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Vestibular Respiratory Regulation
Published in Alan D. Miller, Armand L. Bianchi, Beverly P. Bishop, Neural Control of the Respiratory Muscles, 2019
The hair cells of semicircular canals are confined to a swelling, called an ampulla. The stereocilia are embedded in a gelatinous mass called the cupula, which has the same specific gravity as the surrounding endolymph. The ensemble of hair cells and cupula, which comprise the canal sensory organ (referred to as a crista ampullaris), completely close the lumen of the semicircular canal. Within the crista ampullaris, all of the hair cells have the same morphological polarization (i.e., their kinocilia face in the same direction). As a result, a head movement will have roughly equivalent effects on intracellular potential and neurotransmitter release by all hair cells in a semicircular canal.
Anatomy of the Cochlea and Vestibular System: Relating Ultrastructure to Function
Published in John C Watkinson, Raymond W Clarke, Christopher P Aldren, Doris-Eva Bamiou, Raymond W Clarke, Richard M Irving, Haytham Kubba, Shakeel R Saeed, Paediatrics, The Ear, Skull Base, 2018
The maculae of the utricle and saccule are flat sheets of epithelium that are oriented at right angles to each other (Figure 47.2a), the utricle in the anterior–posterior plane, the saccule in the superior–inferior. The utricular macula is approximately U-shaped and the saccular macula, in mammals, is almost S-shaped (Figure 47.3a,b). The cristae ampullares of the semicircular canals are saddle-shaped epithelial mounds (Figure 47.3c) contained within swellings, the ampullae, which open to the utricle at one end. The cell bodies of the nerves that innervate the sensory cells of the vestibular system are collected together in Scarpa’s or vestibular ganglion, which is just external to the medial wall of the inner ear (Figure 47.2a).
Discussions (D)
Published in Terence R. Anthoney, Neuroanatomy and the Neurologic Exam, 2017
Williams and Warwick note that the maculae are “often referred to as organs of static balance …, whereas the ampullary crests [cristae ampullares] are called organs of kinetic balance” (1980, p. 1205). Similarly, Matzke and Foltz refer to the maculae as “static receptors” and to the cristae as “dynamic receptors” (1983, p. 53). If one assumes that these authors are using the terms “organs of static balance” and “static receptors” as synonyms for “static labyrinth” and using the terms “organs of kinetic balance” and “dynamic receptors” as synonyms for “kinetic labyrinth,” then their statements represent additional examples of defining the static labyrinth and the kinetic labyrinth at the level of the maculae and cristae ampullares, respectively. This assumption may not be valid, however. Romero-Sierra, as cited above, defines the “static labyrinth” and “kinetic labyrinth” at the level of the utricle, saccule, and semicircular ducts; yet he refers to each macula as a “static organ” and to each crista ampullaris as a “kinetic sensory organ” (1986, p. 330).
Cisplatin ototoxicity and role of antioxidant on its prevention
Published in Hearing, Balance and Communication, 2020
Anna Rita Fetoni, Laura Astolfi
It is well described that cisplatin induces hearing loss mainly impairing outer hear cells (OHCs) in the basal turns affecting the highest frequencies [6,8,28–30], reducing the endocochlear potential as shown by dysfunction of the stria vascularis [9,10] and degenerating the spiral ganglion [32,33].To date, several rodents were used to study cisplatin toxicity and its prevention, but it is still being investigated the best protocol mimicking the clinical therapy [28,34]. In animal models only the high cisplatin cumulative doses (12–16 mg/kg) cause ototoxicity, but the other adverse effects lead to high mortality ratio limiting the investigation to acute consequences [29,35]. For this reason, several studies focussed to understand the different effects of cumulative doses versus one bolus injection, in order to mimic the clinical protocols and to avoid the high mortality [28,34]. Concerning the vestibular function, only few studies investigated this issue, and cisplatin seems to impair macula and crista ampullaris functions [36–38]. In a mouse model no vestibular impairments were detected; thus, the authors speculated that the use of different animal models and treatment protocols could have influenced the observed results [34].
Clinical long-term effects of surgical treatment for intractable Meniere’s disease: a more than 13-year follow-up after pressure treatment and further surgical treatment for intractable vertigo
Published in Acta Oto-Laryngologica, 2019
Fang Liu, Weining Huang, Kai Chen
In recent years, semicircular canal occlusion applied to effectively control the vertigo attacks of intractable Meniere’s disease [11,12]. Our results show that no rotational vertigo occurred in Patient No. 11 and 16 after TSCO during the follow-up period. Moreover, both of them showed the complete blockage for the ipsilateral three semicircular canals of inner ear in MRI and the loss of lateral semicircular canal function in caloric test during one week and three months after TSCO, respectively. First, the rotational vertigo caused by displacement of the crista ampullaris of the semicircular canals is eliminated because the canal occlusion blocks stimulation of the cupulae of the semicircular canals and the endolymph of inner ear cannot be compressed or expanded. Second, the postoperative disequilibrium is compensated for quickly. On one hand, semicircular canal occlusion does not affect the resting potential of vestibular peripheral organs, which is conducive to restoring static and dynamic balance. On the other hand, semicircular canal occlusion does not affect otolithic function and central compensation is established faster.
From Mondini to the latest inner ear malformations’ classifications: an historical and critical review
Published in Hearing, Balance and Communication, 2019
Davide Brotto, Andrea Uberti, Renzo Manara
In 1892, the German Arno Scheibe (1864–1937) described the temporal bone pathology of a congenitally deaf 47-year-old man. The findings included severe dysgenesis of the organ of Corti and atrophy of the nerves of the cochlea, saccule and posterior ampulla, a thinned stria vascularis as a result of absence of cellular elements, rudiments of the tectorial membrane surrounded by epithelial cells, Reissner’s membrane bulging excessively towards the scala vestibuli, a collapsed Reissner’s membrane usually lying down on the stria, a severe dysgenesis of the saccular macula, the collapse of the endolymphatic space within the cochlea and the saccule, while the utricle and three cristae ampullares had a normal architecture. This peculiar abnormality is since then called Scheibe’s dysplasia, or Cochleosaccular dysplasia [8–10].