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Lab 2 Epithelial Tissue: Index - 1)Introduction - 2)Simple Squamous - 3)Simple Cuboidal - 4)Simple Columnar - 5)PsuedoStratified - 6)Transitional - 7)Stratified Squamous - 8)Stratified Columnar - 9)Stratified Cuboidal - 10) Trachea and Esophogus Comparison - 12) Practical |
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PSEUDOSTRATIFIED COLUMNAR EPITHELIUM Essentially the same as simple columnar epithelium, but nuclei are not all at the same level. |
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1. lining of the trachea Things to identify: tall principal cell / basal cell / goblet cell # 150 - Trachea, rabbit, h&e, 1.5 mm # 6 - Pseudostratified Columnar Epithelium, trachea |
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In Slide 150, a plastic-embedded thin section, observe the features of the lining epithelium, its basement membrane, and the goblet cells interspersed in the epithelium. Remember that in pseudostratified epithelia, all cells reach the basement membrane, but not all reach the apical surface. Note the thickness of the basement membrane that is found in the trachea. In slide #6, find good examples of simple squamous epithelium lining the lymphatic capillaries. References: Gartner, p. 32, Fig. 4 p. 243, Fig. 3 Ross, p. 87, Fig. 4 p. 229, Fig. 3 p. 553, Fig. 2 Wheater, p. 224, Fig. 12.5 DiFiore, p. 15, Fig. 1-6
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This is a close up shot of the mucosa of the trachea. Notice how it looks as if there are several layers of cells present. However, that is not the case. All the cells are in contact with the basement membrane. What creates this psuedo stratified look are the basilar cells indicatied by the blue arrow. They do not extend as far as the tall principle cells indicated by the red border. The green arrow is pointing out a familiar goblet cell What is the yellow arrows pointing to? Is it microvilli no. HINT: If you can actally see the spaces between the processes sticking out of the cells they are most likely cilia. And that is exactly what they are here. |
Epithelium of Trachea Yellow Arrows - Cilia of epithelial cells Blue Arrow - basal cell Red Border - tall principle cell Green Arrow - Goblet cell |
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2. lining of part of the male reproductive ducts Things to identify: tall principal cell / basal cell / stereocilia # 167 - Epididymis, h&e |
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The lining of the epididymis is another example of pseudostratified epithelium. There are tall principal cells and small basal cells in this pseudostratified tissue. This lining epithelium has surface modifications known as stereocilia (long branched microvilli). Note the sperm. References: Gartner, p. 371, Fig. 4 Ross, p. 87, Fig. 5 p. 373, Fig. 1 Wheater, p. 79, Fig. 5.5 DiFiore, p. 283, Fig. 18.6 p. 331, Fig. 18.12b |
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The red bracket is outlining a tall principle cell that extends the length of the epithelium while the white lines are outling the basal cells which are locate at the bottom. Remember all cells in a psuedostratified epithelium touch the basement membrane. White lines - Basal cells Blue arrows - Cilia Red Bracket - Tall principle cell |
Epithelium of Epididymus |
