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Histology-World!
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Histology Testbank: Epithelium 3a |
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Instructions: For each histology question, pick the one best answer. This histology test bank is also useful for the histology questions on the USMLE (USMLE step 1). 1. Answer: d The epidermis is formed by stratified squamous epithelium. Epithelium lines body cavities and surfaces. Stratified squamous epithelium is "stratified" because it is more than one cell layer thick. "Squamous" refers to the fact that the surface cells of the stratified squamous layer are flat. This is important to note as the cells at the basal layer are cuboidal or even columnar. It is still classified as "squamous" based on the cells of the surface layer. 2. Answer: c The lining of the gastrointestinal tract is simple columnar epithelium. Epithelium lines body cavities and surfaces. Simple columnar epithelium is "simple" because it is one cell thick. "Columnar" cells are taller than they are wide and have an oval nucleus. 3. Answer: a The alveoli are formed by simple squamous epithelium. Epithelium lines body cavities and surfaces. Simple squamous epithelium is "simple" because it is one cell thick. "Squamous" refers to the fact that the cells are flat. 4. Answer: c Epithelium that is classified by the number of cell layers and the cell shape. Epithelium that is one cell thick is classified as simple. Epithelium that is more than one cell layer thick is classified as stratified. If the cells are flat, the epithelium is termed squamous. If the cells are as tall as they are wide, it is cuboidal. If the cells are taller than they are wide, the epithelium is classified as columnar. 5. Answer: b Epithelial tissue has cells that are very tightly packed together. There is always a free surface associated with epithelial tissue. If a tissue is composed of a conglomeration of cells in tightly packed together, but it does not have a free surface, the tissue is called epithelioid tissue. An example of epithelioid tissue is the parenchyma of the adrenal gland. Mesothelium is simple squamous epithelium that lines the abdominal cavity, the pericardial cavity, and the thoracic cavity. Endothelium is simple squamous epithelium that lines the vascular system. Transitional epithelium is seen in the urinary tract. Transitional epithelium has dome shaped cells on the apical surface. Pseudostratified epithelium is a type of epithelium that has cells which all touch the basement membrane. Pseudostratified epithelium is only one cell layer thick. Pseudostratified epithelium appears stratified, but it is not really stratified. Thus the name. The prefix "pseudo" means false, such as pseudonym or pseudo-science. 6. Answer: d Pseudostratified epithelium is a type of epithelium that has cells which all touch the basement membrane. Pseudostratified epithelium is only one cell layer thick. Pseudostratified epithelium appears stratified, but it is not really stratified. Thus the name. The other type of epithelium where all cells touch the basement membrane and are only one layer thick is the entire class of all of the simple epithelium. Note from Sarah Bellham: The prefix "pseudo" is derived from the Greek word and means false, counterfeit or untrue; examples of its usage include pseudonym or pseudo-science. 7. Answer: b Serosa lines the peritoneal cavity, pericardial cavity and pleural cavity. Mucosa lines the alimentary canal, genitourinary tract and respiratory tract. 8. Answer: b A simple gland has an unbranched duct. A compound gland has a branched duct. If the secretory portion of a gland is tube shaped, it is called "tubular". If the secretory portion of a gland is flask shaped, it is called "alveolar" or "acinar". If the secretory portion of a gland is a tube shaped but at the terminus is flask shaped, it is called "tubuloalveolar". 9. Answer: a Microvilli are the finger like projections seen on the surface of some cells. The appearance of microvilli form what is also called the brush border or striated border. Stereocilia are very long microvilli. Stereocilia are seen in the epididymis and the hair cells of the ear. Cilia is the hair like surface modification seen on some epithelia. Cilia are made of microtubules. Keratinization is seen in the epidermis. Cells in the stratum corneum are essentially just bags of keratin. 10. Answer: c Microvilli are the finger like projections seen on the surface of some cells. The appearance of microvilli form what is also called the brush border or striated border. Stereocilia are very long microvilli. Stereocilia are seen in the epididymis and the hair cells of the ear. Cilia is the hair like surface modification seen on some epithelia. Cilia are made of microtubules. Keratinization is seen in the epidermis. Cells in the stratum corneum are essentially just bags of keratin. |
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