The olfactory system is the sensory system used for olfaction. See also Sense A sensory system is a part of the Nervous system responsible for processing sensory information Olfaction (also known as olfactics or smell) refers to the Sense of smell. Most mammals and reptiles have two distinct parts to their olfactory system: a main olfactory system and an accessory olfactory system. The Accessory olfactory system (AOS is one of the two Olfactory systems commonly found in Vertebrates. The main olfactory system detects volatile, airborn substances, while the accessory olfactory system senses fluid-phase stimuli. Behavioral evidence indicates that most often, the stimuli detected by the accessory olfactory system are pheromones. A pheromone (from Greek φέρω phero "to bear" + ‘ορμόνη " Hormone " is a Chemical that triggers a natural
The olfactory system is often spoken of along with the gustatory system as the chemosensory senses because both transduce chemical signals into perception. The gustatory system is the Sensory system for the sense of Taste. In Physiology, transduction is the conversion of a stimulus from one form to another In Psychology and the Cognitive sciences perception is the process of attaining awareness or understanding of sensory Information.
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Function
The mechanism of the olfactory system can be divided into a peripheral one, sensing an external stimulus and encoding it as an electric signal in neurons, and a central one, where all signals are integrated and processed in the central nervous system. Human beings, humans or man (Origin 1590–1600 L homō man OL hemō the earthly one (see Humus The olfactory bulb is a structure of the Vertebrate Forebrain involved in Olfaction, the perception of Odors. Neurons (ˈnjuːɹɒn also known as neurones and nerve cells) are responsive cells in the Nervous system that process and transmit information In Vertebrates the central nervous system ( CNS) is the part of the Nervous system which is enclosed in the Meninges.
Peripheral
In mammals, the main olfactory system detects odorants that are inhaled through the nose, where they contact the main olfactory epithelium, which contains various olfactory receptors. The olfactory bulb is a structure of the Vertebrate Forebrain involved in Olfaction, the perception of Odors. Mitral cells are Neurons that are part of the Olfactory system. In biology and medicine epithelium is a tissue composed of cells that line the cavities and surfaces of structures throughout the body The glomerulus (plural glomeruli) in Olfaction is a structure in the Olfactory bulb. Olfactory receptors expressed in the Cell membranes of Olfactory receptor neurons are responsible for the detection of Odor molecules Anatomically a nose is a protuberance in Vertebrates that houses the Nostrils or nares which admit and expel air for respiration in conjunction with the The olfactory epithelium is a specialized epithelial tissue inside the Nasal cavity that is involved in smell. Olfactory receptors expressed in the Cell membranes of Olfactory receptor neurons are responsible for the detection of Odor molecules These can distinguish a new odor from the background environmental odors and determine the concentration of the odor.
These olfactory receptors are connected to olfactory receptor neurons in the olfactory epithelium, which transduce receptoractivation into electrical signals in neurons. An olfactory receptor neuron also called an olfactory sensory neuron is the primary transduction cell in the Olfactory system. Neurons (ˈnjuːɹɒn also known as neurones and nerve cells) are responsive cells in the Nervous system that process and transmit information The signals travel along the olfactory nerve, which belongs to the peripheral nervous system. The olfactory nerve, or cranial nerve I, is the first of twelve Cranial nerves The specialized Olfactory receptor neurons of the olfactory nerve are located The peripheral nervous system ( PNS) resides or extends outside the Central nervous system (CNS which consists of the Brain and Spinal cord. This nerve terminates in the olfactory bulb, which belongs to the central nervous system. The olfactory bulb is a structure of the Vertebrate Forebrain involved in Olfaction, the perception of Odors. In Vertebrates the central nervous system ( CNS) is the part of the Nervous system which is enclosed in the Meninges.
Central
Axons from the olfactory sensory neurons converge in the olfactory bulb to form tangles called glomeruli (singular glomerulus). An axon or nerve fiber is a long slender projectionof a nerve cell or Neuron, that conducts electrical impulses away from the neuron's Cell The glomerulus (plural glomeruli) in Olfaction is a structure in the Olfactory bulb. Inside the glomulerus, the axons contact the dendrites of mitral cells and several other types of cells. Dendrites (from Greek δένδρον déndron, “tree” are the branched projections of a Neuron that act to conduct the electrochemical Mitral cells are Neurons that are part of the Olfactory system. Mitral cells send their axons to a number of brain areas, including the piriform cortex, the medial amygdala, and the entorhinal cortex. In Anatomy of Animals the piriform cortex, or pyriform cortex is a region in the Brain. The la amygdalae ( Latin, also la corpus amygdaloideum, singular la amygdala, from Greek el αμυγδαλή grc-Latn amygdalē, 'almond' The entorhinal cortex (EC is an important Memory center in the Brain.
The piriform cortex is probably the area most closely associated with identifying the odor. The medial amygdala is involved in social functions such as mating and the recognition of animals of the same species. The la amygdalae ( Latin, also la corpus amygdaloideum, singular la amygdala, from Greek el αμυγδαλή grc-Latn amygdalē, 'almond' The entorhinal cortex is associated with memory, e. The entorhinal cortex (EC is an important Memory center in the Brain. g. to pair odors with proper memories. The exact functions of these higher areas are a matter of scientific research and debate.
In the central nervous system, odors are represented as patterns of neural activity. These representations may be encoded by space (a pattern of activated neurons across a given olfactory region corresponds to the odor), time (a pattern of action potentials by multiple neurons corresponds to the odor) or a combination of the two. Neurons (ˈnjuːɹɒn also known as neurones and nerve cells) are responsive cells in the Nervous system that process and transmit information In Neurophysiology, the action potential is a self-regenerating Wave of Electrochemical activity that allows Nerve cells to carry a signal Scientists debate whether the odor code is primarially temporal or spatial.
Clinical implications
Damage to the olfactory system can occur by traumatic brain injury, cancer, inhalation of toxic fumes, or neurodegenerative diseases such as Parkinson's disease and Alzheimer's disease. Brain damage, or Acquired brain injury, is the destruction or degeneration of Brain cells. Cancer (medical term Malignant Neoplasm) is a class of Diseases in which a group of cells display uncontrolled Parkinson's disease (also known as Parkinson disease or PD) is a degenerative disorder of the Central nervous system that often impairs the sufferer's Alzheimer's disease ( AD) also called Alzheimer disease or simply Alzheimer's, is the most common form of Dementia. These conditions can cause anosmia. Anosmia is the lack of Olfaction, or an absence of the ability to smell Doctors can detect damage to the olfactory system by presenting the patient with odors via a scratch and sniff card or by having the patient close their eyes and try to identify commonly available odors like coffee or peppermint candy.
History
Linda B. Buck and Richard Axel won the 2004 Nobel Prize in Physiology or Medicine for their work on the olfactory system. Linda B Buck, PhD, (born January 29, 1947) is an American Biologist best known for her work on the Olfactory system Richard Axel (born July 2, 1946, New York City) is an American Neuroscientist whose work on the Olfactory system won him "MMIV" redirects here For the Modest Mouse album see " Baron von Bullshit Rides Again " The Nobel Prize in Physiology or Medicine (Nobelpriset i fysiologi eller medicin is awarded once a year by the Swedish Karolinska Institute.
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