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Olfactory System
The olfactory system, or sense of smell, is the sensory system used for smelling (olfaction). Olfaction is one of the special senses, that have directly associated specific organs. Most mammals and reptiles have a main olfactory system and an accessory olfactory system. The main olfactory system detects airborne substances, while the accessory system senses fluid-phase stimuli. The senses of smell and taste (gustatory system) are often referred to together as the chemosensory system, because they both give the brain information about the chemical composition of objects through a process called transduction. Structure Peripheral The peripheral olfactory system consists mainly of the nostrils, ethmoid bone, nasal cavity, and the olfactory epithelium (layers of thin tissue covered in mucus that line the nasal cavity). The primary components of the layers of epithelial tissue are the mucous membranes, olfactory glands, olfactory neurons, and nerve fibers of the olfactory nerves. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Olfactory Receptor
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 Rat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Olfactory Receptor Neurons
An olfactory receptor neuron (ORN), also called an olfactory sensory neuron (OSN), is a sensory neuron within the olfactory system. Structure Humans have between 10 and 20 million olfactory receptor neurons (ORNs). In vertebrates, ORNs are bipolar neurons with dendrites facing the external surface of the cribriform plate with axons that pass through the cribriform foramina with terminal end at olfactory bulbs. The ORNs are located in the olfactory epithelium in the nasal cavity. The cell bodies of the ORNs are distributed among all three of the stratified layers of the olfactory epithelium. Many tiny hair-like non-motile cilia protrude from the olfactory receptor cell's dendrites. The dendrites extend to the olfactory epithelial surface and each ends in a dendritic knob from which around 20 to 35 cilia protrude. The cilia have a length of up to 100 micrometres and with the cilia from other dendrites form a meshwork in the olfactory mucus. The surface of the cilia is cove ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Olfactory Receptor Neurons
An olfactory receptor neuron (ORN), also called an olfactory sensory neuron (OSN), is a sensory neuron within the olfactory system. Structure Humans have between 10 and 20 million olfactory receptor neurons (ORNs). In vertebrates, ORNs are bipolar neurons with dendrites facing the external surface of the cribriform plate with axons that pass through the cribriform foramina with terminal end at olfactory bulbs. The ORNs are located in the olfactory epithelium in the nasal cavity. The cell bodies of the ORNs are distributed among all three of the stratified layers of the olfactory epithelium. Many tiny hair-like non-motile cilia protrude from the olfactory receptor cell's dendrites. The dendrites extend to the olfactory epithelial surface and each ends in a dendritic knob from which around 20 to 35 cilia protrude. The cilia have a length of up to 100 micrometres and with the cilia from other dendrites form a meshwork in the olfactory mucus. The surface of the cilia is cove ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Afferent Nerve Fiber
Afferent nerve fibers are the axons (nerve fibers) carried by a sensory nerve that relay sensory information from sensory receptors to regions of the brain. Afferent projections ''arrive'' at a particular brain region. Efferent nerve fibers are carried by efferent nerves and ''exit'' a region to act on muscles and glands. In the peripheral nervous system afferent and efferent nerve fibers are part of the somatic nervous system and arise from outside of the spinal cord. Sensory nerves carry the afferent fibers to enter into the spinal cord, and motor nerves carry the efferent fibers out of the spinal cord to act on skeletal muscles. In the central nervous system non-motor efferents are carried in efferent nerves to act on glands. Structure Afferent neurons are pseudounipolar neurons that have a single process leaving the cell body dividing into two branches: the long one towards the sensory organ, and the short one toward the central nervous system (e.g. spinal cord). The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Limbic System
The limbic system, also known as the paleomammalian cortex, is a set of brain structures located on both sides of the thalamus, immediately beneath the medial temporal lobe of the cerebrum primarily in the forebrain.Schacter, Daniel L. 2012. ''Psychology''.sec. 3.20 It supports a variety of functions including emotion, behavior, long-term memory, and olfaction. Emotional life is largely housed in the limbic system, and it critically aids the formation of memories. With a primordial structure, the limbic system is involved in lower order emotional processing of input from sensory systems and consists of the amygdaloid nuclear complex (amygdala), mammillary bodies, stria medullaris, central gray and dorsal and ventral nuclei of Gudden. This processed information is often relayed to a collection of structures from the telencephalon, diencephalon, and mesencephalon, including the prefrontal cortex, cingulate gyrus, limbic thalamus, hippocampus including the parahippocampal gyrus an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cribriform Plate
In mammalian anatomy, the cribriform plate (Latin for lit. ''sieve-shaped''), horizontal lamina or lamina cribrosa is part of the ethmoid bone. It is received into the ethmoidal notch of the frontal bone and roofs in the nasal cavities. It supports the olfactory bulb, and is perforated by olfactory foramina for the passage of the olfactory nerves to the roof of the nasal cavity to convey smell to the brain. The foramina at the medial part of the groove allow the passage of the nerves to the upper part of the nasal septum while the foramina at the lateral part transmit the nerves to the superior nasal concha. A fractured cribriform plate can result in olfactory dysfunction, septal hematoma, cerebrospinal fluid rhinorrhoea (CSF rhinorrhoea), and possibly infection which can lead to meningitis. CSF rhinorrhoea (clear fluid leaking from the nose) is very serious and considered a medical emergency. Aging can cause the openings in the cribriform plate to close, pinching olfactor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Olfactory Nerve Fibers
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 of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sensory Neuron
Sensory neurons, also known as afferent neurons, are neurons in the nervous system, that convert a specific type of stimulus, via their receptors, into action potentials or graded potentials. This process is called sensory transduction. The cell bodies of the sensory neurons are located in the dorsal ganglia of the spinal cord. The sensory information travels on the afferent nerve fibers in a sensory nerve, to the brain via the spinal cord. The stimulus can come from ''exteroreceptors'' outside the body, for example those that detect light and sound, or from ''interoreceptors'' inside the body, for example those that are responsive to blood pressure or the sense of body position. Types and function Different types of sensory neurons have different sensory receptors that respond to different kinds of stimuli. There are at least six external and two internal sensory receptors: External receptors External receptors that respond to stimuli from outside the body are called ex ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cilia
The cilium, plural cilia (), is a membrane-bound organelle found on most types of eukaryotic cell, and certain microorganisms known as ciliates. Cilia are absent in bacteria and archaea. The cilium has the shape of a slender threadlike projection that extends from the surface of the much larger cell body. Eukaryotic flagella found on sperm cells and many protozoans have a similar structure to motile cilia that enables swimming through liquids; they are longer than cilia and have a different undulating motion. There are two major classes of cilia: ''motile'' and ''non-motile'' cilia, each with a subtype, giving four types in all. A cell will typically have one primary cilium or many motile cilia. The structure of the cilium core called the axoneme determines the cilium class. Most motile cilia have a central pair of single microtubules surrounded by nine pairs of double microtubules called a 9+2 axoneme. Most non-motile cilia have a 9+0 axoneme that lacks the central pair of mi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Medical Daily
IBT Media is an American global digital news organization with over 90 million monthly readers, owned by followers of religious leader David Jang. It publishes the ''International Business Times'' and ''Medical Daily'', among others. IBT Media is headquartered in New York City, in the Hanover Square neighborhood of Lower Manhattan. As of 2014, the company posted revenue of about $21 million and generated a profit of about $500,000. Overview Founded as IBT Media in 2006, the company has several brands that it has built organically through specialty vertical sites and also international editions. IBT Media focuses on online publication. Corporate structure and revenue IBT Media is a privately held company, formerly owned by Etienne Uzac and Johnathan Davis. The company has not received outside funding, and has grown with a focus on being an "efficient company", concentrating on the "revenue side as well as on the expenses". It started in 2006, with personal savings, an SBA bank ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sensory Transduction
In physiology, transduction is the translation of arriving stimulus into an action potential by a sensory receptor. It begins when stimulus changes the membrane potential of a receptor cell. A receptor cell converts the energy in a stimulus into an electrical signal. Receptors are broadly split into two main categories: exteroceptors, which receive external sensory stimuli, and interoceptors, which receive internal sensory stimuli. Transduction and the senses The visual system In the visual system, sensory cells called rod and cone cells in the retina convert the physical energy of light signals into electrical impulses that travel to the brain. The light causes a conformational change in a protein called rhodopsin. This conformational change sets in motion a series of molecular events that result in a reduction of the electrochemical gradient of the photoreceptor. The decrease in the electrochemical gradient causes a reduction in the electrical signals going to the brain. Thus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Action Potential Propagation Animation
Action may refer to: * Action (narrative), a literary mode * Action fiction, a type of genre fiction * Action game, a genre of video game Film * Action film, a genre of film * ''Action'' (1921 film), a film by John Ford * ''Action'' (1980 film), a film by Tinto Brass * ''Action 3D'', a 2013 Telugu language film * ''Action'' (2019 film), a Kollywood film. Music * Action (music), a characteristic of a stringed instrument * Action (piano), the mechanism which drops the hammer on the string when a key is pressed * The Action, a 1960s band Albums * ''Action'' (B'z album) (2007) * ''Action!'' (Desmond Dekker album) (1968) * ''Action Action Action'' or ''Action'', a 1965 album by Jackie McLean * ''Action!'' (Oh My God album) (2002) * ''Action'' (Oscar Peterson album) (1968) * ''Action'' (Punchline album) (2004) * ''Action'' (Question Mark & the Mysterians album) (1967) * ''Action'' (Uppermost album) (2011) * ''Action'' (EP), a 2012 EP by NU'EST * ''Action'', a 1984 albu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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