|
Odorless
The sense of smell, or olfaction, is the special sense through which smells (or odors) are perceived. The sense of smell has many functions, including detecting desirable foods, hazards, and pheromones, and plays a role in taste. In humans, it occurs when an odor binds to a receptor within the nasal cavity, transmitting a signal through the olfactory system. Glomeruli aggregate signals from these receptors and transmit them to the olfactory bulb, where the sensory input will start to interact with parts of the brain responsible for smell identification, memory, and emotion. There are many different causes for alteration, lack, or disturbance to a normal sense of smell, and can include damage to the nose or smell receptors, or central problems affecting the brain. Some causes include upper respiratory infections, traumatic brain injury, and neurodegenerative disease. History of study Early scientific study of the sense of smell includes the extensive doctoral dissertation o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Odor
An odor (American English) or odour (English in the Commonwealth of Nations, Commonwealth English; American and British English spelling differences#-our, -or, see spelling differences) is caused by one or more volatilized chemical compounds that are generally found in low concentrations that humans and animals can perceive via their sense of Sense of smell, smell. An odor is also called a "smell" or a "scent", which can refer to either a pleasant or an unpleasant odor. While "odor" and "smell" can refer to pleasant and unpleasant odors, the terms "scent", "aroma", and "fragrance" are usually reserved for pleasant-smelling odors and are frequently used in the food and cosmetic industry to describe floral scents or to refer to perfumes. Physiology of smell Sense of smell The perception of odors, or sense of smell, is mediated by the olfactory nerve. The olfactory receptor (OR) cells are neurons present in the olfactory epithelium, which is a small patch of tissue at th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pheromone
A pheromone () is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting like hormones outside the body of the secreting individual, to affect the behavior of the receiving individuals. There are ''alarm signal, alarm pheromones'', ''food trail pheromones'', ''sex pheromones'', and many others that affect behavior or physiology. Pheromones are used by many organisms, from basic unicellular prokaryotes to complex multicellular eukaryotes. Their use among insects has been particularly well documented. In addition, some vertebrates, plants and ciliates communicate by using pheromones. The ecological functions and evolution of pheromones are a major topic of research in the field of chemical ecology. Background The portmanteau word "pheromone" was coined by Peter Karlson and Martin Lüscher in 1959, based on the Greek φερω ''pheroo'' ('I carry') and ὁρμων ''hormon'' ('stimulating'). P ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carnation
''Dianthus caryophyllus'' (), commonly known as the carnation or clove pink, is a species of ''Dianthus''. It is likely native to the Mediterranean region but its exact range is unknown due to extensive cultivation for the last 2,000 years.Med-Checklist''Dianthus caryophyllus''/ref>Flora Europaea''Dianthus caryophyllus''/ref>Blamey, M. & Grey-Wilson, C. (1989). ''Flora of Britain and Northern Europe''. Huxley, A., ed. (1992). ''New RHS Dictionary of Gardening''. Macmillan . Taxonomy Carnations were mentioned in Greek literature 2,000 years ago. The term ''dianthus'' was coined by Greek botanist Theophrastus, and is derived from the Ancient Greek words for divine ("dios") and flower ("anthos"). The name "carnation" is believed to come from the Latin ''corona-ae'', a "wreath, garland, chaplet, crown",Cassell's Latin Dictionary, Marchant, J.R.V, & Charles, Joseph F., (Eds.), Revised Edition, 1928 as it was one of the flowers used in Greek and Roman ceremonial crowns, or possibly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Upper Respiratory Tract Infection
An upper respiratory tract infection (URTI) is an illness caused by an acute infection, which involves the upper respiratory tract, including the nose, sinuses, pharynx, larynx or trachea. This commonly includes nasal obstruction, sore throat, tonsillitis, pharyngitis, laryngitis, sinusitis, otitis media, and the common cold. Most infections are viral in nature, and in other instances, the cause is bacterial. URTIs can also be fungal or helminthic in origin, but these are less common. In 2015, 17.2 billion cases of URTIs are estimated to have occurred. As of 2014, they caused about 3,000 deaths, down from 4,000 in 1990. Signs and symptoms In uncomplicated colds, coughing and nasal discharge may persist for 14 days or more even after other symptoms have resolved. Acute URTIs include rhinitis, pharyngitis/tonsillitis, and laryngitis often referred to as a common cold, and their complications: sinusitis, ear infection, and sometimes bronchitis (though bronchi are generally cl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Olfactory Receptors
Olfactory receptors (ORs), also known as odorant receptors, are chemoreceptors expressed in the cell membranes of olfactory receptor neurons and are responsible for the detection of odorants (for example, compounds that have an odor) which give rise to the sense of smell. Activated olfactory receptors trigger nerve impulses which transmit information about odor to the brain. These receptors are members of the class A rhodopsin-like family of G protein-coupled receptors (GPCRs). The olfactory receptors form a multigene family consisting of around 800 genes in humans and 1400 genes in mice. Expression In vertebrates, the olfactory receptors are located in both the cilia and synapses of the olfactory sensory neurons and in the epithelium of the human airway. In insects, olfactory receptors are located on the antennae and other chemosensory organs. Sperm cells also express odor receptors, which are thought to be involved in chemotaxis to find the egg cell. Mechanism Rather ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gene
In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a basic unit of heredity and the molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protein-coding genes and noncoding genes. During gene expression, the DNA is first copied into RNA. The RNA can be directly functional or be the intermediate template for a protein that performs a function. The transmission of genes to an organism's offspring is the basis of the inheritance of phenotypic traits. These genes make up different DNA sequences called genotypes. Genotypes along with environmental and developmental factors determine what the phenotypes will be. Most biological traits are under the influence of polygenes (many different genes) as well as gen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mammals
Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or hair, and three middle ear bones. These characteristics distinguish them from reptiles (including birds) from which they diverged in the Carboniferous, over 300 million years ago. Around 6,400 extant species of mammals have been described divided into 29 orders. The largest orders, in terms of number of species, are the rodents, bats, and Eulipotyphla (hedgehogs, moles, shrews, and others). The next three are the Primates (including humans, apes, monkeys, and others), the Artiodactyla ( cetaceans and even-toed ungulates), and the Carnivora (cats, dogs, seals, and others). In terms of cladistics, which reflects evolutionary history, mammals are the only living members of the Synapsida (synapsids); this clade, together with Saur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nobel Prize
The Nobel Prizes ( ; sv, Nobelpriset ; no, Nobelprisen ) are five separate prizes that, according to Alfred Nobel's will of 1895, are awarded to "those who, during the preceding year, have conferred the greatest benefit to humankind." Alfred Nobel was a Swedish chemist, engineer, and industrialist most famously known for the invention of dynamite. He died in 1896. In his will, he bequeathed all of his "remaining realisable assets" to be used to establish five prizes which became known as "Nobel Prizes." Nobel Prizes were first awarded in 1901. Nobel Prizes are awarded in the fields of Physics, Chemistry, Physiology or Medicine, Literature, and Peace (Nobel characterized the Peace Prize as "to the person who has done the most or best to advance fellowship among nations, the abolition or reduction of standing armies, and the establishment and promotion of peace congresses"). In 1968, Sveriges Riksbank (Sweden's central bank) funded the establishment of the Prize in Economi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Richard Axel
Richard Axel (born July 2, 1946) is an American molecular biologist and university professor in the Department of Neuroscience at Columbia University and investigator at the Howard Hughes Medical Institute. His work on the olfactory system won him and Linda Buck, a former postdoctoral research scientist in his group, the Nobel Prize in Physiology or Medicine in 2004. Education and early life Born in New York City to Polish Jewish immigrants, Axel grew up in Brooklyn. He graduated from Stuyvesant High School in 1963,(along with Bruce Bueno de Mesquita and Alexander Rosenberg), received his B.A. in 1967 from Columbia University, and his M.D. in 1971 from Johns Hopkins University. He returned to Columbia later that year and eventually became a full professor in 1978. Research and career During the late 1970s, Axel, along with microbiologist Saul J. Silverstein and geneticist Michael H. Wigler, discovered a technique of cotransformation via transfection, a process which allows ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Linda B
Linda may refer to: As a name * Linda (given name), a female given name (including a list of people and fictional characters so named) * Linda (singer) (born 1977), stage name of Svetlana Geiman, a Russian singer * Anita Linda (born Alice Lake in 1924), Filipino film actress * Bogusław Linda (born 1952), Polish actor * Solomon Linda (1909–1962), South African Zulu musician, singer and composer who wrote the song "Mbube" which later became "The Lion Sleeps Tonight" Places * Linda, California, a census-designated place * Linda, Missouri, a ghost town * Linda, Tasmania, Australia, a ghost town * Linda, Georgia, village in Abkhazia, Georgia * Linda, Bashkortostan, village in Bashkortostan, Russia * Linda Valley, Tasmania * 7169 Linda, an asteroid * Linda, a small lunar crater - see Delisle (crater) Music * ''Linda'' (Linda George album), 1974 * ''Linda'' (Linda Clifford album), 1977 * ''Linda'' (Miguel Bosé album), 1978 ** "Linda" (Miguel Bosé song), the title song * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lucretius
Titus Lucretius Carus ( , ; – ) was a Roman poet and philosopher. His only known work is the philosophical poem ''De rerum natura'', a didactic work about the tenets and philosophy of Epicureanism, and which usually is translated into English as ''On the Nature of Things''—and somewhat less often as ''On the Nature of the Universe''. Lucretius has been credited with originating the concept of the three-age system that was formalised in 1836 by C. J. Thomsen. Very little is known about Lucretius's life; the only certainty is that he was either a friend or client of Gaius Memmius, to whom the poem was addressed and dedicated. ''De rerum natura'' was a considerable influence on the Augustan poets, particularly Virgil (in his ''Aeneid'' and ''Georgics'', and to a lesser extent on the ''Eclogues'') and Horace. The work was almost lost during the Middle Ages, but was rediscovered in 1417 in a monastery in Germany by Poggio Bracciolini and it played an important role both ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stimulus Modality
Stimulus modality, also called sensory modality, is one aspect of a stimulus or what is perceived after a stimulus. For example, the temperature modality is registered after heat or cold stimulate a receptor. Some sensory modalities include: light, sound, temperature, taste, pressure, and smell. The type and location of the sensory receptor activated by the stimulus plays the primary role in coding the sensation. All sensory modalities work together to heighten stimuli sensation when necessary. Multimodal perception Multimodal perception is the ability of the mammalian nervous system to combine all of the different inputs of the sensory nervous system to result in an enhanced detection or identification of a particular stimulus. Combinations of all sensory modalities are done in cases where a single sensory modality results in ambiguous and incomplete result. Integration of all sensory modalities occurs when multimodal neurons receive sensory information which overlaps with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
