1. Author(s): Michael Hortsch, Ph.D., 2010 License: Unless otherwise noted, this material is made available under the terms of the Creative Commons Attribution – Non-Commercial 3.0 License: http://creativecommons.org/licenses/by-nc/3.0/ We have reviewed this material in accordance with U.S. Copyright Law and have tried to maximize your ability to use, share, and adapt it. The attribution key found at the end of the module provides information about how you may share and adapt this material. Copyright holders of content included in this material should contact open.michigan@umich.edu with any questions, corrections, or clarification regarding the use of content. For more information about how to cite these materials visit http://open.umich.edu/education/about/terms-of-use. Any medical information in this material is intended to inform and educate and is not a tool for self-diagnosis or a replacement for medical evaluation, advice, diagnosis or treatment by a healthcare professional. Please speak to your physician if you have questions about your medical condition. Viewer discretion is advised: Some medical content is graphic and may not be suitable for all viewers.

2. Histology of the Ear- Second Look Michael Hortsch, Ph.D. Department of Cell and Developmental Biology University of Michigan © 2010 Michael Hortsch

3. Name the three main spaces of the bony labyrinth. Indicate their positions in the micrograph on the left.

4. Name the three main spaces of the membranous labyrinth and try to indicate their positions in the micrograph on the left. (The parts of the bony labyrinth are indicated by the pointed lines. The second part of this task is rather difficult as the semicircular duct and the saccule are partially collapsed.) Endolymphatic duct Collapsed membranes

5. Where can they be found in the inner ear and what is their physiological function ? Also describe their chemical composition ? Identify the structures shown in the scanning electron micrograph on the left. Image courtesy of Y. Raphael and L.A. Beyer, University of Michigan

6. Identify the structure in the micrograph on the right, which is encircled by the red line. In which part of the membranous labyrinth would you expect to find it ? What type of sensory information is this structure able to perceive ?

7. Identify the structure shown in the micrograph on the left. In which part of the membranous labyrinth would you expect to find it ? What type of sensory information is this structure able to perceive ?

8. Identify the spaces and structures indicated by the lines and arrows.

9. Which two scalas are connected/continuous at the helicotrema ? Scala vestibuli Scala tympani Scala media

10. Scala vestibuli Scala tympani Scala media Are low or high frequency sounds perceived at the helicotrema ?

11. Identify the spaces, structures and cells indicated by the lines and arrows. If the arrows point to cell nuclei or cell bodies, identify the cells.

12. Identify the area that is marked by the dotted line in the magnified image on the left. Name the most important function of the cells in the stria vascularis. Is endolymph closer in its composition to intra- or extracellular fluid ?

13. Which of the three spaces that are labeled with A, B and C is/are filled with endolymph ? Name the space(s). A B C

14. Which of the six spaces that are labeled with A, B, C, D, E and F is/are filled with endolymph ? A BC D E F

15. This scanning electron micrograph shows four rows of hair cells (A, B, C and D). Identify them correctly. Which row(s) is/are primarily responsible for the perception of sound and which have a more modulating function ? A C B D Image courtesy of Y. Raphael and L.A. Beyer, University of Michigan

16. Slide 3:Michigan Histology EAR-2_HISTO_40X.svs bony labyrinth 5% Slide 4:Michigan Histology EAR-2_HISTO_40X.svs bony labyrinth 5% Slide 5:Image courtesy of Y. Raphael and L.A. Beyer Slide 6:Michigan Histology EAR-3_HISTO_40X.svs saccule macula 33% Slide 7:Michigan Histology EAR-4_HISTO_40X.svs Crista ampularis 25% Slide 8:Michigan Histology 080a_HISTO_40X.svs Cochlear duct 33% Slide 9:Michigan Histology EAR-2_HISTO_40X.svs 29% Slide 10:Michigan Histology EAR-2_HISTO_40X.svs 29% Slide 11:Michigan Histology EAR-1_HISTO_40X.svs Organ of Corti 77% Slide 12:Michigan Histology EAR-3_HISTO_40X.svs cochlear duct stria vascularis 35% and 88% Slide 13:Michigan Histology EAR-1_HISTO_40X.svs Cochlear duct 30% Slide 14:Michigan Histology EAR-1_HISTO_40X.svs Organ of Corti 77% Slide 15:Image courtesy of Y. Raphael and L.A. Beyer Attributions by Slide

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