The vestibular labyrinth of the albino rat: Form and dimensions, and the orientation of the semicircular canals, cristae, and maculae

The extensive remains of large sauropods, excavated in the Upper Jurassic layers of the Tendaguru region of Tanzania, East Africa by Janensch [15], include an intact fossil cast of a vestibular labyrinth and an endocast of the large Brachiosaurus brancai. The approximately 150 million year old labyrinth cast demonstrates clearly a form and organisation congruent in detail to those of extant vertebrate species. Besides the near-orthogonal arrangement of semicircular canals (SCCs), the superior and inferior branches of the vestibulo-acoustic nerve, the endolymphatic duct, the oval and round windows, and the cochlea can be identified. The orientation of the labyrinth in the temporal bone is also equivalent to that of many extant vertebrates. Furthermore, the existence of the twelve cranial nerves can be identified from the endocast. The present study was initiated after the photogrammetric measurement of the skeleton volume of B. brancai [13] yielded a realistic estimate of body mass (74.42 metric tons). Dimensional analysis shows that body mass and average SCC dimensions of B. brancai generally fit with the allometric relationship found in previous studies of extant species. However, the anterior SCC is significantly larger than the allometric relationship would predict. This would indicate greater sensitivity, supporting the idea that the behavioural repertoire must have included much slower pitch movements of the head. These slower movements would most likely have involved flexion of the neck, rather than head pitching about the atlas joint. Pursuing the relationship between body mass and SCC dimensions further, the SCC frequency response is estimated by scaling up from the SCC dimensions of the rhesus monkey; this yields a range between 0.008–26 Hz, approximately one octave lower than for humans.

Download Full-text

Crosslinks between stereocilia in hair cells of the human and guinea pig vestibular labyrinth

The Journal of Laryngology & Otology ◽

10.1017/s002221510010115x ◽

1986 ◽

Vol 100 (12) ◽

pp. 1367-1374 ◽

Cited By ~ 15

Author(s):

David J. Jeffries ◽

James O. Pickles ◽

Michael P. Osborne ◽

Peter H. Rhys-Evans ◽

Spiro D. Comis

Keyword(s):

Guinea Pig ◽

Hair Cells ◽

Semicircular Canals ◽

Sensory Transduction ◽

Hair Bundle ◽

Vestibular Labyrinth ◽

Vestibular Hair Cells ◽

Cuticular Plate ◽

Temporal Bones

AbstractThe saccules and ampullae of the semicircular canals from human and guinea pig temporal bones were fixed in glutaraldehyde without osmium. Crosslinks were seen between stereocilia of the vestibular hair cells, similar to those previously demonstrated in the guinea pig, although an additional set of crosslinks was displayed: first, horizontal crosslinks were seen between adjacent stereocilia, occupying most of the length of the hair bundle; secondly, a single upward-pointing link ran from the apex of each shorter stereocilium into the shaft of the adjacent taller ster-eocilium; thirdly, an extensive array of horizontal links were demonstrated between stereocilia close to their insertion into the cuticular plate. We suggest that these basal crosslinks support the long vestibular stereocilia rendering them more rigid, and that the upwind pointing crosslinks are responsible for the initiation of sensory transduction.

Download Full-text

Melanocytes of the Vestibular Labyrinth and Their Relationship to the Microvasculature

Annals of Otology Rhinology & Laryngology ◽

10.1177/000348947408300518 ◽

1974 ◽

Vol 83 (5) ◽

pp. 685-694 ◽

Cited By ~ 46

Author(s):

Keith A. LaFerriere ◽

I. Kaufman Arenberg ◽

Joseph E. Hawkins ◽

Lars-Göran Johnsson

Keyword(s):

Skin Color ◽

Stria Vascularis ◽

Sensorineural Deafness ◽

Semicircular Canals ◽

Capillary Endothelium ◽

Spiral Ligament ◽

Dark Cell ◽

Intimate Contact ◽

Vestibular Labyrinth ◽

Vasomotor Function

The melanocytes of the vestibular labyrinth as seen in colored guinea pigs show a characteristic pattern of distribution in the wall of the utricle and in the ampullae, but they are not present in the wall of the saccule. They are found mainly in well-vascularized regions of apparent secretory or metabolic importance, including the “dark cell” areas. Their dendrite-like processes are often in intimate contact with the capillaries, although no pinocytotic vesicles or other indications of transfer of substances between the melanocytes and the capillary endothelium are seen under the electron microscope. In the human ear, the apparent density of the melanocytes varies with skin color. They are numerous in the cochlea, especially in the bony wall of the modiolus and on the osseous spiral lamina, and they occur also in Reissner's membrane and in the stria vascularis. In the vestibular system they are found in the wall of the saccule as well as in the utricle, the crus commune, and the ampullae, but not in the semicircular canals. They tend to be diffusely scattered, rather than to form the well-defined, intensely pigmented areas that are characteristic of the guinea pig. Close contacts with capillaries are seen mainly in the tympanic portion of the spiral ligament. The significance of melanin and the melanocytes in the labyrinth is unknown, but both the anatomical relation of certain melanocytes to capillaries, and the biochemical relation of melanin to the catecholamines support the hypothesis that they may have a vasomotor function. Other evidence, including the not infrequent association of sensorineural deafness with hereditary disorders of pigmentation also suggests that the melanocytes may play a role of some biological consequence in the inner ear.

Download Full-text

On the vestibular labyrinth of the albino rat after prolonged rotation

The Journal of Comparative Neurology ◽

10.1002/cne.900410108 ◽

1926 ◽

Vol 41 (1) ◽

pp. 223-251 ◽

Cited By ~ 6

Author(s):

Harley N. Gould

Keyword(s):

Albino Rat ◽

Vestibular Labyrinth

Download Full-text

Electrophysical properties and transfer function of the vestibular labyrinth

Izvestiya vysshikh uchebnykh zavedenii. Fizika ◽

10.17223/00213411/63/11/154 ◽

2020 ◽

pp. 154-161

Author(s):

V.P. Demkin ◽

◽

S.V. Melnichuk ◽

M.D. Akinina ◽

O.V. Demkin ◽

...

Keyword(s):

Experimental Data ◽

Transfer Function ◽

Dynamic Systems ◽

Theoretical Study ◽

Semicircular Canals ◽

Electrical Signal ◽

Electrophysical Properties ◽

Posterior Semicircular Canal ◽

Vestibular Labyrinth ◽

Conductive Properties

We carried out an experimental and theoretical study of the electrical conductive properties of the tissues of the vestibular labyrinth. Using the theory of dynamic systems and experimental data on measurements of the amplitudes of the electrical signal at the end of the vestibular nerve, we calculated the transfer function of the vestibular labyrinth and investigated its frequency dependence. It is shown the transfer function tends to its asymptotic value with increasing frequency. We found that the transfer function of the vestibular labyrinth for stimulating impulses emanating from the electrode located in the posterior semicircular canal is significantly less than for stimulating impulses from the electrodes located in the superior and horizontal semicircular canals.

Download Full-text

The ultrastructure of acinar cells in the external orbital gland of young and old male rats

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100082248 ◽

1978 ◽

Vol 36 (2) ◽

pp. 276-277

Author(s):

R. Carriere

Keyword(s):

Young Adulthood ◽

Acinar Cells ◽

Cell Number ◽

Male Rats ◽

Polyploid Cell ◽

Secretory Cells ◽

Age Changes ◽

Albino Rat ◽

Golgi Membranes ◽

Diploid Cells

The external orbital gland of the albino rat exhibits both sexual dimorphism and histological age changes. In males, many cells attain a remarkable degree of polyploidy and an increase of polyploid cell number constitutes the major age change until young adulthood. The acini of young adults have a small lumen and are composed of tall serous cells. Subsequently, many acini acquire a larger lumen with an irregular outline while numerous vacuoles accumulate throughout the secretory cells. At the same time, vesicular acini with a large lumen surrounded by pale-staining low cuboidal diploid cells begin to appear and their number increases throughout old age. The fine structure of external orbital glands from both sexes has been explored and in considering acinar cells from males, emphasis was given to the form of the Golgi membranes and to nuclear infoldings of cytoplasmic constituents.

Download Full-text

The Scanning Electron Microscopic Observation of the Vestibular Sensory Epithelia

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100062105 ◽

1969 ◽

Vol 27 ◽

pp. 40-41

Author(s):

D.J. Lim ◽

W.C. Lane

Keyword(s):

Semicircular Canals ◽

Electron Microscopic Observation ◽

Gravitational Acceleration ◽

Electron Microscopic ◽

Sensory Epithelia ◽

Scanning Electron Microscopic ◽

Vestibular Sensory Epithelia ◽

And Function ◽

Sand Piles ◽

Active Investigation

The morphology and function of the vestibular sensory organs has been extensively studied during the last decade with the advent of electron microscopy and electrophysiology. The opening of the space age also accelerated active investigation in this area, since this organ is responsible for the sensation of balance and of linear, angular and gravitational acceleration.The vestibular sense organs are formed by the saccule, utricle and three ampullae of the semicircular canals. The maculae (sacculi and utriculi) have otolithic membranes on the top of the sensory epithelia. The otolithic membrane is formed by a layer of thick gelatin and sand-piles of calcium carbonate crystals (Fig.l).

Download Full-text