DOCSLIB.ORG

Sound Sensitivity of the Saccule for Low Frequencies in Healthy Adults

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Sound Sensitivity of the Saccule for Low Frequencies in Healthy Adults Hindawi Publishing Corporation ISRN Otolaryngology Volume 2013, Article ID 429680, 6 pages http://dx.doi.org/10.1155/2013/429680 Research Article Sound Sensitivity of the Saccule for Low Frequencies in Healthy Adults Seyede Faranak Emami,1 Akram Pourbakht,2 Ahmad Daneshi,3 Kianoush Sheykholeslami,4 Hessamedin Emamjome,5 and Mohammad Kamali6 1 Department of Audiology, School of Rehabilitation, Iran University of Medical Sciences, Mirdamad Street, 98, Tehran 1545913187, Iran 2 Department of Audiology, Rehabilitation Research Center, School of Rehabilitation Sciences, Iran University of Medical Sciences, Tehran, Iran 3 ENT-Head and Neck Research Center, Hazrat Rasoul Akram Hospital, Iran University of Medical Sciences, Tehran, Iran 4 Department of Surgery, University of Illinois, Rockford, USA 5 Audiology Research Center, Hazrat Rasoul Akram Hospital, Iran University of Medical Sciences, Tehran, Iran 6 Rehabilitation Research Center, School of Rehabilitation Sciences, Iran Univessity of Medical Sciences, Tehran, Iran Correspondence should be addressed to Ahmad Daneshi; [email protected] Received 18 June 2013; Accepted 12 July 2013 Academic Editors: G. G. Ferri, S. L. Halum, and S. C. Winter Copyright © 2013 Seyede Faranak Emami et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Approximately 80 years ago John Tait speculated about a possible auditory role for the otolith organs in humans those days, there was no direct evidence for that idea. This time is for us to review and research. Then, the objective of our study was to investigate saccular hearing in healthy adults. We selected twenty healthy controls and twenty-four dizzy cases. Assessment comprised of audiologic evaluations, cervical vestibular evoked myogenic potentials (cVEMPs), and recognition of spoken phonemes in white noise (Rsp in wn). In the case group (a total of 48 ears), the cVEMPs abnormalities were all unilateral (24 affected ears and 24 contralateral unaffected ears). Affected ears with decreased vestibular excitability as detected by abnormal cVEMPs had decreased Rsp in wn (mean = 60.78 ± 8.33), whereas both unaffected (mean = 96.24 ± 2.4) and control ears (mean = 96.24 ± 2.4)presented normal results. The correlation between RSP in wn and p13 latencies was significant ( < 0.05, = −0.551). The peak-to-peak amplitudes showed significant correlation to RSP in wn ( < 0.05, = 0.307). The correlation between RSP in wn and the latencies of n23 was significant ( < 0.05, = −0.493). We concluded in presence of severe competing noise, saccule has a facilitating role for cochlea and can improve to detection of loud low-frequencies. 1. Introduction Intense air-conducted stimulations with low frequen- cies (between 50 and 800 Hz) may evoke the continuous There are afferent fibers in the vestibular nerve of amniotes responsesinthehumansaccularneurons.Therangeof (reptiles, birds, and mammals) that respond to sound at levels acoustic sensitivity of the sacculus happens to coincide with within the normal range of hearing. The ascending auditory the range of voice pitch, for male voices between 80 and pathway (inner ear, cochlear nucleus, medulla, midbrain, 200Hzandupto400Hzforfemales.Also,thefirstformant thalamus,andcerebrum)ofamniotesisorganizedsimilarly of our voice falls within the range of saccular sensitivity to those of anamniotes (fish and amphibians). Convergent [4–6]. Thus, given the proximity of the ear to the larynx, neuroanatomical specializations in two species may reflect it is possible that saccular responses may be obtained to common functional requirements [1, 2]. These structures an individual’s own vocalisations, particularly for singing. have retained sound sensitivity in man and primates [3, 4]. Another possibility is that responses are obtained when there 2 ISRN Otolaryngology are large groups of individuals vocalising together, such as in completed for the one test, subjects were given a short break a choir or a crowd at a concert or sporting event [6–8]. and the whole procedure repeated for another. The study was On the other hand, most acoustically responsive fibers approved by the IRAN university ethics committee. in the inferior vestibular nerve have irregular spontaneous activity and originate in the saccule. These fibers traced 2.2. Ethical Considerations. Our study was on human sub- centrally arborized extensively in vestibular nuclei and ven- jects, so to minimize harms and risks and maximize benefits tromedial to the cochlear nucleus. Then, mammalian saccule and respect human dignity, privacy, autonomy, immunity, responds to sound and sends acoustic information to the safety, respectability, and satisfaction, we took human precau- central nervous system [2–9], including bulbospinal, brain- tions with our case-control groups and strived to distribute stem, cerebellum, higher centres up to the hypothalamus [2, the benefits and burdens of research fairly. In addition, our 6, 7], and medial and superior temporal gyrus [10]. Therefore, research did not present the work of others as their own or the objective of this study was to investigate saccular hearing did not fail to give appropriate credit for the work of others in healthy adults. through citations. 2.3. Assessments. Evaluation for screening of case group, 2. Materials and Methods consisted of pure tone audiometry, tympanometry and acous- 2.1. Participants. This case-control study consisted of twenty tic reflex test, auditory brainstem response, electronystagmog- healthy controls (11 females, 9 males) and twenty-four dizzy raphy, word recognition scores (Rsp) in quiet, and cervical patients (14 females and 10 males), which were screened from vestibular evoked myogenic potentials (cVEMPs), which were of sixty-seven patients with benign paroxysmal positional employed for reviewing our inclusion criteria. Recognition of vertigo and migraineurs. They were presented to the Audi- spoken phonemes in white noise (Rsp in wn) and cVEMPs ology Department of Hazrat Rasoul Akram hospital of IRAN involved assessment of our main variables. university of medical sciences (Tehran, Iran), from May 2012 The devices were diagnostic pure tone audiometry toDecember2012.Wescreenedallvolunteereligiblepatients (Madsen:OB-822), impedance acoustic metr (Maico MI 34), about seven months (we could not find previous collected full system of auditory-vestibular evoked potentials (Labat Epic-plus). works and used of censes method for sampling strategy). − The diagnose of patients with benign paroxysmal posi- Pure tone thresholds in the normal range ( 10 to tional vertigo was based on medical history and findings 25 dBHL) were obtained from each person’s over the fre- of characteristic nystagmus (torsional up beating nystagmus quency range of 250–8000 Hz [13]. Tympanometry served to with latency and fatigue lasting less than 1 min) and subjective evaluate the middle ear status [14]. Acoustic reflex test (Ipsi- vertigointheDix-Hallpiketest[11, 12]. lateral and contralateral) was conducted to eliminate the pos- In migraineurs vestibular dysfunctions were connected sibility of any additional auditory olivocochlear pathology. with nystagmus, and with episodic vertigo, or a variety of The normal range considered from about 85 to 100 dB SPL combinations of headache/vertigo. A number of patients for pure tone stimuli [15]. Auditory brainstem response was reported that their symptoms were worse with achieved head done to exclude the probability of any additional brainstem status, but this is not confused with BPPV,since patients with pathology. We considered the responses to be abnormal when migrainous vertigo were nauseated or phonophobic during peaks III and/or V were absent or when the peak to peak I– attacks [11, 12]. V exceeded the normal limits of our laboratory (4.40 ms for The exclusion criteria consisted of history of ear infections females, 4.58 ms for males). Electronystagmography used to and middle ear diseases, which can interfere with cVEMPs reject the possibility of any additional vestibular pathology. measurements, and conditions that can cause abnormal The battery of electronystagmography tests included assess- auditory function. To this list were included history of head ment of the central vestibular and vestibulocular systems trauma, ototoxic drugs, otosclerosis, labyrinthitis, cardiac with evaluation of gaze [12]. Word recognition scores in and metabolic diseases, heart failure, anemia, hypothy- quiet presented by one female (monitoring of live voice). The roidism, hyperthyroidism, diabetes mellitus, hypertension, normal scores were 96–100% [16]. and various neurological diseases (vertebrobasilar insuffi- ciency, temporal lobe epilepsy, multiple sclerosis, central 2.3.1. Cervical Vestibular Evoked Myogenic Potentials nervous system tumors, and cerebellar infarction, among (cVEMPs). During the cVEMPs, recording patients were others). instructed to turn and hold their heads as far as possible The inclusion criteria involved normal function of hear- toward the side contralateral to the stimulated ear. At ing, middle ear pressure, olivocochlear and auditory brain- that point, the overall electromyogenic activity of the stem pathway, with abnormal function of saccule. sternocleidomastoid muscle was set as the reference level A handedness questionnaire was also administered. All of the tonic contraction. Patients were asked to maintain
Load more

Recommended publications
  • Common Vestibular Function Tests
    Common Vestibular Function Tests Authors: Barbara Susan Robinson, PT, DPT; Lisa Heusel-Gillig PT DPT NCS Fact Sheet The purpose of Vestibular Function Tests (VFTs) is to determine the health of the vestibular portion of the inner ear. These tests are commonly performed by ENTs, Audiologists, and Otolaryngologists Electronystagmography or Videonystagmography Electronystagmography (ENG test) or Videonystagmography (VNG test) evaluate the inner ear. Both record eye movements during a group of tests in light and dark rooms. During the ENG test, small electrodes are placed on the skin near the eyes to record eye movements. For the VNG test, eye movements are recorded by a video camera mounted inside of goggles that are worn during testing. ENG and VNG tests evaluate eye movements while following a visual target (tracking Produced by test) or during body and head position changes (positional test). The caloric test evaluates eye movements in response to cool or warm air (or water) placed in the ear canal. If there is no response to warm or cool air or water, ice water may be used in order to try to produce a response. The caloric test determines the difference between the function of the left and right inner ear. During this test, you may experience dizziness or nausea. You may be asked questions (math questions, city names, alphabet tasks) to distract you in order to get the best results. A Special Interest Group of Contact us: ANPT Other Common Vestibular Function Tests 5841 Cedar Lake Rd S. The rotary chair test is used along with the VNG to confirm the diagnosis and assess Ste 204 compensation of the vestibular system.
    [Show full text]
  • Anatomy of the Ear ANATOMY & Glossary of Terms
    Anatomy of the Ear ANATOMY & Glossary of Terms By Vestibular Disorders Association HEARING & ANATOMY BALANCE The human inner ear contains two divisions: the hearing (auditory) The human ear contains component—the cochlea, and a balance (vestibular) component—the two components: auditory peripheral vestibular system. Peripheral in this context refers to (cochlea) & balance a system that is outside of the central nervous system (brain and (vestibular). brainstem). The peripheral vestibular system sends information to the brain and brainstem. The vestibular system in each ear consists of a complex series of passageways and chambers within the bony skull. Within these ARTICLE passageways are tubes (semicircular canals), and sacs (a utricle and saccule), filled with a fluid called endolymph. Around the outside of the tubes and sacs is a different fluid called perilymph. Both of these fluids are of precise chemical compositions, and they are different. The mechanism that regulates the amount and composition of these fluids is 04 important to the proper functioning of the inner ear. Each of the semicircular canals is located in a different spatial plane. They are located at right angles to each other and to those in the ear on the opposite side of the head. At the base of each canal is a swelling DID THIS ARTICLE (ampulla) and within each ampulla is a sensory receptor (cupula). HELP YOU? MOVEMENT AND BALANCE SUPPORT VEDA @ VESTIBULAR.ORG With head movement in the plane or angle in which a canal is positioned, the endo-lymphatic fluid within that canal, because of inertia, lags behind. When this fluid lags behind, the sensory receptor within the canal is bent.
    [Show full text]
  • Balance and Equilibrium, I: the Vestibule and Semicircular Canals
    Anatomic Moment Balance and Equilibrium, I: The Vestibule and Semicircular Canals Joel D. Swartz, David L. Daniels, H. Ric Harnsberger, Katherine A. Shaffer, and Leighton Mark In this, our second temporal bone installment, The endolymphatic duct arises from the en- we will emphasize the vestibular portion of the dolymphatic sinus and passes through the ves- labyrinth, that relating to balance and equilib- tibular aqueduct of the osseous labyrinth to rium. Before proceeding, we must again remind emerge from an aperture along the posterior the reader of the basic structure of the labyrinth: surface of the petrous pyramid as the endolym- an inner membranous labyrinth (endolym- phatic sac. phatic) surrounded by an outer osseous laby- The utricle and saccule are together referred rinth with an interposed supportive perilym- to as the static labyrinth, because their function phatic labyrinth. We recommend perusal of the is to detect the position of the head relative to first installment before continuing if there are gravity (5–7). They each have a focal concen- any uncertainties in this regard. tration of sensory receptors (maculae) located The vestibule, the largest labyrinthine cavity, at right angles to each other and consisting of measures 4 to 6 mm maximal diameter (1–3) ciliated hair cells and tiny crystals of calcium (Figs 1–3). The medial wall of the vestibule is carbonate (otoliths) embedded in a gelatinous unique in that it contains two distinct depres- mass. These otoliths respond to gravitational sions (Fig 4). Posterosuperiorly lies the elliptical pull; therefore, changes in head position distort recess, where the utricle is anchored.
    [Show full text]
  • Acoustically Responsive Fibers in the Vestibular Nerve of the Cat
    The Journal of Neuroscience, October 1994, 74(10): 6056-6070 Acoustically Responsive Fibers in the Vestibular Nerve of the Cat Michael P. McCue1v2*a and John J. Guinan, Jr.r.2.3-4 ‘Eaton-Peabody Laboratory of Auditory Physiology, Department of Otolaryngology, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts 02114, 2Harvard-MIT Division of Health Science and Technology and Research Laboratory of Electronics, and 3Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, and 4Department of Otology and Laryngology, Harvard Medical School, Boston, Massachusetts 02115 Recordings were made from single afferent fibers in the and levels within the normal range of human hearing. We inferior vestibular nerve, which innervates the saccule and suggest a number of auditory roles that these fibers may posterior semicircular canal. A substantial portion of the fi- play in the everyday life of mammals. bers with irregular background activity increased their firing [Key words: saccule, otoliths, auditory system, mamma- in response to moderately intense clicks and tones. lian sound reception, middle-ear muscles, cochlear nucleus] In responsive fibers, acoustic clicks evoked action poten- tials with minimum latencies of I 1 .O msec. Fibers fell into The vertebrate inner ear contains several senseorgans involved two classes, with the shortest latency either to condensation in the maintenance of equilibrium and the detection of vibra- clicks (PUSH fibers) or to rarefaction clicks (PULL fibers). tion. The precise sensory role assumedby homologous organs Low-frequency (800 Hz) tone bursts at moderately high sound varies among species.For example, the sacculeis thought to act levels (>80 dB SPL) caused synchronization of spikes to asa linear accelerometerin mammals(Fernindez and Goldberg, preferred phases of the tone cycle.
    [Show full text]
  • VESTIBULAR SYSTEM (Balance/Equilibrium) the Vestibular Stimulus Is Provided by Earth's Gravity, and Head/Body Movement. Locate
    VESTIBULAR SYSTEM (Balance/Equilibrium) The vestibular stimulus is provided by Earth’s gravity, and head/body movement. Located in the labyrinths of the inner ear, in two components: 1. Vestibular sacs - gravity & head direction 2. Semicircular canals - angular acceleration (changes in the rotation of the head, not steady rotation) 1. Vestibular sacs (Otolith organs) - made of: a) Utricle (“little pouch”) b) Saccule (“little sac”) Signaling mechanism of Vestibular sacs Receptive organ located on the “floor” of Utricle and on “wall” of Saccule when head is in upright position - crystals move within gelatinous mass upon head movement; - crystals slightly bend cilia of hair cells also located within gelatinous mass; - this increases or decreases rate of action potentials in bipolar vestibular sensory neurons. Otoconia: Calcium carbonate crystals Gelatinous mass Cilia Hair cells Vestibular nerve Vestibular ganglion 2. Semicircular canals: 3 ring structures; each filled with fluid, separated by a membrane. Signaling mechanism of Semicircular canals -head movement induces movement of endolymph, but inertial resistance of endolymph slightly bends cupula (endolymph movement is initially slower than head mvmt); - cupula bending slightly moves the cilia of hair cells; - this bending changes rate of action potentials in bipolar vestibular sensory neurons; - when head movement stops: endolymph movement continues for slightly longer, again bending the cupula but in reverse direction on hair cells which changes rate of APs; - detects “acceleration”
    [Show full text]
  • Anatomic Moment
    Anatomic Moment Hearing, I: The Cochlea David L. Daniels, Joel D. Swartz, H. Ric Harnsberger, John L. Ulmer, Katherine A. Shaffer, and Leighton Mark The purpose of the ear is to transform me- cochlear recess, which lies on the medial wall of chanical energy (sound) into electric energy. the vestibule (Fig 3). As these sound waves The external ear collects and directs the sound. enter the perilymph of the scala vestibuli, they The middle ear converts the sound to fluid mo- are transmitted through the vestibular mem- tion. The inner ear, specifically the cochlea, brane into the endolymph of the cochlear duct, transforms fluid motion into electric energy. causing displacement of the basilar membrane, The cochlea is a coiled structure consisting of which stimulates the hair cell receptors of the two and three quarter turns (Figs 1 and 2). If it organ of Corti (Figs 4–7) (4, 5). It is the move- were elongated, the cochlea would be approxi- ment of hair cells that generates the electric mately 30 mm in length. The fluid-filled spaces potentials that are converted into action poten- of the cochlea are comprised of three parallel tials in the auditory nerve fibers. The basilar canals: an outer scala vestibuli (ascending spi- membrane varies in width and tension from ral), an inner scala tympani (descending spi- base to apex. As a result, different portions of ral), and the central cochlear duct (scala media) the membrane respond to different auditory fre- (1–7). The scala vestibuli and scala tympani quencies (2, 5). These perilymphatic waves are contain perilymph, a substance similar in com- transmitted via the apex of the cochlea (helico- position to cerebrospinal fluid.
    [Show full text]
  • Physiology of the Inner Ear Balance
    § Te xt § Important Lecture § Formulas No.15 § Numbers § Doctor notes “Life Is Like Riding A § Notes and explanation Bicycle. To Keep Your Balance, You Must Keep Moving” 1 Physiology of the inner ear balance Objectives: 1. Understand the sensory apparatus of the inner ear that helps the body maintain its postural equilibrium. 2. The mechanism of the vestibular system for coordinating the position of the head and the movement of the eyes. 3. The function of semicircular canals (rotational movements, angular acceleration). 4. The function of the utricle and saccule within the vestibule (respond to changes in the position of the head with respect to gravity (linear acceleration). 5. The connection between the vestibular system and other structure (eye, cerebellum, brain stem). 2 Control of equilibrium } Equilibrium: Reflexes maintain body position at rest & movement through receptors of postural reflexes: 1. Proprioceptive system (Cutaneous sensations). 2. Visual (retinal) system. 3. Vestibular system (Non auditory membranous labyrinth1). 4. Cutaneous sensation. } Cooperating with vestibular system wich is present in the semicircular canals in the inner ear. 3 1: the explanation in the next slide. • Ampulla or crista ampullaris: are the dilations at the end of the semicircular canals and they affect the balance. • The dilations connect the semicircular canals to the cochlea utricle Labyrinth and saccule: contain the vestibular apparatus (maculla). Bony labyrinth • bony cochlea, vestibule & 3 bony semicircular canals. • Enclose the membranous labyrinth. Labyrinth a. Auditory (cochlea for hearing). b. Non-auditory for equilibrium (Vestibular apparatus). composed of two parts: • Vestibule: (Utricle and Saccule). • Semicircular canals “SCC”. Membranous labyrinth • Membranous labyrinth has sensory receptors for hearing and equilibrium • Vestibular apparatus is responsible for equilibrium 4 Macula (otolith organs) of utricle and saccule } Hair cell synapse with endings of the vestibular nerve.
    [Show full text]
  • The Other Senses
    COGS 17 Fall 2009 The Other Senses Mary ET Boyle, Ph.D. Department of Cognitive Science UCSD Peripheral Vestibular Structure: • Inner ear miniaturized accelerometers inertial guidance devices Continually reporting information about: motions and position of head and body Information goes to: brainstem cerebellum somatic sensory cortices 1 Central Vestibular Structure: • Vestibular Nuclei Directly controls motor neurons controlling: extraocular cervical postural Important for: stabilization of gaze head orientation posture during movements The Vestibular Labyrinth: • Main peripheral component Connected with cochlea Uses same specialized hair cells Transduce physical motion into neural impulses head movements inertial effects due to gravity ground-borne vibrations Vestibular endolymph (like cochlear endolymph) high in K+ and low in Na+ 2 Vestibular navigation • Translational movements are in terms of x, y, z Saccule Utricle Rotational movements roll, pitch, yaw • Roll – tumbling left or right -- move your head from your left to your right shoulder • Pitch – nod your head “yes” • Yaw – shake your head “no” Semicircular canals 3 The Vestibular Labyrinth – otolith organs • Two otolith organs - (vestibular sacs) Utricle – hair cells are located on the floor- horizontal plane Saccule – hair cells are located on the wall – vertical motion •Respond to: Information about the position of the head relative to the body utricle cochlea Vestibulocochlear nerve VIII saccule The Vestibular Labyrinth – semicircular canals • Three semicircular canals- (vestibular sacs) Oriented in three planes Ampullae – located at the base of each of the semicircular canals. •Respond to: Rotational accelerations of the head ampullae cochlea Vestibulocochlear nerve VIII 4 The Vestibular Hair cells Similar to auditory hair cells Mechanically gated transduction Channels located at the tips of the stereocilia Otolithic hair cells Scanning EM of calcium carbonate crystals (otoconia) in the utricular macula of the cat.
    [Show full text]
  • Development and Evolution of the Vestibular Sensory Apparatus of the Mammalian Ear
    Journal of Vestibular Research 15 (2005) 225–241 225 IOS Press Development and evolution of the vestibular sensory apparatus of the mammalian ear Kirk W. Beisel, Yesha Wang-Lundberg, Adel Maklad and Bernd Fritzsch ∗ Creighton University, Omaha, NE and BTNRH, Omaha, NE, USA Received 21 June 2005 Accepted 3 November 2005 Abstract. Herein, we will review molecular aspects of vestibular ear development and present them in the context of evolutionary changes and hair cell regeneration. Several genes guide the development of anterior and posterior canals. Although some of these genes are also important for horizontal canal development, this canal strongly depends on a single gene, Otx1. Otx1 also governs the segregation of saccule and utricle. Several genes are essential for otoconia and cupula formation, but protein interactions necessary to form and maintain otoconia or a cupula are not yet understood. Nerve fiber guidance to specific vestibular end- organs is predominantly mediated by diffusible neurotrophic factors that work even in the absence of differentiated hair cells. Neurotrophins, in particular Bdnf, are the most crucial attractive factor released by hair cells. If Bdnf is misexpressed, fibers can be redirected away from hair cells. Hair cell differentiation is mediated by Atoh1. However, Atoh1 may not initiate hair cell precursor formation. Resolving the role of Atoh1 in postmitotic hair cell precursors is crucial for future attempts in hair cell regeneration. Additional analyses are needed before gene therapy can help regenerate hair cells, restore otoconia, and reconnect sensory epithelia to the brain. Keywords: Ear, development, sensory epithelia, sensory neurons, otoconia, cupula 1. Introduction c) Sound reaches the cochlea where the basilar membrane motion and hair cell stimulation con- verts specific frequencies into tonotopic informa- The mammalian ear contains three sensory systems: tion that encodes place of cochlear stimulation a) Angular acceleration perception is accomplished and intensity.
    [Show full text]
  • Balance and Equilibrium, II: the Retrovestibular Neural Pathway
    Anatomic Moment Balance and Equilibrium, II: The Retrovestibular Neural Pathway Joel D. Swartz, David L. Daniels, H. Ric Harnsberger, John L. Ulmer, Steven Harvey, Katherine A. Shaffer, and Leighton Mark In this article, we will consider the anatomy of nerve within this quadrant (Fig 3). This ana- the retrovestibular pathways: the superior and tomic arrangement allows for surgical denerva- inferior vestibular nerves and related intraaxial tion of the posterior semicircular canal (singular structures. The reader is encouraged to review neurectomy), a procedure indicated for many previous installments if questions arise regard- patients with chronic benign positional vertigo ing terminology. (cupulolithiasis) (4). The internal auditory canal (IAC) is highly The vestibular (Scarpa’s) ganglion is situated variable in size, shape, and orientation (1). As a within the IAC and is responsible for mediation general rule, there is symmetry between the of afferent and efferent impulses of the saccule, right and left canals in the same person. The utricle, and all three semicircular canals (3). As IAC is defined as having a porus (meatus) me- such, the vestibular nerve has five terminal dially along the petrous surface and a fundus branches. Four vestibular nuclei are located in laterally abutting the labyrinth. At the fundus, a the brain stem at the pontomedullary junction transverse (falciform) crest separates the canal medial to the cochlear nuclei at the level of the into superior and inferior compartments. Fur- floor of the fourth ventricle (2, 5) (Fig 6). Fibers thermore, a vertical crest (Bill’s bar) subdivides of the vestibular nerves synapse in these nuclei. the superior compartment into anterior and Activity within the brain stem is quite complex posterior portions (Figs 1 and 2).
    [Show full text]
  • Vestibular Sense.Pptx
    Chapter 9 Majority of illustraons in this presentaon are from Biological Psychology 4th edi3on (© Sinuer Publicaons) Ves3bular Sense 1. Ves3bular sense or the sense of equilibrium and balance works for birds in air, fish in water, and terrestrial animals on land. 2. Sensory organ that senses gravity and acceleraon is contained in the inner ear. Three Semicircular Canals 2 Semicircular Canals The inner ear contains three semicircular canals, utricle and saccule. These organs are fluid filled (endolymph) and sense postural 3lts as well as linear mo3on in space. 3 1 Angular Movement Three semicircular canals, horizontal (h) which is leveled when the head is upright; anterior (a) is in the front and posterior (p) lie at the back orthogonal to each other. a Crus h p Commune Ampulla 4 Angular Acceleraon During angular acceleraon in any plane results in movement of the endolymph sensing this angular moon. www.kpcnews.net 5 Ves3bulocular Reflex The ves3bulocular reflex helps maintain the body by fixang the eyes on an object with movement of the head. Both angular and linear acceleraon signals are used in the ves3bulocular reflex. 6 2 Ampulla Three ampullae at the end of the three semicircular canals that contain the sensory hair cells (Humans = 7000 cells). Body rotaons are registered by hair cells when endolymph moves. Capula Ampulla Endolymph Endolymph Semicircular Hair cells canal Hair cells 7 Horizontal & Ver3cal Movement www.askamathemacian.com Horizontal and ver3cal acceleraon is sensed by saccule and utricle in the inner ear. 8 Utricle & Otolithic Membrane 1. Utricle (uterus, 3 mm) senses linear acceleraon in the horizontal plane.
    [Show full text]
  • Solitary Hair Cells Are Distributed Throughout the Extramacular Epithelium in the Bullfrog’S Saccule
    JARO 01: 172±182 (2000) DOI: 10.1007/s101620010037 Solitary Hair Cells Are Distributed Throughout the Extramacular Epithelium in the Bullfrog's Saccule JONATHAN E. GALE,JASON R. MEYERS, AND JEFFREY T. CORWIN Department of Otolaryngology±HNS and Department of Neuroscience, University of Virginia School of Medicine, Charlottesville, VA 22908, USA Received: 27 March 2000; Accepted: 5 June 2000; Online publication: 29 August 2000 ABSTRACT lium that has not been considered capable of giving rise to hair cells. The frog inner ear contains eight sensory organs that Keywords: hair cell, vestibular, balance, bullfrog, amphib- provide sensitivities to auditory, vestibular, and ian, sacculus, vital dye ground-borne vibrational stimuli. The saccule in bull- frogs is responsible for detecting ground- and air- borne vibrations and is used for studies of hair cell physiology, development, and regeneration. Based on INTRODUCTION hair bundle morphology, a number of hair cell types have been defined in this organ. Using immunocyto- The saccule of the bullfrog, Rana catesbieana, is sensi- chemistry, vital labeling, and electron microscopy, we tive to substrate and air-borne vibrations (Lewis et al. have characterized a new hair cell type in the bullfrog 1985). The saccular macula has been used for the study saccule. A monoclonal antibody that is specific to hair of hair cell anatomy and development (Hillman and cells revealed that a population of solitary hair cells Lewis 1971; Lewis and Li 1973, 1975; Kelley et al. 1992), exists outside the sensory macula in what was pre- hair cell physiology (Hudspeth and Corey 1977; Corey viously thought to be nonsensory epithelium.
    [Show full text]