"a protein motor called prestin on their outer membranes; it generates additional movement that couples back to the fluid–membrane wave. This ""active amplifier"" is essential in the ear's ability to amplify weak sounds. The active amplifier also leads to the phenomenon of soundwave vibrations being emitted from the cochlea back into the ear canal through the middle ear (otoacoustic emissions). Otoacoustic emissions are due to a wave exiting the cochlea via the oval window, and propagating back through the middle ear to the eardrum, and out the ear canal, where it can be picked up by a microphone. Otoacoustic emissions"
"stirrups. Ossicles The ossicles (also called auditory ossicles) are three bones in either middle ear that are among the smallest bones in the human body. They serve to transmit sounds from the air to the fluid-filled labyrinth (cochlea). The absence of the auditory ossicles would constitute a moderate-to-severe hearing loss. The term ""ossicle"" literally means ""tiny bone"". Though the term may refer to any small bone throughout the body, it typically refers to the malleus, incus, and stapes (hammer, anvil, and stirrup) of the middle ear. The ossicles are, in order from the eardrum to the inner ear (from superficial"
"Stapes The stapes or stirrup is a bone in the middle ear of humans and other mammals which is involved in the conduction of sound vibrations to the inner ear. The stirrup-shaped small bone is on and transmits these to the oval window, medially. The stapes is the smallest and lightest named bone in the human body, and is so-called because of its resemblance to a stirrup (). The stapes is the third bone of the three ossicles in the middle ear. The stapes is a stirrup-shaped bone, and the smallest in the human body. It rests on the oval"
"stirrup and act to decrease sound before it hits the inner ear. In general, the ossicles act as a barrier to the inner ear for sound energy. Inner ear Inner ear fluid called endolymph receives the sound energy. After receiving the energy, later within the inner ear there are two parts: the cochlea that utilizes sound waves from the ossicles and the vestibular apparatus that manages the rabbit's position in regards to movement. Within the cochlea there is a basilar membrane that contains sensory hair structures utilized to send nerve signals to the brain so it can recognize different sound"
"probably created in mediaeval times from ""to stand"" (), as stirrups did not exist in the early Latin-speaking world. Stapes The stapes or stirrup is a bone in the middle ear of humans and other mammals which is involved in the conduction of sound vibrations to the inner ear. The stirrup-shaped small bone is on and transmits these to the oval window, medially. The stapes is the smallest and lightest named bone in the human body, and is so-called because of its resemblance to a stirrup (). The stapes is the third bone of the three ossicles in the middle"
"end of the cochlea, at an opening known as the helicotrema, the scala vestibuli merges with the scala tympani. The fluid found in these two cochlear chambers is perilymph, while scala media, or the cochlear duct, is filled with endolymph. The auditory hair cells in the cochlea are at the core of the auditory system's special functionality (similar hair cells are located in the semicircular canals). Their primary function is mechanotransduction, or conversion between mechanical and neural signals. The relatively small number of the auditory hair cells is surprising when compared to other sensory cells such as the rods and"
"the cochlear duct. Its fluid, endolymph, also contains electrolytes and proteins, but is chemically quite different from perilymph. Whereas the perilymph is rich in sodium ions, the endolymph is rich in potassium ions, which produces an ionic, electrical potential. The hair cells are arranged in four rows in the organ of Corti along the entire length of the cochlear coil. Three rows consist of outer hair cells (OHCs) and one row consists of inner hair cells (IHCs). The inner hair cells provide the main neural output of the cochlea. The outer hair cells, instead, mainly ""receive"" neural input from the"
"moves out, and this allows movement of the fluid within the cochlea, leading to movement of the cochlear inner hair cells and thus hearing. If the round window were to be absent or rigidly fixed (as can happen in some congenital abnormalities), the stapes footplate would be pushing incompressible fluid against the unyielding walls of the cochlea. It would therefore not move to any useful degree leading to a hearing loss of about 60dB. This is, unsurprisingly, the same as for conditions where the stapes itself is fixed, such as otosclerosis. The round window is located within the mesotympanum, at"
"sends them to receptor cells. The ossicles which are connected to the eardrum pass the vibrations to the fluid-filled cochlea. Once the vibrations reach the cochlea, the stirrup (part of the ossicles) puts pressure on the oval window. This opening allows the vibrations to move through the liquid in the cochlea where the receptive organ is able to sense it. There are many different qualities in sound stimuli including loudness, pitch and timbre. The human ear is able to detect differences in pitch through the movement of auditory hair cells found on the basilar membrane. High frequency sounds will stimulate"
"ear. The inner ear contains the cochlea, the liquid-filled structure containing the hair cells. These cells serve to transform the incoming vibration to electrical signals, which can then be transmitted to the brain. The auditory nerve carries the signal generated by the hair cells away from the inner ear and towards the auditory receiving area in the cortex. The signal then travels through fibers to several subcortical structures and then to the primary auditory receiving area in the temporal lobe Humans use several cues to determine the location of a given stimuli, mainly by using the timing difference between ears."
"duct. All of these structures together constitute the cochlea. In mammals (other than monotremes), the cochlea is extended still further, becoming a coiled structure in order to accommodate its length within the head. The organ of Corti also has a more complex structure in mammals than it does in other amniotes. The arrangement of the inner ear in living amphibians is, in most respects, similar to that of reptiles. However, they often lack a basilar papilla, having instead an entirely separate set of sensory cells at the upper edge of the saccule, referred to as the papilla amphibiorum, which appear"
"length of the cochlea is stiffest nearest its beginning at the oval window, where the stapes introduces the vibrations coming from the eardrum. Since its stiffness is high there, it allows only high-frequency vibrations to move the basilar membrane, and thus the hair cells. The farther a wave travels towards the cochlea's apex (the ""helicotrema""), the less stiff the basilar membrane is; thus lower frequencies travel down the tube, and the less-stiff membrane is moved most easily by them where the reduced stiffness allows: that is, as the basilar membrane gets less and less stiff, waves slow down and it"
"Coelom The coelom is the main body cavity in most animals and is positioned inside the body to surround and contain the digestive tract and other organs. In developed animals, it is lined with mesothelium. In other animals, such as molluscs, it remains undifferentiated. The term ""coelom"" derives from the Ancient Greek word (), meaning ""cavity"". During the development of the embryo, coelom formation begins in the gastrulation stage. The developing digestive tube of an embryo forms as a blind pouch called the archenteron. In Protostomes, the coelom forms by a process known as schizocoely. The archenteron initially forms, and"
"its precise incidence cannot be determined. Birds have an auditory system similar to that of mammals, including a cochlea. Reptiles, amphibians, and fish do not have cochleas but hear with simpler auditory organs or vestibular organs, which generally detect lower-frequency sounds than the cochlea. In reptiles, sound is transmitted to the inner ear by the stapes (stirrup) bone of the middle ear. This is pressed against the oval window, a membrane-covered opening on the surface of the vestibule. From here, sound waves are conducted through a short perilymphatic duct to a second opening, the round window, which equalizes pressure, allowing"
"cases the sclerites are fused to various degrees. Thorax The thorax or chest (from the Greek θώραξ ""thorax"" ""breastplate, cuirass, corslet"" via ) is a part of the anatomy of humans and various other animals located between the neck and the abdomen. The thorax includes the thoracic cavity and the thoracic wall. It contains organs including the heart, lungs, and thymus gland, as well as muscles and various other internal structures. Many diseases may affect the chest, and one of the most common symptoms is chest pain. In humans and other hominids, the thorax is the chest region of the"
"Trapezoid body The trapezoid body (the ventral acoustic stria) is part of the auditory pathway where some of the axons coming from the cochlear nucleus (specifically, the anterior cochlear nucleus) decussate (cross over) to the other side before traveling on to the superior olivary nucleus. This is believed to help with localization of sound. The trapezoid body is located in the caudal pons, or more specifically the pontine tegmentum. It is situated between the pontine nucleus and the medial lemniscus. After nerves from the cochlear nucleus cross over in the trapezoid body and go on to the superior olivary nucleus,"
"Choroid The choroid, also known as the choroidea or choroid coat, is the vascular layer of the eye, containing connective tissues, and lying between the retina and the sclera. The human choroid is thickest at the far extreme rear of the eye (at 0.2 mm), while in the outlying areas it narrows to 0.1 mm. The choroid provides oxygen and nourishment to the outer layers of the retina. Along with the ciliary body and iris, the choroid forms the uveal tract. The structure of the choroid is generally divided into four layers (classified in order of furthest away from the"
"Ossicles The ossicles (also called auditory ossicles) are three bones in either middle ear that are among the smallest bones in the human body. They serve to transmit sounds from the air to the fluid-filled labyrinth (cochlea). The absence of the auditory ossicles would constitute a moderate-to-severe hearing loss. The term ""ossicle"" literally means ""tiny bone"". Though the term may refer to any small bone throughout the body, it typically refers to the malleus, incus, and stapes (hammer, anvil, and stirrup) of the middle ear. The ossicles are, in order from the eardrum to the inner ear (from superficial to"
"Cochlin Cochlin is a protein that in humans is encoded by the ""COCH"" gene. The protein encoded by this gene is highly conserved in human, mouse, and chicken, showing 94% and 79% amino acid identity of human to mouse and chicken sequences, respectively. Hybridization to this gene was detected in spindle-shaped cells located along nerve fibers between the auditory ganglion and sensory epithelium. These cells accompany neurites at the habenula perforata, the opening through which neurites extend to innervate hair cells. This and the pattern of expression of this gene in chicken inner ear paralleled the histologic findings of acidophilic"
"Spiral ganglion The spiral (cochlear) ganglion is the group of nerve cells that serve the sense of hearing by sending a representation of sound from the cochlea to the brain. The cell bodies of the spiral ganglion neurons are found in the modiolus, the conical shaped central axis in the cochlea. Neurons whose cell bodies lie in the spiral ganglion are strung along the bony core of the cochlea, and send fibers (axons) into the central nervous system (CNS). These bipolar neurons are the first neurons in the auditory system to fire an action potential, and supply all of the"
"the central nervous system form the cochlear nerve. Spiral ganglion The spiral (cochlear) ganglion is the group of nerve cells that serve the sense of hearing by sending a representation of sound from the cochlea to the brain. The cell bodies of the spiral ganglion neurons are found in the modiolus, the conical shaped central axis in the cochlea. Neurons whose cell bodies lie in the spiral ganglion are strung along the bony core of the cochlea, and send fibers (axons) into the central nervous system (CNS). These bipolar neurons are the first neurons in the auditory system to fire"
"are located in the prosoma. On the underside of the prosoma, six pairs of appendages occur, the first of which (the small pincers or chelicerae) are used to pass food into the mouth, which is located in the middle of the underside of the cephalothorax, between the chelicerae. Although most arthropods have mandibles, the horseshoe crab is jawless. The second pair of appendages, the pedipalps, are used as walking legs; in males they are tipped with 'claspers', which are used during mating to hold onto the female's carapace. The remaining four pairs of appendages are the 'pusher legs', also used"
"occurring around 4 kHz. As the organ of hearing, the cochlea consists of two membranes, Reissner’s and the basilar membrane. The basilar membrane moves to audio stimuli through the specific stimulus frequency matches the resonant frequency of a particular region of the basilar membrane. The movement the basilar membrane displaces the inner hair cells in one direction, which encodes a half-wave rectified signal of action potentials in the spiral ganglion cells. The axons of these cells make up the auditory nerve, encoding the rectified stimulus. The auditory nerve responses select certain frequencies, similar to the basilar membrane. For lower frequencies,"
"stapedius muscle is activated in response to sound. The middle ear still contains the sound information in wave form; it is converted to nerve impulses in the cochlea. The inner ear consists of the cochlea and several non-auditory structures. The cochlea has three fluid-filled sections (i.e. the ""scala media, scala tympani and scala vestibuli)"", and supports a fluid wave driven by pressure across the basilar membrane separating two of the sections. Strikingly, one section, called the cochlear duct or ""scala media,"" contains endolymph. Endolymph is a fluid similar in composition to the intracellular fluid found inside cells. The organ of"
"ear and throat. The primary function of the middle ear is to efficiently transfer acoustic energy from compression waves in air to fluid–membrane waves within the cochlea. The middle ear contains three tiny bones known as the ossicles: ""malleus"", ""incus"", and ""stapes"". The ossicles were given their Latin names for their distinctive shapes; they are also referred to as the ""hammer"", ""anvil"", and ""stirrup"", respectively. The ossicles directly couple sound energy from the ear drum to the oval window of the cochlea. While the stapes is present in all tetrapods, the malleus and incus evolved from lower and upper jaw"
"Eardrum In the anatomy of humans and various other tetrapods, the eardrum, also called the tympanic membrane or myringa, is a thin, cone-shaped membrane that separates the external ear from the middle ear. Its function is to transmit sound from the air to the ossicles inside the middle ear, and then to the oval window in the fluid-filled cochlea. Hence, it ultimately converts and amplifies vibration in air to vibration in fluid. The malleus bone bridges the gap between the eardrum and the other ossicles. Rupture or perforation of the eardrum can lead to conductive hearing loss. Collapse or retraction"
"form an opening; in most tetrapods, this breach is never quite completed, and the final vestige of tissue separating it from the outside world becomes the eardrum. The inner part of the spiracle, still connected to the pharynx, forms the eustachian tube. In reptiles, birds, and early fossil tetrapods, there is a single auditory ossicle, the columella ( that is homologous with the stapes, or ""stirrup"" of mammals). This is connected indirectly with the eardrum via a mostly cartilaginous extracolumella and medially to the inner-ear spaces via a widened footplate in the fenestra ovalis. The columella is an evolutionary derivative"
"It is placed at the bottom of a funnel-shaped depression (the round window niche) and, in the macerated bone, opens into the cochlea of the internal ear; in the fresh state it is closed by a membrane, the secondary tympanic membrane (Latin: ""membrana tympani secundaria"", or ""membrana fenestra cochleae"") or round window membrane, which is a complex saddle point shape. The visible central portion is concave (curved inwards) toward the tympanic cavity and convex (curved outwards) toward the cochlea; but towards the edges, where it is hidden in the round window niche, it curves the other way. This membrane consists"
"via the pharyngeal opening of the Eustachian tube. The inner ear contains the otolith organs—the utricle and saccule—and the semicircular canals belonging to the vestibular system, as well as the cochlea of the auditory system. The outer ear is the external portion of the ear and includes the fleshy visible pinna (also called the auricle), the ear canal, and the outer layer of the eardrum (also called the tympanic membrane). The pinna consists of the curving outer rim called the helix, the inner curved rim called the antihelix, and opens into the ear canal. The tragus protrudes and partially obscures"
"about one atom diameter determined for cochlear cells; newer investigation indicated that such a sensitivity may have been the result of artifacts, with the actual sensitivity being comparable to the cochlea. In cockroaches ""Blaberus discoidalis"" and ""Blattella germanica"", the organ has the shape of a fan that is placed across the limb. Much of its volume is filled with discoidal cells that serve accessory purposes; they are placed between an epidermal cell layer attached to the cuticle and connective tissue. Sensory structures called chordotonal sensilla are involved in the perception of movement proper and contain a neuron per sensillum, about"
"Mushroom bodies The mushroom bodies or corpora pedunculata are a pair of structures in the brain of insects, other arthropods, and some annelids (notably the ragworm ""Platynereis dumerilii""). They are also known to play a role in olfactory learning and memory. In most insects, the mushroom bodies and the lateral horn are the two higher brain regions that receive olfactory information from the antennal lobe via projection neurons. Mushroom bodies are usually described as neuropils, i.e. as dense networks of neuronal processes (dendrite and axon terminals) and glia. They get their name from their roughly hemispherical ""calyx"", a protuberance that"
"not clearly defined as a head but contains the sense organs, brain and pharynx. Cilia are found around the mouth and on the ventral surface of the head and body. The trunk contains the gut and the reproductive organs. At the posterior end of the body are two projections with cement glands that serve in adhesion. This is a double-gland system where one gland secretes the glue and another secretes a de-adhesive agent to sever the connection. In the Macrodasyida, there are additional adhesive glands at the anterior end and on the sides of the body. The body wall consists"
"they continue to the lateral lemniscus, then the inferior colliculus, then the medial geniculate body, before finally arriving at the primary auditory cortex. Trapezoid body The trapezoid body (the ventral acoustic stria) is part of the auditory pathway where some of the axons coming from the cochlear nucleus (specifically, the anterior cochlear nucleus) decussate (cross over) to the other side before traveling on to the superior olivary nucleus. This is believed to help with localization of sound. The trapezoid body is located in the caudal pons, or more specifically the pontine tegmentum. It is situated between the pontine nucleus and"