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Histology-World!
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Histology Testbank: Gastrointestinal System 1a |
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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: b The small intestine is the primary site for absorption of nutrients. 2. Answer: e There are several features of the small intestine. The lymphatic capillary within a villus of the small intestine is a lacteal. Crypts of Lieberkuhn are the intestinal glands. The plica circulares is a projection with a core of submucosa. The plica circulares is also called the valve of Kerckring. Microvilli that are seen on the epithelial cells in the small intestine form the brush border or striated border. Villi are finger like projections of mucosa seen in the small intestine. 3. Answer: e The mucosa is the innermost layer of the GI tract. It consists of epithelium, lamina propria, and muscularis mucosa. The submucosa is connective tissue. Within it are lymphatic vessels and nerve plexuses. Meissner's plexus is located in the submucosa. The muscularis externa consists of thick layers of smooth muscle. It contains Auerbach's plexus. The outer layer of the GI tract is either an adventitia or serosa. The serosa consists of only a single layer of epithelial cells and underlying connective tissue. The adventitia is the outer layer of the GI tract when it is abutting another organ the posterior abdominal wall. 4. Answer: b The masticatory mucosa is located on the hard palate and gingiva. Lining mucosa is found on the underside of the tongue, lips, cheek, and soft palate. 5. Answer: e The masticatory mucosa is located on the hard palate and gingiva. The surface layer of masticatory mucosa is stratified squamous epithelium. (Remember, epithelium lines body cavities and covers body surfaces). The stratified squamous epithelium is keratinized. However, some regions of the masticatory mucosa are covered with non-keratinized stratified squamous epithelium and parakeratinized epithelium. Parakeratinized epithelium is similar to keratinized epithelium, except that in parakeratinized epithelium cell nuclei are present in the stratum corneum. 6. Answer: d The layers of the masticatory epithelium are similar to the layers of the epidermis. The stratum lucidum is not present in the masticatory epithelium. The epidermis is divided into five layers: stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, and stratum corneum. The stratum basale contains the dividing cells. This layer is also called the stratum germinativum. The stratum spinosum consists of a layer several cells deep. The cells have pointy or spiny processes on them. The cells in the stratum granulosum contain keratohyaline granules. The stratum lucidum is present only in thick skin. The stratum corneum is the outermost layer. The cells in this layer are essentially bags of keratin. They contain no nuclei or organelles. Histology hint from Sarah Bellham: My favorite mnemonic for remembering the layers of the skin: "Californian Ladies Give Superb Backrubs". 7. Answer: a The papillae on the tongue are located anteriorly to the sulcus terminalis. The tongue contains primarily three types of papillae: filiform papillae, circumvallate papillae and fungiform papillae. The filiform papillae are the smallest and most abundant. Filiform papillae are the only papillae on the tongue which do not contain taste buds. Circumvallate papillae large papillae arranged in a "V" shape. Fungiform papillae are mushroom shaped. Foliate papillae are not well developed in man and are seen on the edges of the tongue. Taste buds are found on cicumvallate, fungiform, and foliate papillae. 8. Answer: a The mucosa is the innermost layer of the GI tract. It consists of epithelium, lamina propria, and muscularis mucosa. The submucosa is connective tissue. Within it are lymphatic vessels and nerve plexuses. Meissner's plexus is located in the submucosa. The muscularis externa consists of thick layers of smooth muscle. It contains Auerbach's plexus. The outer layer of the GI tract is either an adventitia or serosa. The serosa consists of only a single layer of epithelial cells and underlying connective tissue. The adventitia is the outer layer of the GI tract when it is abutting another organ the posterior abdominal wall. 9. Answer: a There are several features of the small intestine. The lymphatic capillary within a villus of the small intestine is a lacteal. Crypts of Lieberkuhn are the intestinal glands. The plica circulares is a projection with a core of submucosa. The plica circulares is also called the valve of Kerckring. Microvilli that are seen on the epithelial cells in the small intestine form the brush border or striated border. Villi are finger like projections of mucosa seen in the small intestine. 10. Answer: d The papillae on the tongue are located anteriorly to the sulcus terminalis. The tongue contains primarily three types of papillae: filiform papillae, circumvallate papillae and fungiform papillae. The filiform papillae are the smallest and most abundant. Filiform papillae are the only papillae on the tongue which do not contain taste buds. Circumvallate papillae large papillae arranged in a "V" shape. Fungiform papillae are mushroom shaped. Foliate papillae are not well developed in man and are seen on the edges of the tongue. Taste buds are found on cicumvallate, fungiform, and foliate papillae. |
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