Histology of the Human Ear I. External ear (Figure ... - Faculty.rmc.edu
Histology of the Human Ear I. External ear (Figure ... - Faculty.rmc.edu
Histology of the Human Ear I. External ear (Figure ... - Faculty.rmc.edu
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III. Inner <strong>Ear</strong> (<strong>Figure</strong> 25.1, 25.3, 25.7)<br />
A. Osseus Labyrinth<br />
1. cavity in temporal bone<br />
2. contains membranous labyrinth<br />
3. also contains perilymphatic fluid space between bone and membranous labyrinth which<br />
forms <strong>the</strong> vestibule and <strong>the</strong> outer channels <strong>of</strong> <strong>the</strong> cochlea (vestibular duct and tympanic<br />
duct)<br />
4. areas between bone and fluid spaces filled with loose FECT<br />
5. fluid spaces are lined with simple squamous epi<strong>the</strong>lium<br />
B. Membranous Labyrinth<br />
1. lined with simple squamous epi<strong>the</strong>lium in most areas<br />
2. lined with simple columnar epi<strong>the</strong>lium with "hair" cells in sensory areas<br />
3. lined with simple cuboidal or columnar epi<strong>the</strong>lium in fluid production/resorption areas<br />
4. epi<strong>the</strong>lium underlain by loose FECT in most areas<br />
C. Sensory Receptor Structures in <strong>the</strong> Inner <strong>Ear</strong> (<strong>Figure</strong> 25.8, 25.9)<br />
1. Common features <strong>of</strong> receptors<br />
a. Sensory receptors in all cases are "hair" cells.<br />
(1) "Hair" cells are columnar epi<strong>the</strong>lial cells in <strong>the</strong> wall <strong>of</strong> <strong>the</strong> membranous<br />
labyrinth.<br />
(2) "Hair" cells have an apical V-shaped array (viewed from <strong>the</strong> surface) <strong>of</strong><br />
microvilli.<br />
(3) "Hair" cells have ei<strong>the</strong>r a kinocilium (sensory cilium, found in hair cells in <strong>the</strong><br />
maculae and <strong>the</strong> ampullae) or <strong>the</strong> basal body <strong>of</strong> a kinocilium (in <strong>the</strong> hair cells <strong>of</strong><br />
<strong>the</strong> Organ <strong>of</strong> Corti in <strong>the</strong> cochlea) is located at <strong>the</strong> apex <strong>of</strong> <strong>the</strong> "V" shaped array<br />
<strong>of</strong> microvilli.<br />
b. The processes (microvillae) <strong>of</strong> <strong>the</strong> hair cells are embedded in gelatinous accessory<br />
structures which modify <strong>the</strong> stimuli (gravity, movement, sound) into mechanical<br />
motion <strong>of</strong> <strong>the</strong> hair cell processes.<br />
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