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47-510: [REDACTED] Look up receptor in Wiktionary, the free dictionary. Receptor may refer to: Sensory receptor , in physiology , any neurite structure that, on receiving environmental stimuli , produces an informative nerve impulse Receptor (biochemistry) , in biochemistry, a protein molecule that receives and responds to a neurotransmitter, or other substance Cell surface receptor ,

94-404: A cat uses its inner ear and tail to walk on a thin fence . Equilibrioception in many marine animals is done with an entirely different organ, the statocyst , which detects the position of tiny calcareous stones to determine which way is "up". Plants could be said to exhibit a form of equilibrioception, in that when rotated from their normal attitude the stems grow in the direction that

141-484: A merry-go-round . Blows can also affect equilibrioreception, especially those to the side of the head or directly to the ear. Most astronauts find that their sense of balance is impaired when in orbit because they are in a constant state of weightlessness . This causes a form of motion sickness called space adaptation syndrome . This overview also explains acceleration as its processes are interconnected with balance. There are five sensory organs innervated by

188-538: A chili pepper (due to its main ingredient, capsaicin), the cold sensation experienced after ingesting a chemical such as menthol or icillin, as well as the common sensation of pain are all a result of neurons with these receptors. Problems with mechanoreceptors lead to disorders such as: Internal receptors that respond to changes inside the body are known as interoceptors . The aortic bodies and carotid bodies contain clusters of glomus cells – peripheral chemoreceptors that detect changes in chemical properties in

235-400: A receptor on the outer surface of a cell membrane, that takes part in communication between the cell and the outside world Nuclear receptor , a receptor found within cells that is responsible for sensing steroid and thyroid hormones and certain other molecules Immune receptor , a receptor that occurs on the surface of immunocytes and binds to antigens Receiver (radio) , a device for

282-424: Is a sensory system disorder in which amputees perceive that their amputated limb still exists and they may still be experiencing pain in it. The mirror box developed by V.S. Ramachandran, has enabled patients with phantom limb syndrome to relieve the perception of paralyzed or painful phantom limbs. It is a simple device which uses a mirror in a box to create an illusion in which the sensory system perceives that it

329-457: Is a warmth-sensitive receptor. Mechanoreceptors are sensory receptors which respond to mechanical forces, such as pressure or distortion . Specialized sensory receptor cells called mechanoreceptors often encapsulate afferent fibers to help tune the afferent fibers to the different types of somatic stimulation. Mechanoreceptors also help lower thresholds for action potential generation in afferent fibers and thus make them more likely to fire in

376-425: Is called the vestibulo-ocular reflex (VOR) . The balance system works with the visual and skeletal systems (the muscles and joints and their sensors) to maintain orientation or balance. Visual signals sent to the brain about the body's position in relation to its surroundings are processed by the brain and compared to information from the vestibular and skeletal systems. In the vestibular system, equilibrioception

423-546: Is determined by the level of a fluid called endolymph in the labyrinth , a complex set of tubing in the inner ear. When the sense of balance is interrupted it causes dizziness , disorientation and nausea . Balance can be upset by Ménière's disease , superior canal dehiscence syndrome , an inner ear infection , by a bad common cold affecting the head or a number of other medical conditions including but not limited to vertigo . It can also be temporarily disturbed by quick or prolonged acceleration , for example, riding on

470-405: Is different from Wikidata All article disambiguation pages All disambiguation pages Sensory receptor The sensory information travels on the afferent nerve fibers in a sensory nerve , to the brain via the spinal cord . Spinal nerves transmit external sensations via sensory nerves to the brain through the spinal cord. The stimulus can come from exteroreceptors outside

517-565: Is seeing two hands instead of one, therefore allowing the sensory system to control the "phantom limb". By doing this, the sensory system can gradually get acclimated to the amputated limb, and thus alleviate this syndrome. Hydrodynamic reception is a form of mechanoreception used in a range of animal species. Sense of balance The sense of balance or equilibrioception is the perception of balance and spatial orientation . It helps prevent humans and nonhuman animals from falling over when standing or moving. Equilibrioception

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564-470: Is the largest center through which balance information passes. It is the area of integration between proprioceptive , and vestibular inputs, to aid in unconscious maintenance of balance and posture. The inferior olivary nucleus aids in complex motor tasks by encoding coordinating timing sensory information; this is decoded and acted upon in the cerebellum . The cerebellar vermis has three main parts. The vestibulocerebellum regulates eye movements by

611-401: Is the result of a number of sensory systems working together; the eyes ( visual system ), the inner ears ( vestibular system ), and the body's sense of where it is in space ( proprioception ) ideally need to be intact. The vestibular system, the region of the inner ear where three semicircular canals converge, works with the visual system to keep objects in focus when the head is moving. This

658-430: The cerebrocerebellum plans, times, and initiates movement after evaluating sensory input from, primarily, motor cortex areas, via pons and cerebellar dentate nucleus . It outputs to the thalamus, motor cortex areas, and red nucleus . The flocculonodular lobe is a cerebellar lobe that helps maintain body equilibrium by modifying muscle tone (the continuous and passive muscle contractions). MVN and IVN are in

705-418: The vestibular nerve ; three semicircular canals ( Horizontal SCC , Superior SCC , Posterior SCC ) and two otolith organs ( saccule and utricle ). Each semicircular canal (SSC) is a thin tube that doubles in thickness briefly at a point called osseous ampullae . At their center-base, each contains an ampullary cupula . The cupula is a gelatin bulb connected to the stereocilia of hair cells, affected by

752-466: The air. The molecules in the air are detected by enlarged cilia and microvilli . These sensory neurons produce action potentials. Their axons form the olfactory nerve , and they synapse directly onto neurons in the cerebral cortex ( olfactory bulb ). They do not use the same route as other sensory systems, bypassing the brain stem and the thalamus. The neurons in the olfactory bulb that receive direct sensory nerve input, have connections to other parts of

799-428: The auditory system leads to disorders such as: Thermoreceptors are sensory receptors, which respond to varying temperatures . While the mechanisms through which these receptors operate is unclear, recent discoveries have shown that mammals have at least two distinct types of thermoreceptors. The bulboid corpuscle , is a cutaneous receptor a cold-sensitive receptor, that detects cold temperatures. The other type

846-536: The blood such as oxygen concentration. These receptors are polymodal responding to a number of different stimuli. Nociceptors respond to potentially damaging stimuli by sending signals to the spinal cord and brain. This process, called nociception , usually causes the perception of pain . They are found in internal organs as well as on the surface of the body to "detect and protect". Nociceptors detect different kinds of noxious stimuli indicating potential for damage, then initiate neural responses to withdraw from

893-578: The body are called exteroreceptors . Exteroreceptors include chemoreceptors such as olfactory receptors ( smell ) and taste receptors , photoreceptors ( vision ), thermoreceptors ( temperature ), nociceptors ( pain ), hair cells ( hearing and balance ), and a number of other different mechanoreceptors for touch and proprioception (stretch, distortion and stress). The sensory neurons involved in smell are called olfactory sensory neurons . These neurons contain receptors , called olfactory receptors , that are activated by odor molecules in

940-520: 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 . Sensory neurons in vertebrates are predominantly pseudounipolar or bipolar , and 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 that respond to stimuli from outside

987-423: The brain of Taub's Silver Spring monkeys , there has been a large amount of research into sensory system plasticity . Huge strides have been made in treating disorders of the sensory system. Techniques such as constraint-induced movement therapy developed by Taub have helped patients with paralyzed limbs regain use of their limbs by forcing the sensory system to grow new neural pathways . Phantom limb syndrome

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1034-448: The brain. The brain then processes these signals and interprets them as specific taste sensations, allowing you to perceive and enjoy the flavors of the foods you consume. When taste receptor cells are stimulated by the binding of these chemical compounds (tastants), it can lead to changes in the flow of ions, such as sodium (Na+), calcium (Ca2+), and potassium (K+), across the cell membrane. In response to tastant binding, ion channels on

1081-407: The cilia are once again stimulated. For example, lying down stimulates cilia and standing up stimulates cilia, however, for the time spent lying the signal that you are lying remains active, even though the membrane resets. Otolithic organs have a thick, heavy gelatin membrane that, due to inertia (like endolymph), lags behind and continues ahead past the macula it overlays, bending and activating

1128-426: The contained cilia. Utricle responds to linear accelerations and head-tilts in the horizontal plane (head to shoulder), whereas saccule responds to linear accelerations and head-tilts in the vertical plane (up and down). Otolithic organs update the brain on the head-location when not moving; SCC update during movement. Kinocilium are the longest stereocilia and are positioned (one per 40-70 regular cilia) at

1175-413: The cupula once again to signal a change in movement. Pilots doing long banked turns begin to feel upright (no longer turning) as endolymph matches canal rotation; once the pilot exits the turn the cupula is once again stimulated, causing the feeling of turning the other way, rather than flying straight and level. The horizontal SCC handles head rotations about a vertical axis (e.g. looking side to side),

1222-472: The end of the bundle. If stereocilia go towards kinocilium, depolarization occurs, causing more neurotransmitters , and more vestibular nerve firings, as compared to when stereocilia tilt away from kinocilium ( hyperpolarization , less neurotransmitter, less firing). First order vestibular nuclei (VN) project to lateral vestibular nucleus (IVN), medial vestibular nucleus (MVN), and superior vestibular nucleus (SVN). The inferior cerebellar peduncle

1269-550: The endolymph bends and activates the cupula. When the cupula bends, the connected stereocilia bend along with it, activating chemical reactions in the hair cells surrounding crista ampullaris and eventually create action potentials carried by the vestibular nerve signaling to the body that it has moved in space. After any extended rotation, the endolymph catches up to the canal and the cupula returns to its upright position and resets. When extended rotation ceases, however, endolymph continues, (due to inertia) which bends and activates

1316-553: The flow of information. It is speculatively able to stop signals, ending transmission of unimportant info. The thalamus relays info between pons (cerebellum link), motor cortices, and insula . The insula is also heavily connected to motor cortices; the insula is likely where balance is likely brought into perception. The oculomotor nuclear complex refers to fibers going to tegmentum (eye movement), red nucleus ( gait (natural limb movement)), substantia nigra (reward), and cerebral peduncle (motor relay). Nucleus of Cajal are one of

1363-554: The globe on the opposite side of the eye (e.g. looking down directs the pupil down and depresses (towards the brain) the top of the globe). The pupil is not only directed, but often rotated, by these muscles. (See visual system ) The thalamus and superior colliculus are connected via the lateral geniculate nucleus . The superior colliculus (SC) is the topographical map for balance and quick orienting movements with primarily visual inputs. SC integrates multiple senses. Some animals have better equilibrioception than humans; for example,

1410-403: The integration of visual info provided by the superior colliculus and balance information. The spinocerebellum integrates visual, auditory, proprioceptive, and balance information to act out body and limb movements. It receives input from the trigeminal nerve , dorsal column (of the spinal cord ), midbrain , thalamus , reticular formation and vestibular nuclei ( medulla ) outputs . Lastly,

1457-438: The intensity of light, allowing for vision in dim lighting. The concentrations and ratio of rods to cones is strongly correlated with whether an animal is diurnal or nocturnal . In humans, rods outnumber cones by approximately 20:1, while in nocturnal animals, such as the tawny owl , the ratio is closer to 1000:1. Retinal ganglion cells are involved in the sympathetic response . Of the ~1.3 million ganglion cells present in

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1504-417: The interactions with other types of neurons in the retina. The five basic classes of neurons within the retina are photoreceptor cells , bipolar cells , ganglion cells , horizontal cells , and amacrine cells . The basic circuitry of the retina incorporates a three-neuron chain consisting of the photoreceptor (either a rod or cone ), bipolar cell, and the ganglion cell. The first action potential occurs in

1551-435: The market that are used to manipulate or treat sensory system disorders. For instance, gabapentin is a drug that is used to treat neuropathic pain by interacting with one of the voltage-dependent calcium channels present on non-receptive neurons. Some drugs may be used to combat other health problems, but can have unintended side effects on the sensory system. Dysfunction in the hair cell mechanotransduction complex, along with

1598-421: The medulla, LVN and SVN are smaller and in pons. SVN, MVN, and IVN ascend within the medial longitudinal fasciculus . LVN descend the spinal cord within the lateral vestibulospinal tract and ends at the sacrum . MVN also descend the spinal cord, within the medial vestibulospinal tract , ending at lumbar 1 . The thalamic reticular nucleus distributes information to various other thalamic nuclei, regulating

1645-559: The movement, the hair cell can either hyperpolarize or depolarize. When the movement is towards the tallest stereocilia , the Na cation channels open allowing Na to flow into cell and the resulting depolarization causes the Ca channels to open, thus releasing its neurotransmitter into the afferent auditory nerve. There are two types of hair cells: inner and outer. The inner hair cells are the sensory receptors . Problems with sensory neurons associated with

1692-409: The named oculomotor nuclei, they are involved in eye movements and reflex gaze coordination. The abducens nerve solely innervates the lateral rectus muscle of the eye, moving the eye with the trochlear nerve . The trochlear solely innervates the superior oblique muscle of the eye. Together, trochlear and abducens contract and relax to simultaneously direct the pupil towards an angle and depress

1739-485: The olfactory system and many parts of the limbic system . 9. Taste sensation is facilitated by specialized sensory neurons located in the taste buds of the tongue and other parts of the mouth and throat. These sensory neurons are responsible for detecting different taste qualities, such as sweet, sour, salty, bitter, and savory. When you eat or drink something, chemicals in the food or liquid interact with receptors on these sensory neurons, triggering signals that are sent to

1786-496: The potential loss of specialized ribbon synapses, can lead to hair cell death, often caused by ototoxic drugs like aminoglycoside antibiotics poisoning the cochlea. Through the use of these toxins, the K+ pumping hair cells cease their function. Thus, the energy generated by the endocochlear potential which drives the auditory signal transduction process is lost, leading to hearing loss. Ever since scientists observed cortical remapping in

1833-453: The presence of sensory stimulation. Some types of mechanoreceptors fire action potentials when their membranes are physically stretched. Proprioceptors are another type of mechanoreceptors which literally means "receptors for self". These receptors provide spatial information about limbs and other body parts. Nociceptors are responsible for processing pain and temperature changes. The burning pain and irritation experienced after eating

1880-479: The reception of electromagnetic signals. Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with the title Receptor . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=Receptor&oldid=1191691516 " Category : Disambiguation pages Hidden categories: Short description

1927-414: The relative movement of the endolymph it is bathed in. Since the cupula is part of the bony labyrinth , it rotates along with actual head movement, and by itself without the endolymph, it cannot be stimulated and therefore, could not detect movement. Endolymph follows the rotation of the canal; however, due to inertia its movement initially lags behind that of the bony labyrinth. The delayed movement of

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1974-405: The retina, 1-2% are believed to be photosensitive. Issues and decay of sensory neurons associated with vision lead to disorders such as: The auditory system is responsible for converting pressure waves generated by vibrating air molecules or sound into signals that can be interpreted by the brain. This mechanoelectrical transduction is mediated with hair cells within the ear. Depending on

2021-451: The retinal ganglion cell. This pathway is the most direct way for transmitting visual information to the brain. There are three primary types of photoreceptors: Cones are photoreceptors that respond significantly to color . In humans the three different types of cones correspond with a primary response to short wavelength (blue), medium wavelength (green), and long wavelength (yellow/red). Rods are photoreceptors that are very sensitive to

2068-455: The sensations in terms of which cells are active. A sensory receptor's adequate stimulus is the stimulus modality for which it possesses the adequate sensory transduction apparatus. Adequate stimulus can be used to classify sensory receptors: Sensory receptors can be classified by location: Somatic sensory receptors near the surface of the skin can usually be divided into two groups based on morphology: There are many drugs currently on

2115-414: The stimulus. Information coming from the sensory neurons in the head enters the central nervous system (CNS) through cranial nerves . Information from the sensory neurons below the head enters the spinal cord and passes towards the brain through the 31 spinal nerves . The sensory information traveling through the spinal cord follows well-defined pathways. The nervous system codes the differences among

2162-403: The superior SCC handles head movement about a lateral axis (e.g. head to shoulder), and the posterior SCC handles head rotation about a rostral-caudal axis (e.g. nodding). SCC sends adaptive signals, unlike the two otolith organs, the saccule and utricle, whose signals do not adapt over time. A shift in the otolithic membrane that stimulates the cilia is considered the state of the body until

2209-484: The taste receptor cell membrane can open or close. This can lead to depolarization of the cell membrane, creating an electrical signal. Similar to olfactory receptors , taste receptors (gustatory receptors) in taste buds interact with chemicals in food to produce an action potential . Photoreceptor cells are capable of phototransduction , a process which converts light ( electromagnetic radiation ) into electrical signals. These signals are refined and controlled by

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