NationMaster - Encyclopedia: Olfactory tubercle

Olfaction, the sense of smell, is the detection of chemicals dissolved in air. The chemicals themselves, generally at very low concentrations, are called odors. Image File history File links Download high-resolution version (2914x2078, 740 KB) Created by Veracious Rey, added to Wikipedia 12/2006. ... Image File history File links Download high-resolution version (2914x2078, 740 KB) Created by Veracious Rey, added to Wikipedia 12/2006. ... Senses are the physiological methods of perception. ... Look up smell in Wiktionary, the free dictionary. ... Odor receptors on the antennae of a Luna moth An odor or odour (see spelling differences) is a chemical dissolved in air, generally at a very low concentration, which we perceive by the sense of olfaction. ...

How olfaction works

As discovered by Linda B. Buck and Richard Axel (who were awarded the Nobel Prize in 2004), mammals have about a thousand genes for odor reception.^[1] Of these genes, only a portion are functional odor receptors. Humans have 347 functional odor receptor genes; the other genes have nonsense mutations. This number was determined by analyzing the genome in the Human Genome Project; the number may vary among strains, and does vary among individual humans (see anosmia). For example, not all humans can smell androstenone, a component of male sweat (and minor component of female one). Linda B. Buck, Ph. ... Richard Axel, M.D. (born July 2, 1946, New York City) is an American scientist whose work on the olfactory system won him and Linda B. Buck, a former post-doctoral scientist in his research group, the Nobel Prize in Physiology or Medicine in 2004. ... Nobel Prize medal. ... Orders Subclass Monotremata Monotremata Subclass Marsupialia Didelphimorphia Paucituberculata Microbiotheria Dasyuromorphia Peramelemorphia Notoryctemorphia Diprotodontia Subclass Placentalia Xenarthra Dermoptera Desmostylia Scandentia Primates Rodentia Lagomorpha Insectivora Chiroptera Pholidota Carnivora Perissodactyla Artiodactyla Cetacea Afrosoricida Macroscelidea Tubulidentata Hyracoidea Proboscidea Sirenia The mammals are the class of vertebrate animals primarily characterized by the presence of mammary... For other meanings of this term, see gene (disambiguation). ... Olfactory receptors are a type of G protein-coupled receptor in olfactory receptor neurons. ... Odor receptors on the antennae of a Luna moth An odor or odour (see spelling differences) is a chemical dissolved in air, generally at a very low concentration, which we perceive by the sense of olfaction. ... Receptor may refer to: In telecommunication, a receiver. ... For other meanings of this term, see gene (disambiguation). ... In genetics, a nonsense mutation is a point mutation in a sequence of DNA that results in a premature stop codon (also called a nonsense codon) in the transcribed mRNA, and possibly a truncated (and often nonfunctional) protein product. ... In biology the genome of an organism is the whole hereditary information of an organism that is encoded in the DNA (or, for some viruses, RNA). ... The Human Genome Project (HGP) is a project to de-code (i. ... Anosmia is the lack of olfactory, or a loss of the ability to smell. ... Androsterone (5a-androst-16-en-3-one) is a steroid found in male sweat. ...

Each olfactory receptor neuron in the nose expresses only one functional odor receptor. Odor receptor nerve cells function like a key-lock system: if the airborne molecules of a certain chemical can fit into the lock the nerve cell will respond. According to shape theory, each receptor detects a feature of the odor molecule. Weak-shape theory, known as odotope theory, suggests that different receptors detect only small pieces of molecules, and these minimal inputs are combined to form a larger olfactory perception (similar to the way visual perception is built up of smaller, information-poor sensations, combined and refined to create a detailed overall perception). An alternative theory, the vibration theory proposed by Luca Turin^[2]^[3], posits that odor receptors detect the frequencies of vibrations of odor molecules in the infrared range by electron tunnelling. However, the behavioral predictions of this theory have been called into question.^[4] As of yet, there is no theory that explains human olfactory perception completely. An olfactory receptor neuron, also called an olfactory sensory neuron, is the primary transduction cell for olfaction in the olfactory system. ... Human nose in profile A typical bulbous human nose Anatomically, a nose is a protuberance in vertebrates that houses the nostrils, or nares, which admit and expel air for respiration. ... The Shape theory of smell states that the sensation of smell is due to a lock and key mechanism by which a scent molecule fits into a receptor site in the nose. ... In chemistry, a molecule is an aggregate of two or more atoms in a definite arrangement held together by chemical bonds [1] [2] [3] [4] [5]. Chemical substances are not infinitely divisible into smaller fractions of the same substance: a molecule is generally considered the smallest particle of a pure... Odotope Theory, also known as Weak-Shape Theory, is a leading neurophysiological theory of how the sense of smell functions. ... According to this theory the sensation of smell arises from the noses sensing of the rate of electron tunneling into the scent molecule. ... Luca Turin (1953 - ) is a biophysicist with a long-standing interest in scent, fragrance and the perfume industry. ... Quantum tunneling is the quantum-mechanical effect of transitioning through a classically-forbidden energy state. ...

Olfactory epithelium

In vertebrates smells are sensed by olfactory sensory neurons in the olfactory epithelium. The proportion of olfactory epithelium compared to respiratory epithelium (not innervated) gives an indication of the animals olfactory sensitivity. Humans have about 2*4 cm² of olfactory epithelium, whereas some dogs have 150 cm². A dog's olfactory epithelium is also considerably more densely innervated, with a hundred times more receptors per square centimetre. Classes and Clades See below Male and female Superb Fairy-wren Vertebrates are members of the subphylum Vertebrata (within the phylum Chordata), specifically, those chordates with backbones or spinal columns. ... An olfactory receptor neuron, also called an olfactory sensory neuron, is the primary transduction cell for olfaction in the olfactory system. ... The olfactory epithelium is a specialized epithelial tissue inside the nasal cavity that is involved in smell. ... Types of epithelium This article discusses the epithelium, an animal anatomical structure. ...

Molecules of odorands passing through the superior nasal concha of the nasal passages dissolve in the mucus lining the superior portion of the cavity and are detected by olfactory receptors on the dendrites of the olfactory sensory neurons. This may occur by diffusion or by the binding of the odorant to odorant binding proteins. The mucus overlying the epithelium contains mucopolysaccharides, salts, enzymes and antibodies (these are highly important as the olfactory neurons provide a direct passage for infection to pass to the brain). The back part of the medial surface of the labyrinth of ethmoid is subdivided by a narrow oblique fissure, the superior meatus of the nose, bounded above by a thin, curved plate, the superior nasal concha. ... Mucus is a slippery secretion of the lining of various membranes in the body (mucous membranes). ... Olfactory receptors are a type of G protein-coupled receptor in olfactory receptor neurons. ... In biology, a dendrite is a slender, typically branched projection of a nerve cell, or neuron, which conducts the electrical stimulation received from other cells to the body or soma of the cell from which it projects. ... Glycosaminoglycans (GAGs) are long unbranched polysaccharides, made up of repeating disaccharides that may be sulphated (e. ... Neuraminidase ribbon diagram An enzyme (in Greek en = in and zyme = blend) is a protein, or protein complex, that catalyzes a chemical reaction and also controls the 3D orientation of the catalyzed substrates. ... Wikipedia does not yet have an article with this exact name. ... For more specific information about the human brain, see its main article at human brain A sketch of the human brain by artist Priyan Weerappuli, imposed upon his sketch of the profile of Michaelangelos David In animals, the brain, or encephalon (Greek for in the head), is the control...

Receptor neuron

The process of how the binding of the ligand (odor molecule or odorant) to the receptor leads to an action potential in the receptor neuron is via a second messenger pathway depending on the organism. In mammals the odorants stimulate adenylate cyclase to synthesize cAMP via a G protein called G_olf. cAMP, which is the second messenger here, opens a cyclic nucleotide-gated ion channel (CNG) producing an influx of cations (largely Ca²⁺ with some Na⁺) into the cell, slightly depolarising it. The Ca²⁺ in turn opens a Ca²⁺ activated chloride channel leading to efflux of Cl^-, further depolarising the cell and triggering an action potential. Ca²⁺ is then extruded through a sodium-calcium exchanger. A calcium-calmodulin complex also acts to inhibit the binding of cAMP to the cAMP dependent channel, thus contributing to olfactory adaptation. This mechanism of transduction is somewhat unique, in that cAMP works by directly binding to the ion channel rather than through activation of protein kinase A. It is similar to the transduction mechanism for photoreceptors in which the second messenger cGMP works by directly binding to ion channels, suggesting that maybe one of these receptors was evolutionarily adapted into the other. There are also considerable similarities in the immediate processing of stimuli by lateral inhibition. In chemistry, a ligand is an atom, ion, or molecule (see also: functional group) that generally donates one or more of its electrons through a coordinate covalent bond to, or shares its electrons through a covalent bond with, one or more central atoms or ions (these ligands act as a... A. A schematic view of an idealized action potential illustrates its various phases as the action potential passes a point on a cell membrane. ... In biology, second messengers are low-weight diffusible molecules that are used in signal transduction to relay signals within a cell. ... Adenylate cyclase Adenylate cyclase (EC 4. ... Structure of cAMP cAMP represented in three ways, the left with sticks-representation, the middle with structure formula, and the right with space filled representation. ... G-proteins, short for guanine nucleotide binding proteins, are a family of proteins involved in second messenger cascades. ... A Cyclic nucleotide-gated ion channel is any ion channel that opens in the presence of cyclic nucleotides. ... A cation is an ion with positive charge. ... General Name, Symbol, Number calcium, Ca, 20 Chemical series alkaline earth metals Group, Period, Block 2, 4, s Appearance silvery white Atomic mass 40. ... General Name, Symbol, Number sodium, Na, 11 Chemical series alkali metals Group, Period, Block 1, 3, s Appearance silvery white Atomic mass 22. ... Ion channels are present in the membranes that surround all biological cells. ... General Name, Symbol, Number chlorine, Cl, 17 Chemical series halogens Group, Period, Block 17, 3, p Appearance yellowish green Atomic mass 35. ... A. A schematic view of an idealized action potential illustrates its various phases as the action potential passes a point on a cell membrane. ... The sodium-calcium exchanger (often denoted Na+/Ca2+ exchanger or exchange protein) is an antiporter ion pump membrane protein which removes calcium from cells. ... oommen sir is a fool. ... Ion channels are pore-forming proteins that help to establish and control the small voltage gradient that exists across the plasma membrane of all living cells (see cell potential) by allowing the flow of ions down their electrochemical gradient. ... In cell biology, cAMP-dependent protein kinase (cAPK), also known as protein kinase A (PKA)(EC 2. ... A photoreceptor, or photoreceptor cell, is a specialized type of neuron found in the eyes retina that is capable of phototransduction. ... Cyclic guanosine monophosphate (cGMP) is a second messenger derived from GTP. Cyclic guanosine monophosphate (cGMP) is a cyclic nucleotide derived from guanosine triphosphate (GTP). ... simply; your nose receives messages from the environment sending them to the olfactory centre which is present in the cerebrum the largest part of brain: then you either smell a good smell or a bad smell stink with parts of seconds. ...

Averaged activity of the receptor neuron to an odor can be measured by an electroolfactogram in vertebrates or an electroantenogram in insects. Electroantennogram or EAG is a technique by which we measure the average output of the antenna to the brain for a given odor. ...

In the brain

Olfactory sensory neurons project axons to the brain within the olfactory nerve, (cranial nerve I). These axons pass to the olfactory bulb through the cribriform plate, which in-turn projects olfactory information to the olfactory cortex and other areas. The axons from the olfactory receptors converge in the olfactory bulb within small (~50 micrometers in diameter) structures called glomeruli. Mitral cells in the olfactory bulb form synapses with the axons within glomeruli and send the information about the odor to multiple other parts of the olfactory system in the brain where multiple signals may be processed to form a synthesized olfactory perception. There is a large degree of convergence here, with twenty-five thousand axons synapsing on one hundred or so mitral cells, and with each of these mitral cells projecting to multiple glomeruli. Mitral cells also project to periglomerular cells and granular cells that inhibit the mitral cells surrounding it (lateral inhibition). Granular cells also mediate inhibition and excitation of mitral cells through pathways from centrifugal fibres and the anterior olfactory nuclei. An axon or nerve fiber, is a long, slender projection of a nerve cell, or neuron, that conducts electrical impulses away from the neurons cell body or soma. ... The olfactory nerve is the first of twelve cranial nerves. ... Cranial nerves are nerves which start directly from the brainstem instead of the spinal cord. ... The olfactory bulb is a structure of the vertebrate forebrain involved in olfaction, the perception of odors. ... The cribriform plate of the ethmoid bone (horizontal lamina) [Fig. ... The olfactory system is the sensory system used for olfaction. ... Olfactory receptors are a type of G protein-coupled receptor in olfactory receptor neurons. ... The olfactory bulb is a structure of the vertebrate forebrain involved in olfaction, the perception of odors. ... Glomerulus refers to two unrelated structures in the body, both named for their globular form. ... Mitral cells are neurons that make up a part of the olfactory system. ... Odor receptors on the antennae of a Luna moth An odor or odour (see spelling differences) is a chemical dissolved in air, generally at a very low concentration, which we perceive by the sense of olfaction. ... Drawing of Purkinje cells (A) and granule cells (B) from pigeon cerebellum by Santiago RamÃ³n y Cajal, 1899. ... simply; your nose receives messages from the environment sending them to the olfactory centre which is present in the cerebrum the largest part of brain: then you either smell a good smell or a bad smell stink with parts of seconds. ...

The mitral cells leave the olfactory bulb in the lateral olfactory tract, which synapses on five major regions of the olfactory cortex: the anterior olfactory nucleus, the olfactory tubercle, the orbitofrontal cortex, the pyriform cortex and the enterorhinal cortex. The anterior olfactory nucleus projects, via the anterior comissure, to the contralateral olfactory bulb, inhibiting it. The olfactory tubercle projects to the medial dorsal nucleus of the thalamus, which then projects to the orbitofrontal cortex. The orbitofrontal cortex mediates conscious perception of the odour. The 3-layered pyriform cortex projects to a number of thalamic and hypothalamic nuclei, the hippocampus and amygdala and the orbitofrontal cortex but its function is largely unknown. The enterorhinal cortex projects to the amygdala and is involved in emotional and autonomic responses to odour. It also projects to the hippocampus and is involved in motivation and memory. Odour information is easily stored in long term memory and has strong connections to emotional memory. This is possibly due to the olfactory system's close anatomical ties to the limbic system and hippocampus, areas of the brain that have long been known to be involved in emotion and place memory, respectively. The anterior olfactory nucleus is a cranial nucleus for the olfactory nerve. ... The orbitofrontal cortex (OFC) is a region of association cortex of the human brain involved in cognitive processes such as decision making. ... The Anterior Commissure (precommissure) is a bundle of white fibers, connecting the two cerebral hemispheres across the middle line, and placed in front of the columns of the fornix. ... The medial dorsal nucleus is a a large nucleus in the thalamus. ... This article or section does not cite its references or sources. ... Long-term memory (LTM) is memory that lasts from days to years. ... Emotional memory is an element of the Stanislavski System, an approach to acting. ... The limbic system within the brain. ... The hippocampus is located in the medial temporal lobe of the brain. ...

Since any one receptor is responsive to various odorants, and there is a great deal of convergence at the level of the olfactory bulb, it seems strange that we are able to distinguish so many different odours. There must be a highly complex form of processing occurring, however, as it can be shown that whilst many neurons in the olfactory bulb (and even the pyriform cortex and amygdala) are responsive to many different odours, half the neurons in the orbitofrontal cortex are responsive only to one odour and the rest to only a few. It has been shown through microelectrode studies that each individual odour gives a particular specific spatial map of excitation in the olfactory bulb. It is possible that through spatial encoding, the brain is able to distinguish specific odours. However, temporal coding must be taken into account. Over time, the spatial maps change, even for one particular odour, and the brain must be able to process these details as well.

In insects smells are sensed by sensilla located on the antenna and first processed by the antennal lobe (analogous to the olfactory bulb), and next by the mushroom bodies. Orders See taxonomy Insects (Class Insecta) are a major group of arthropods and the most diverse group of animals on the Earth, with over a million described species â€” more than all other animal groups combined [1]. Insects may be found in nearly all environments on the planet, although only a... Antennal Lobe is the deutocerebral neuropil of the insect which receive the input from the sensory neurons on the antenna. ... The olfactory bulb is a structure of the vertebrate forebrain involved in olfaction, the perception of odors. ...

Pheromonal olfaction

Some pheromones are detected by the olfactory system, although in many vertebrates pheromones are also detected by the vomeronasal organ, located in the vomer, between the nose and the mouth. Snakes use it to smell prey, sticking their tongue out and touching it to the organ. Some mammals make a face called flehmen to direct air to this organ. Fanning honeybee exposes Nasonov gland (white-at tip of abdomen) releasing pheromone to entice swarm into an empty hive A pheromone is any chemical or set of chemicals produced by a living organism that transmits a message to other members of the same species. ... The vomeronasal organ (VNO) or Jacobsons organ is an auxiliary olfactory sense organ in some tetrapods. ... The Flehmen response is a particular type of curling of the lips in ungulates, felids, and many other mammals, which facilitates the transfer of chemicals into the vomeronasal organ. ...

In women, the sense of olfaction is strongest around the time of ovulation, significantly stronger than during other phases of the menstrual cycle and also stronger than the sense in males.^[5] Ovulation is the process in the menstrual cycle by which a mature ovarian follicle ruptures and discharges an ovum (also known as an oocyte, female gamete, or casually, an egg) that participates in reproduction. ... Menstrual cycle The menstrual cycle is a recurring cycle of physiological changes in the females of some animal species that is associated with reproductive fertility. ...

The MHC genes (known as HLA in humans) are a group of genes present in many animals and important for the immune system; in general offspring from parents with differing MHC genes have a stronger immune system. Fish, mice and female humans are able to smell some aspect of the MHC genes of potential sex partners and prefer partners with MHC genes different from their own.^[6]^[7] MHC I (1hsa) vs MHC II (1dlh) (more details. ... The human leukocyte antigen system (sometimes human lymphocyte antigen) (HLA) is the general name of a group of genes in the human major histocompatibility complex (MHC) region on human chromosome 6 (mouse chromosome 17) that encodes the cell-surface antigen-presenting proteins. ... A scanning electron microscope image of a single lymphocyte, a component of the human immune system A poop system is a collection of mechanisms within an organism that protect against infection by identifying and killing pathogens. ...

Olfaction and taste

Olfaction, taste and trigeminal receptors together contribute to flavor. The human tongue can only distinguish among seven to eight distinct types of taste, while the nose can distinguish among hundreds of substances, even in minute quantities. Olfaction amplifies the sense of taste, as can be proven by a simple "kitchen" experiment. If peeled pieces of apple are placed in one bowl, and peeled pieces of potato in another, and then the nostrils are held completely closed while a piece from one bowl is sampled, the taste of apple and potato are indistinguishable. Taste is one of the traditional five senses and refers to the ability to detect of flavor of foodstuffs and other substances (e. ... The trigeminal nerve is the fifth (V) cranial nerve, and carries sensory information from most of the face, as well as motor supply to the muscles of mastication (the muscles enabling chewing), tensor tympani (in the middle ear), and other muscles in the floor of the mouth, such as the... Flavor or flavour (see spelling differences) is the sensory impression of a food or other substance, and is determined mainly by the chemical senses of taste and smell. ... For other uses, see Tongue (disambiguation). ... Taste is one of the traditional five senses and refers to the ability to detect of flavor of foodstuffs and other substances (e. ...

Disorders of olfaction

Anosmia is the lack of olfactory, or a loss of the ability to smell. ... Hyposmia is a reduced ability to smell and to detect odors. ... Phantosmia is the phenomenon of smelling odors that arent really present. ...

Quantifying olfaction

Scientists have devised methods for quantifying the intensity of odors, particularly for the purpose of analyzing unpleasant or objectionable odors released by an industrial source into a community. Since the 1800s industrial countries have encountered incidents where proximity of an industrial source or landfill produced adverse reactions to nearby residents regarding airborne odor. The basic theory of odor analysis is to measure what extent of dilution with "pure" air is required before the sample in question is rendered indistinguishable from the "pure" or reference standard. Since each person perceives odor differently, an "odor panel" composed of several different people is assembled, each sniffing the same sample of diluted specimen air.

Many air management districts in the USA have numerical standards of acceptability for the intensity of odor that is allowed to cross into a residential property. For example the Bay Area Air Quality Management District has applied its standard in regulating numerous industries, landfills and sewage treatment plants. Example applications this district has engaged are the San Mateo, California wastewater treatment plant; the Bill Graham ampitheatre, Mountain View, California; and the IT Corporation waste ponds, Martinez, California.-1... Hillsdale Inn, Honeymoon Suite (demolished 5 April 2001) San Mateo is a city in San Mateo County, California, USA. It is one of the larger suburbs on the San Francisco Peninsula, located between Burlingame to the north, Foster City to the East, and Belmont to the south. ... Mountain View is a city in Santa Clara County, in the U.S. state of California. ... IT Corporation is an United States industrial company whose principal business is the disposal of industrial hazardous waste. ... Martinez Court House, California Martinez is the county seat of Contra Costa County, California. ...

Olfaction in other animals

The importance and sensitivity of smell varies among different organisms; most mammals have a good sense of smell, whereas most birds do not, excepting the tubenoses (e.g., petrels and albatrosses) and the kiwis. Among mammals it is well developed in the carnivores and ungulates, who must always be aware of each other, and in those, such as the moles, who smell for their food. Subclasses Allotheria* Order Multituberculata (extinct) Order Volaticotheria (extinct) Order Palaeoryctoides (extinct) Order Triconodonta (extinct) Prototheria Order Monotremata Theria Infraclass Marsupialia Infraclass Eutheria The mammals are the class of vertebrate animals characterized by the production of milk in females for the nourishment of young, from mammary glands present on most species... Aves redirects here. ... Procellariiformes (from the Latin procella, a storm) is an order of birds formerly called Tubinares and still called tubenoses in English. ... The petrels are seabirds in the bird order Procellariiformes. ... Genera Diomedea Thalassarche Phoebastria Phoebetria Albatrosses, of the biological family Diomedeidae, are large seabirds allied to the procellariids, storm-petrels and diving-petrels in the order Procellariiformes (the tubenoses). ... Species See text. ... This tigers sharp teeth and strong jaws are the classical physical traits expected from carnivorous mammalian predators A carnivore (IPA: ), meaning meat eater (Latin carne meaning flesh and vorare meaning to devour), is an animal that eats a diet consisting mainly of meat, whether it comes from live animals... Llamas such as this, which have two toes, are artiodactylas -- even toed ungulates Ungulates (meaning roughly hoofed or hoofed animal) make up several orders of mammals, of which six to eight survive. ... Genera 17 genera, see text Moles are members of the family (Talpidae) of mammals in the order Soricomorpha that live underground, burrowing holes. ...

Dogs in general have a nose approximately a hundred thousand to a million times more sensitive than a human's. Scenthounds as a group can smell one to ten million times more acutely than a human, and Bloodhounds, who have the keenest sense of smell of any dogs, have noses ten to a hundred million times more sensitive than a human's. They were bred for the specific purpose of tracking humans, and can detect a scent trail a few days old. The second most sensitive nose is possessed by the Basset Hound, which was bred to track and hunt rabbits and other small animals. Like most scent hounds, the Basset Hound has long ears, large nasal passages, and a sturdy body for endurance. ... A Bloodhound (also known as the St. ... The Basset Hound is a short-legged breed of dog of the hound family. ...

The sense of smell is less developed in the catarrhine primates (Catarrhini), and nonexistent in cetaceans, which compensate with a well-developed sense of taste. In some prosimians, such as the Red-bellied Lemur, scent glands occur atop the head. In many species, olfaction is highly tuned to pheromones; a male silkworm moth, for example, can sense a single molecule of bombykol. Families 15, See classification A primate (L. prima, first) is any member of the biological order Primates, the group that contains all the species commonly related to the lemurs, monkeys, and apes, with the latter category including humans. ... Families Cercopithecidae Hylobatidae Hominidae Catarrhini is the unranked group of the Primates, one of the three major divisions of the suborder Haplorrhini. ... Suborders Mysticeti Odontoceti Archaeoceti (extinct) (see text for families) The order Cetacea includes whales, dolphins and porpoises. ... Taste is one of the traditional five senses and refers to the ability to detect of flavor of foodstuffs and other substances (e. ... Prosimians are the most primitive extant primates; they represent forms that were ancestral to monkeys, apes and humans. ... Binomial name Eulemur rubriventer (I. Geoffroy, 1850) The Red-bellied Lemur (Lemur rubriventer) is a medium sized prosimian with a luxuriant chestnut brown coat. ... Fanning honeybee exposes Nasonov gland (white-at tip of abdomen) releasing pheromone to entice swarm into an empty hive A pheromone is any chemical or set of chemicals produced by a living organism that transmits a message to other members of the same species. ... Binomial name Bombyx mori Linnaeus, 1758 For other senses of this word, see silkworm (disambiguation). ... Bombykol Many species use pheromone signals to direct essential behaviors such as mating, feeding, combat, flight, and nurturing the young. ...

Insects primarily use their antennae for olfaction. Sensory neurons in the antenna generate odor-specific electrical signals called spikes in response to odour. They process these signals from the sensory neurons in the antennal lobe followed by the mushroom bodies and lateral horn of the brain. The antennae have the sensory neurons in the sensilla and they have their axons terminating in the antennal lobes where they synapse with other neurons there in semidelineated (with membrane boundaries) called glomeruli. These antennal lobes have two kinds of neurons, projection neurons (excitatory) and local neurons (inhibitory). The projection neurons send their axon terminals to mushroom body and lateral horn (both of which are part of the protocerebrum of the insects) and local neurons have no axons. Recordings from projection neurons show in some insects strong specialization and discrimination for the odors presented (especially for the projection neurons of the macroglomeruli, a specialized complex of glomeruli responsible for the pheromones detection). Processing beyond this level is not exactly known though some preliminary results are available. For other uses, see Antenna. ... Antennal Lobe is the deutocerebral neuropil of the insect which receive the input from the sensory neurons on the antenna. ... The mushroom bodies or corpora pedunculata are a pair of structures in the brain of insects and other arthropods. ... In the thoracic region, the postero-lateral part of the anterior column projects lateralward as a triangular field, which is named the lateral column (lateral cornu, lateral horn). ... An axon, or nerve fiber, is a long slender projection of a nerve cell, or neuron, which conducts electrical impulses away from the neurons cell body or soma. ...

References

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