drug treaties into the Single Convention and took the opportunity to add new provisions that otherwise might have been unpalatable to the international community.
According to David T. Courtwright, "the Act was part of an omnibus reform package designed to rationalize, in some respects to liberalize, American drug policy." It provided support for drug treatment and research. King notes that the rehabilitation clauses were added as a compromise to Senator Jim Hughes, who favored a moderate approach; the bill, as introduced by Senator Everett Dirksen, ran to 91 pages. While it was being drafted, the Uniform Controlled Substances Act, to be passed by state legislatures, was being drafted by the Department of Justice. Since its enactment in 1970, the Act has been amended numerous times: The 1976 Medical Device Regulation Act; the Psychotropic Substances Act of 1978 added provisions implementing the Convention on Psychotropic Substances. The Controlled Substances Penalties Amendments Act of 1984; the 1986 Federal Analog Act for chemicals "substantially similar" in Schedule I and II to be listed The 1988 Chemical Diversion and Trafficking Act added provisions implementing the United Nations Convention Against Illicit Traffic in Narcotic Drugs and Psychotropic Substances that went into force on November 11, 1990.
1990 The Anabolic Steroids Act, passed as part of the Crime Control Act of 1990, which placed anabolic steroids into Schedule III The 1993 Domestic Chemical Diversion and Control Act in response to methamphetamine trafficking. The 2008 Ryan Haight Online Pharmacy Consumer Protection Act The 2010 Electronic Prescriptions for Controlled Substances; the 2010 Secure and Responsible Drug Disposal Act, to allow pharmacies to operate take-back programs for controlled subtance medications in response to the US opioid epidemic. The Controlled Substances Act consists of 2 subchapters. Subchapter I defines Schedules I-V, lists chemicals used in the manufacture of controlled substances, differentiates lawful and unlawful manufacturing and possession of controlled substances, including possession of Schedule I drugs for personal use.
Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group on the periodic table, a reactive nonmetal, an oxidizing agent that forms oxides with most elements as well as with other compounds. By mass, oxygen is the third-most abundant element in the universe, after helium. At standard temperature and pressure, two atoms of the element bind to form dioxygen, a colorless and odorless diatomic gas with the formula O2. Diatomic oxygen gas constitutes 20.8% of the Earth's atmosphere. As compounds including oxides, the element makes up half of the Earth's crust. Dioxygen is used in cellular respiration and many major classes of organic molecules in living organisms contain oxygen, such as proteins, nucleic acids and fats, as do the major constituent inorganic compounds of animal shells and bone. Most of the mass of living organisms is oxygen as a component of water, the major constituent of lifeforms. Oxygen is continuously replenished in Earth's atmosphere by photosynthesis, which uses the energy of sunlight to produce oxygen from water and carbon dioxide.
Oxygen is too chemically reactive to remain a free element in air without being continuously replenished by the photosynthetic action of living organisms. Another form of oxygen, ozone absorbs ultraviolet UVB radiation and the high-altitude ozone layer helps protect the biosphere from ultraviolet radiation. However, ozone present at the surface is a byproduct of thus a pollutant. Oxygen was isolated by Michael Sendivogius before 1604, but it is believed that the element was discovered independently by Carl Wilhelm Scheele, in Uppsala, in 1773 or earlier, Joseph Priestley in Wiltshire, in 1774. Priority is given for Priestley because his work was published first. Priestley, called oxygen "dephlogisticated air", did not recognize it as a chemical element; the name oxygen was coined in 1777 by Antoine Lavoisier, who first recognized oxygen as a chemical element and characterized the role it plays in combustion. Common uses of oxygen include production of steel and textiles, brazing and cutting of steels and other metals, rocket propellant, oxygen therapy, life support systems in aircraft, submarines and diving.
One of the first known experiments on the relationship between combustion and air was conducted by the 2nd century BCE Greek writer on mechanics, Philo of Byzantium. In his work Pneumatica, Philo observed that inverting a vessel over a burning candle and surrounding the vessel's neck with water resulted in some water rising into the neck. Philo incorrectly surmised that parts of the air in the vessel were converted into the classical element fire and thus were able to escape through pores in the glass. Many centuries Leonardo da Vinci built on Philo's work by observing that a portion of air is consumed during combustion and respiration. In the late 17th century, Robert Boyle proved. English chemist John Mayow refined this work by showing that fire requires only a part of air that he called spiritus nitroaereus. In one experiment, he found that placing either a mouse or a lit candle in a closed container over water caused the water to rise and replace one-fourteenth of the air's volume before extinguishing the subjects.
From this he surmised that nitroaereus is consumed in both combustion. Mayow observed that antimony increased in weight when heated, inferred that the nitroaereus must have combined with it, he thought that the lungs separate nitroaereus from air and pass it into the blood and that animal heat and muscle movement result from the reaction of nitroaereus with certain substances in the body. Accounts of these and other experiments and ideas were published in 1668 in his work Tractatus duo in the tract "De respiratione". Robert Hooke, Ole Borch, Mikhail Lomonosov, Pierre Bayen all produced oxygen in experiments in the 17th and the 18th century but none of them recognized it as a chemical element; this may have been in part due to the prevalence of the philosophy of combustion and corrosion called the phlogiston theory, the favored explanation of those processes. Established in 1667 by the German alchemist J. J. Becher, modified by the chemist Georg Ernst Stahl by 1731, phlogiston theory stated that all combustible materials were made of two parts.
One part, called phlogiston, was given off when the substance containing it was burned, while the dephlogisticated part was thought to be its true form, or calx. Combustible materials that leave little residue, such as wood or coal, were thought to be made of phlogiston. Air did not play a role in phlogiston theory, nor were any initial quantitative experiments conducted to test the idea. Polish alchemist and physician Michael Sendivogius in his work De Lapide Philosophorum Tractatus duodecim e naturae fonte et manuali experientia depromti described a substance contained in air, referring to it as'cibus vitae', this substance is identical with oxygen. Sendivogius, during his experiments performed between 1598 and 1604, properly recognized that the substance is equivalent to the gaseous byproduct released by the thermal decomposition of potassium nitrate. In Bugaj’s view, the isolation of oxygen and the proper association of the substance to that part of air, required for life, lends sufficient weight to the discovery of oxygen by Sendivogius.
A hallucinogen is a psychoactive agent which can cause hallucinations, perceptual anomalies, other substantial subjective changes in thoughts and consciousness. The common types of hallucinogens are psychedelics 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 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 to the same substance.'Hallucinations' and'psychedelia' may both refer to the same aspects of subjective experience in a given instance.
The term psychedelia carries an added reference to psychedelic substance culture, and'psychedelics' are considered by many to be the'traditional' or'classical hallucinogens' including DMT, Psilocybin, LSD.'A hallucinogen' in this sense broadly refers to any substance which causes changes in perception or hallucinations, while psychedelics carry a positive connotation of general perceptual enhancement. In contrast to Hollister's 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. It is applied to any drug with perception-altering effects such as LSD and other ergotamine derivatives, DMT and other tryptamines including the alkaloids of Psilocybe spp. mescaline and other phenethylamines. The term "psychedelic" is applied somewhat interchangeably with "psychotomimetic" and "hallucinogen", The classical hallucinogens are considered to be the representative psychedelics and LSD is considered the prototypical psychedelic.
In order to refer to the LSD-like psychedelics, scientific authors have used the term "classical hallucinogen" in the sense defined by Glennon: "The classical hallucinogens are agents that meet Hollister's original definition, but are agents that: bind at 5-HT2 serotonin receptors, are recognized by animals trained to discriminate 1--2-aminopropane from vehicle. Otherwise, when the term "psychedelic" is used to refer only to the LSD-like psychedelics, authors explicitly point that they intend "psychedelic" to be understood according to this more restrictive interpretation. One explanatory model for the experiences provoked by psychedelics is the "reducing valve" concept, first articulated in Aldous Huxley's book The Doors of Perception. In this view, the drugs disable the brain's "filtering" ability to selectively prevent certain perceptions, emotions and thoughts from reaching the conscious mind; this effect has been described as mind expanding, or consciousness expanding, for the drug "expands" the realm of experience available to conscious awareness.
While possessing a unique mechanism of action, cannabis or marijuana has been regarded alongside the classic psychedelics. A designer drug is a structural or functional analog of a controlled substance, designed to mimic the pharmacological effects of the original drug while at the same time avoid being classified as illegal and/or avoid detection in standard drug tests. Many designer drugs and research chemicals are hallucinogenic in nature, such as those in the 2C and 25-NB families. Dissociatives produce analgesia and catalepsy at anesthetic doses, they produce a sense of detachment from the surrounding environment, hence "the state has been designated as dissociative anesthesia since the patient seems disassociated from his environment." Dissociative symptoms include the disruption or compartmentalization of "...the integrated functions of consciousness, identity or perception."p. 523 Dissociation of sensory input can cause derealization, the perception of the outside world as being dream-like or unreal.
Other dissociative experiences include depersonalization, which includes feeling detached from one's body. Simeon offered "...common descriptions of depersonalisation experiences: watching oneself from a distance. However, dissociation is remarkably administered by salvinorin A's potent κ-opioid receptor agonism, though sometimes described as an atypical psychedelic; some dissociatives can have CNS depressant effects, thereby carrying similar risks as opioids, which can slow breathing or heart rate to levels resulting in death (w
The United States of America known as the United States or America, is a country composed of 50 states, a federal district, five major self-governing territories, various possessions. At 3.8 million square miles, the United States is the world's third or fourth largest country by total area and is smaller than the entire continent of Europe's 3.9 million square miles. With a population of over 327 million people, the U. S. is the third most populous country. The capital is Washington, D. C. and the largest city by population is New York City. Forty-eight states and the capital's federal district are contiguous in North America between Canada and Mexico; the State of Alaska is in the northwest corner of North America, bordered by Canada to the east and across the Bering Strait from Russia to the west. The State of Hawaii is an archipelago in the mid-Pacific Ocean; the U. S. territories are scattered about the Pacific Ocean and the Caribbean Sea, stretching across nine official time zones. The diverse geography and wildlife of the United States make it one of the world's 17 megadiverse countries.
Paleo-Indians migrated from Siberia to the North American mainland at least 12,000 years ago. European colonization began in the 16th century; the United States emerged from the thirteen British colonies established along the East Coast. Numerous disputes between Great Britain and the colonies following the French and Indian War led to the American Revolution, which began in 1775, the subsequent Declaration of Independence in 1776; the war ended in 1783 with the United States becoming the first country to gain independence from a European power. The current constitution was adopted in 1788, with the first ten amendments, collectively named the Bill of Rights, being ratified in 1791 to guarantee many fundamental civil liberties; the United States embarked on a vigorous expansion across North America throughout the 19th century, acquiring new territories, displacing Native American tribes, admitting new states until it spanned the continent by 1848. During the second half of the 19th century, the Civil War led to the abolition of slavery.
By the end of the century, the United States had extended into the Pacific Ocean, its economy, driven in large part by the Industrial Revolution, began to soar. The Spanish–American War and World War I confirmed the country's status as a global military power; the United States emerged from World War II as a global superpower, the first country to develop nuclear weapons, the only country to use them in warfare, a permanent member of the United Nations Security Council. Sweeping civil rights legislation, notably the Civil Rights Act of 1964, the Voting Rights Act of 1965 and the Fair Housing Act of 1968, outlawed discrimination based on race or color. During the Cold War, the United States and the Soviet Union competed in the Space Race, culminating with the 1969 U. S. Moon landing; the end of the Cold War and the collapse of the Soviet Union in 1991 left the United States as the world's sole superpower. The United States is the world's oldest surviving federation, it is a representative democracy.
The United States is a founding member of the United Nations, World Bank, International Monetary Fund, Organization of American States, other international organizations. The United States is a developed country, with the world's largest economy by nominal GDP and second-largest economy by PPP, accounting for a quarter of global GDP; the U. S. economy is post-industrial, characterized by the dominance of services and knowledge-based activities, although the manufacturing sector remains the second-largest in the world. The United States is the world's largest importer and the second largest exporter of goods, by value. Although its population is only 4.3% of the world total, the U. S. holds 31% of the total wealth in the world, the largest share of global wealth concentrated in a single country. Despite wide income and wealth disparities, the United States continues to rank high in measures of socioeconomic performance, including average wage, human development, per capita GDP, worker productivity.
The United States is the foremost military power in the world, making up a third of global military spending, is a leading political and scientific force internationally. In 1507, the German cartographer Martin Waldseemüller produced a world map on which he named the lands of the Western Hemisphere America in honor of the Italian explorer and cartographer Amerigo Vespucci; the first documentary evidence of the phrase "United States of America" is from a letter dated January 2, 1776, written by Stephen Moylan, Esq. to George Washington's aide-de-camp and Muster-Master General of the Continental Army, Lt. Col. Joseph Reed. Moylan expressed his wish to go "with full and ample powers from the United States of America to Spain" to seek assistance in the revolutionary war effort; the first known publication of the phrase "United States of America" was in an anonymous essay in The Virginia Gazette newspaper in Williamsburg, Virginia, on April 6, 1776. The second draft of the Articles of Confederation, prepared by John Dickinson and completed by June 17, 1776, at the latest, declared "The name of this Confederation shall be the'United States of America'".
The final version of the Articles sent to the states for ratification in late 1777 contains the sentence "The Stile of this Confederacy shall be'The United States of America'". In June 1776, Thomas Jefferson wrote the phrase "UNITED STATES OF AMERICA" in all capitalized letters in the headline of his "original Rough draught" of the Declaration of Independence; this draft of the document did not surface unti
N,N-Dimethyltryptamine is a chemical substance that occurs in many plants and animals and, both a derivative and a structural analog of tryptamine. It can be consumed as a psychedelic drug and has been prepared by various cultures for ritual purposes as an entheogen. Rick Strassman labeled it "the spirit molecule". DMT is illegal in most countries. DMT has a rapid onset, intense effects and a short duration of action. For those reasons, DMT was known as the "businessman's trip" during the 1960s in the United States, as a user could access the full depth of a psychedelic experience in less time than with other substances such as LSD or magic mushrooms. DMT can be inhaled, vaporized or ingested, its effects depend on the dose; when inhaled or injected, the effects last a short period of time: about 5 to 15 minutes. Effects can last 3 hours or more when orally ingested along with an MAOI, such as the ayahuasca brew of many native Amazonian tribes. DMT can produce vivid "projections" of mystical experiences involving euphoria and dynamic hallucinations of geometric forms.
DMT is a functional analog and structural analog of other psychedelic tryptamines such as 4-AcO-DMT, 5-MeO-DMT, 5-HO-DMT, psilocin. The structure of DMT occurs within some important biomolecules like serotonin and melatonin, making them structural analogs of DMT. DMT is produced in many species of plants in conjunction with its close chemical relatives 5-methoxy-N,N-dimethyltryptamine and bufotenin. DMT-containing plants are used in South American shamanic practices, it is one of the main active constituents of the drink ayahuasca. It occurs as the primary psychoactive alkaloid in several plants including Mimosa tenuiflora, Diplopterys cabrerana, Psychotria viridis. DMT is found as a minor alkaloid in snuff made from Virola bark resin in which 5-MeO-DMT is the main active alkaloid. DMT is found as a minor alkaloid in bark and beans of Anadenanthera peregrina and Anadenanthera colubrina used to make Yopo and Vilca snuff in which bufotenin is the main active alkaloid. Psilocin and its precursor psilocybin, an active chemical in many psychedelic mushrooms, are structurally similar to DMT.
The psychotropic effects of DMT were first studied scientifically by the Hungarian chemist and psychologist Dr. Stephen Szára, who performed research with volunteers in the mid-1950s. Szára, who worked for the US National Institutes of Health, had turned his attention to DMT after his order for LSD from the Swiss company Sandoz Laboratories was rejected on the grounds that the powerful psychotropic could be dangerous in the hands of a communist country. DMT is not active orally unless it is combined with a monoamine oxidase inhibitor such as a reversible inhibitor of monoamine oxidase A, for example, harmaline. Without an MAOI, the body metabolizes orally administered DMT, it therefore has no hallucinogenic effect unless the dose exceeds monoamine oxidase's metabolic capacity. Other means of ingestion such as vaporizing, injecting, or insufflating the drug can produce powerful hallucinations for a short time, as the DMT reaches the brain before it can be metabolized by the body's natural monoamine oxidase.
Taking a MAOI prior to vaporizing or injecting DMT potentiates the effects. Several scientific experimental studies have tried to measure subjective experiences of altered states of consciousness induced by drugs under controlled and safe conditions. In the 1990s, Rick Strassman and his colleagues conducted a five-year-long DMT study at the University of New Mexico; the results provided insight about the quality of subjective psychedelic experiences. In this study participants received the DMT dosage intravenously via injection and the findings suggested that different psychedelic experiences can occur, depending on the level of dosage. Lower doses produced emotional responses, but not hallucinogenic experiences. In contrast, responses produced by higher doses researchers labeled as "hallucinogenic" that elicited "intensely colored moving display of visual images, abstract or both". Comparing to other sensory modalities the most affected was visual domain. Participants reported visual hallucinations, less auditory hallucinations and specific physical sensation progressing to a sense of bodily dissociation, as well as experiences of euphoria, calm and anxiety.
Strassman stressed the importance of the context where the drug has been taken. He claimed that DMT has no beneficial effects of itself, rather the context when and where people take it plays an important role, it appears. It can induce a state or feeling to a person that he or she is able to "communicate with other intelligent-life forms". High doses of DMT produce a hallucinatory state that involves sense of "another intelligence" that people sometimes describe as "super-intelligent", but "emotionally detached". In 1995 Adolf Dittrich and Daniel Lamparter did a study where they found that DMT-induced altered state of consciousness is influenced by habitual, rather than situative factors. In the study researchers used three dimensions of the APZ questionnaire to describe ASC. First, oceanic boundlessness refers to dissolution of ego boundaries associated with positive emotions. Second, anxious ego-dissolution includes disorder of thoughts, loss of autonomy and self-control
Simplified molecular-input line-entry system
The simplified molecular-input line-entry system is a specification in the form of a line notation for describing the structure of chemical species using short ASCII strings. SMILES strings can be imported by most molecule editors for conversion back into two-dimensional drawings or three-dimensional models of the molecules; the original SMILES specification was initiated in the 1980s. It has since been extended. In 2007, an open standard called. Other linear notations include the Wiswesser line notation, ROSDAL, SYBYL Line Notation; the original SMILES specification was initiated by David Weininger at the USEPA Mid-Continent Ecology Division Laboratory in Duluth in the 1980s. Acknowledged for their parts in the early development were "Gilman Veith and Rose Russo and Albert Leo and Corwin Hansch for supporting the work, Arthur Weininger and Jeremy Scofield for assistance in programming the system." The Environmental Protection Agency funded the initial project to develop SMILES. It has since been modified and extended by others, most notably by Daylight Chemical Information Systems.
In 2007, an open standard called "OpenSMILES" was developed by the Blue Obelisk open-source chemistry community. Other'linear' notations include the Wiswesser Line Notation, ROSDAL and SLN. In July 2006, the IUPAC introduced the InChI as a standard for formula representation. SMILES is considered to have the advantage of being more human-readable than InChI; the term SMILES refers to a line notation for encoding molecular structures and specific instances should be called SMILES strings. However, the term SMILES is commonly used to refer to both a single SMILES string and a number of SMILES strings; the terms "canonical" and "isomeric" can lead to some confusion when applied to SMILES. The terms are not mutually exclusive. A number of valid SMILES strings can be written for a molecule. For example, CCO, OCC and CC all specify the structure of ethanol. Algorithms have been developed to generate the same SMILES string for a given molecule; this SMILES is unique for each structure, although dependent on the canonicalization algorithm used to generate it, is termed the canonical SMILES.
These algorithms first convert the SMILES to an internal representation of the molecular structure. Various algorithms for generating canonical SMILES have been developed and include those by Daylight Chemical Information Systems, OpenEye Scientific Software, MEDIT, Chemical Computing Group, MolSoft LLC, the Chemistry Development Kit. A common application of canonical SMILES is indexing and ensuring uniqueness of molecules in a database; the original paper that described the CANGEN algorithm claimed to generate unique SMILES strings for graphs representing molecules, but the algorithm fails for a number of simple cases and cannot be considered a correct method for representing a graph canonically. There is no systematic comparison across commercial software to test if such flaws exist in those packages. SMILES notation allows the specification of configuration at tetrahedral centers, double bond geometry; these are structural features that cannot be specified by connectivity alone and SMILES which encode this information are termed isomeric SMILES.
A notable feature of these rules is. The term isomeric SMILES is applied to SMILES in which isotopes are specified. In terms of a graph-based computational procedure, SMILES is a string obtained by printing the symbol nodes encountered in a depth-first tree traversal of a chemical graph; the chemical graph is first trimmed to remove hydrogen atoms and cycles are broken to turn it into a spanning tree. Where cycles have been broken, numeric suffix labels are included to indicate the connected nodes. Parentheses are used to indicate points of branching on the tree; the resultant SMILES form depends on the choices: of the bonds chosen to break cycles, of the starting atom used for the depth-first traversal, of the order in which branches are listed when encountered. Atoms are represented by the standard abbreviation of the chemical elements, in square brackets, such as for gold. Brackets may be omitted in the common case of atoms which: are in the "organic subset" of B, C, N, O, P, S, F, Cl, Br, or I, have no formal charge, have the number of hydrogens attached implied by the SMILES valence model, are the normal isotopes, are not chiral centers.
All other elements must be enclosed in brackets, have charges and hydrogens shown explicitly. For instance, the SMILES for water may be written as either O or. Hydrogen may be written as a separate atom; when brackets are used, the symbol H is added if the atom in brackets is bonded to one or more hydrogen, followed by the number of hydrogen atoms if greater than 1 by the sign + for a positive charge or by - for a negative charge. For example, for ammonium. If there is more than one charge, it is written as digit.
Sensory nervous system
The sensory nervous system is a part of the nervous system responsible for processing sensory information. A sensory system consists of sensory neurons, neural pathways, parts of the brain involved in sensory perception. Recognized sensory systems are those for vision, touch, taste and balance. In short, senses are transducers from the physical world to the realm of the mind where we interpret the information, creating our perception of the world around us. Organisms need information to solve at least three kinds of problems: to maintain an appropriate environment, i.e. homeostasis. Organisms need to transmit information in order to influence another's behavior: to identify themselves, warn conspecifics of danger, coordinate activities, or deceive; the receptive field is the area of the body or environment to which a receptor organ and receptor cells respond. For instance, the part of the world an eye can see, is its receptive field. Receptive fields have been identified for the visual system, auditory system and somatosensory system.
Sensory systems code for four aspects of a stimulus. Arrival time of a sound pulse and phase differences of continuous sound are used for sound localization. Certain receptors are sensitive to certain types of stimuli. Receptors send impulses in certain patterns to send information about the intensity of a stimulus; the location of the receptor, stimulated gives the brain information about the location of the stimulus. The duration of the stimulus is conveyed by firing patterns of receptors; these impulses are transmitted to the brain through afferent neurons. While debate exists among neurologists as to the specific number of senses due to differing definitions of what constitutes a sense, Gautama Buddha and Aristotle classified five ‘traditional’ human senses which have become universally accepted: touch, smell and hearing. Other senses that have been well-accepted in most mammals, including humans, include nociception, equilibrioception and thermoception. Furthermore, some nonhuman animals have been shown to possess alternate senses, including magnetoception and electroreception.
The initialization of sensation stems from the response of a specific receptor to a physical stimulus. The receptors which react to the stimulus and initiate the process of sensation are characterized in four distinct categories: chemoreceptors, photoreceptors and thermoreceptors. All receptors receive distinct physical stimuli and transduce the signal into an electrical action potential; this action potential travels along afferent neurons to specific brain regions where it is processed and interpreted. Chemoreceptors, or chemosensors, detect certain chemical stimuli and transduce that signal into an electrical action potential; the two primary types of chemoreceptors are: Distance chemoreceptors are integral to receiving stimuli in the olfactory system through both olfactory receptor neurons and neurons in the vomeronasal organ. Direct chemoreceptors include the taste buds in the gustatory system as well as receptors in the aortic bodies which detect changes in oxygen concentration. Photoreceptors are capable of phototransduction, a process which converts light into, among other types of energy, a membrane potential.
The three primary types of photoreceptors are: Cones are photoreceptors which respond to color. In humans the three different types of cones correspond with a primary response to short wavelength, medium wavelength, long wavelength. Rods are photoreceptors which are sensitive to the intensity of light, allowing for vision in dim lighting; the concentrations and ratio of rods to cones is correlated with whether an animal is diurnal or nocturnal. In humans rods outnumber cones by 20:1, while in nocturnal animals, such as the tawny owl, the ratio is closer to 1000:1. Ganglion Cells reside in the adrenal medulla and retina where they are involved in the sympathetic response. Of the ~1.3 million ganglion cells present in the retina, 1-2% are believed to be photosensitive ganglia. These photosensitive ganglia play a role in conscious vision for some animals, are believed to do the same in humans. Mechanoreceptors are sensory receptors which respond to mechanical forces, such as pressure or distortion.
While mechanoreceptors are present in hair cells and play an integral role in the vestibular and auditory systems, the majority of mechanoreceptors are cutaneous and are grouped into four categories: Slowly adapting type 1 receptors have small receptive fields and respond to static stimulation. These receptors are used in the sensations of form and roughness. Adapting type 2 receptors have large receptive fields and respond to stretch. To type 1, they produce sustained responses to a continued stimuli. Adapting receptors have small receptive fields and underlie the perception of slip. Pacinian receptors have large receptive fields and are the predominant receptors for high-frequency vibration. Thermoreceptors are sensory receptors which respond to