Histo Stuff Flashcards
Name three major functional categories of intercellular junctions and the major role served by each.
tight junctions, adherent junctions along with
desmosomes, and gap junctions.
What type of epithelial junction is associated with the basal lamina? What is its function?
Hemidesmosomes join basal epithelial cells to the basal lamina by linking the cytoskeleton to that extracellular layer.
Why does not every region of the vascular endothelial lining show cell nuclei?
Most of the endothelial cell nuclei are located outside the plane of the section.
What are the structural differences between the apical and basal sides of cuboidal epithelial cells?
Apical ends of cuboidal and columnar cells may have cilia, microvilli, or less-structured projections;
their basal ends are always bound to the basal lamina with hemidesmosomes.
Draw several columnar epithelial cells, showing the basement membrane, nuclei, and
the apical ends with microvilli and glycocalyx.
How do cilia and microvilli differ structurally and functionally? To which of these are stereocilia most similar?
Cilia are larger structures, each with a well-organized axoneme of microtubules at its core; microvilli each contain various numbers of microfilaments.
What is meant by the term “polarity” as applied to epithelial cells?
In epithelial cells “polarity” refers to a cell’s basal end (on the basement membrane andin columnar cells typically containing the nucleus) and its apical end on the oppositeside.
What is the function(s) served by pseudostratified columnar ciliated epithelium?
Protection, secretion; cilia-mediated transport of particles trapped in mucus out of the air passages.
What functions are served by stratified squamous keratinized epithelium?
Unlike the apical cells of nonkeratinized stratified squamous epithelia, the cells of keratinized epithelia provide both more robust protection against damage from abrasion and from desiccation (water loss from underlying tissues).
What portion of a simple and compound gland is branched or not branched,
respectively?
The ducts draining a gland’s secretory portions determine whether a gland is “simple” or “branched.”
What parts of a gland do the terms “tubular” and “acinar” refer to?
“Tubular” and “acinar” (rounded) refer to the general shape of the group of cells comprising a gland’s secretory portions.
Why do serous cells typically stain much better than mucous cells?
Unlike mucous cells which contain mainly granules of mucopolysaccharides (similar to glycosaminoglycans) which react poorly with both hematoxylin and eosin, serous cells are rich in rER (basophilic) and acidophilic protein-filled granules.
Which mode of secretion occurs most commonly among glands in humans?
Merocrine secretion is the most common mode of glandular secretion.
