Histology- GI tract
Terms
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- What are APUD's?
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Amine Precursor Uptake and Decarboxylation cells.
"Enteroendocrine" cells: produce and secrete hormones
- Where can you find taste buds?
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1) Fungiform, Circumvallate papillae
2) Palate
3) Palatoglossal Arch
4) Palatopharyngeal Arch
5) Pharynx and Larynx - What is a lacteal?
- It is a blind ended lymphatic within the villi of the small intestine.
- What are the von Ebner glands?
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These are serous glands that open into the trenches around the cicumvallate papillae.
- What types of hormones do APUD's secrete?
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1) Gastrin
2) Secretin
3) Cholecystokinin
4) Somatostatin - Why are filiform papillae different?
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1) Smallest and most numerous
2) Provide tongue with rough surface for food manipulation
3) Cone like - Describe the intestinal glands of the small intestine:
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1) Simple
2) Straight
3) Tubular
4) Penetrate to the level of the Muscularis mucosa - What are the fungiform papillae?
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1) Occur in anterior 2/3
2) Loners and evenly spaced between filiform papillae
3) CT core is highly vascularized
4) Epithelium slightly thinner than the rest of tongue - How can you tell the pyloric region of the stomach?
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Villi: NO
Glands: Short Coiled
Parietal and chief cells: NO
Pits: Long - What types of muscles are in the tongue?
- Skeletal musc. arranged more or less perpendicular to each other.
- How is the Small intestine divided?
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1) Duodenum (Brunner's glands)
2) Jejunum
3) Ileum - In general, what are the ingredients of the lingual papillae?
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1) connective tissue core
2) Stratified squamous epithelium
- What are Chief Cells?
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1) Lower half of gastric gland
2) Pepsinogen (becomes active as pH goes down) - How is the dorsal surface of the tongue is divided?
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It is divided by the sulcus terminalis
1) anterior 2/3 (Oral part)
2) posterior 1/3 (Pharyngeal part) - Describe the changes in villi through the course of the small intestine:
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1) Duodenum: Short, leaf shaped plates
2) Jejunum: Club shaped
3) Ileum: Finger shaped and tall
They all contain rich supply of vessels, lacteals, and SM - Describe the epithelium of the DORSAL side of the tongue
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Epithelium: stratified squamous
CT: Very dense and connects the epithelium to the underlying muscle - What are the cells that you will find in the gastric pits of the Body and Fundus?
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1) Parietal
2) Chief
3) Mucous neck cells
4) Enterochrimaffin cells
5) APUD's - What can you find on the oral part of the tongue?
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Large number of papillae
1) Filiform
2) Fungiform
3) Circumvilate
4) Foliate - What do you find in the Lamina propria of the intestine?
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1) CT
2) Vascular elements
3) diffuse and nodular LYMPHOID TISSUE
4) Muscularis mucosa (inner: circ :: outer: long) - Where to the circumvallate pap. appear?
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1) In depressions of the surface of the tongue
2) Surrounded by trench formed by in folded epi
- How many layers does the muscularic mucosa have in the stomach?
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2 to 3 layers of smooth muscle that creeps up between glands
- What are the circumvallate papillae?
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1) Largest least numerous
2) 8-12 of them
3) Taste buds line the walls
4) Glands of Von Ebner open into trenches - What types of cells do you find in the mucosa of the small intestine?
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1) Simple Columnar
2) Goblet Cells-> Mucous
3) Paneth Cells-> bottom of crypts
4) Argentaffin and APUD cells (basal section of glands)
5) Lamina Propria - What are Argentaffin Cells?
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1) Enterochromaffin cells
2) Derived from neural crest cells
3) Basal portions of the glands
- How does the small intestine increase its surface area? (6)
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1) Villi
2) Extreme length
3) Plicae Circulares
4) Intestinal Glands
5) Microvilli on apical surface of absorptive cells
6) Glycocalyx - How can you determine the Body and Fundus?
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Villi: NO
Glands: Coiled
Parietal and Chief cells: YES
- What are brunner's glands?
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Submucosal duodenal glands that produce an ALKALINE secretion to protect wall from low pH.
Sets optimal pH for pancreatic enzymes - What are some of the gross anatomical features of the stomach?
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1) Rugae (longitudinal folds that change in distention)
2) Cardiac Region
3) Fundic/Body region
4) Pyloric region - What makes the duodenum different?
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Villi: YES
Submusocal glands: YES (brunner's) - Esophagus: Muscle Layer
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1) Two layers of Muscle
2) Top 1/3 is wrapped in skeletal muscle
3) Middle is combination
4) Bottom 1/3 is all smooth muscle - What does the inner layer of the Muscularis mucosa of the small intestine do?
- Sends fibers into the villi that contract every 10 seconds
- How can you tell the cardiac region?
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Villi: NO
Glands: Coiled and long
Parietal and Chief cells: NO
Pits: Short
- How can you identify the Ileum?
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Villi: YES (Farther apart)
Submucosal Glands: NO
Plicae Circulares: YES (but less)
Peyers Patches: YES
Goblet cells: Increase - What are parietal cells?
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1) HCL
2) Vit B12 intrinsic factor
3) Middle portion of gastric glands with mucous neck cells
4) Have Mitochondria for ATP pumps
5) Triangular in Shape - How can you tell the Large Intestine?
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Villi: NO
Goblet cells: YES!!! (Lots)
Mucosal glands: Tubular
Lymphoid Tissue: Nodules
Outer layer: Tenia Coli - What types of cells do you find in Gastric Pits?
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1) Stem Cells
2) Mucous Neck Cells
3) Parietal cells
4) Chief cells
5) Enteroendocrine cells - How can you identify the Jejunum?
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Villi: YES
Submucosal Glands: NO
Plicae Circulares: YES
Peyers Patches: NO
Goblet cells: Some
- Esophagus: Outer Layer
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1) Thoracic portion is covered in adventitia (CT)
2) Sub-diaphragm is wrapped in serosa - What is the muscularis mucosa like in the esophagus?
- VERY THICK (Generally m.m. is thin)
- Describe the mucosa of the esophagus
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1) Lined with stratified squamous epithelium
2) Lamina propria
3) relatively thick muscularis mucosa
4) Cardiac glands that secrete mucous near the stomach - What do you find in the Submucosa?
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1) Layer of CT with blood and lymph vessels
2) Meissner's plexus for contraction
3) Submucosal Glands (Esophagus and duodenum)
- Esophagus : Submucosal layer
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1) "Esophageal" glands
2) Relatively thick fibroelastic layer that stretches as you swallow - What is in the Lamina Propria?
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1) Areolar CT
2) Blood vessels
3) Nerves
4) Smooth muscle
5) Glands - What are mucous neck cells?
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1) Mucous
2) Occur singly or in clusters between parietal cells
3) Upper half of Gastric glands - How does a taste bud work?
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1) Pieces of food are sampled in the trenches
2) Sensory cells extend microvilli into taste pore.
3) There are receptors on the microvilli with different taste modalities - Describe the Muscle layer of the general GI.
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1) relatively thick
2) Composed of SM into 2 layers (inner: circular :: outer: Longitudinal)
3) Auerbach's plexus between the layers of muscle - Describe the mucosa of the gut
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1) Faces the lumen
2) Epithelial lining
3) Lamina Propria
4) Muscularis mucosa - Segmentalize the esophagus:
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1) First third contains Skeletal muscle
2) Mixture
3) Smooth muscle - What is a serosa?
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The combination of adventitia (CT) and mesothelium (s.s. epi)
Contains: blood vessels, lymphatics, nerves, and adipose tissue - Where do you find a serosa?
- The outer most layer of the gut. All over the gut, except in the eophagus
- What is the general plan of the Digestive tract?
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1) Mucosa
2) Submucosa
3) Muscle Layer
4) Serosa or adventitia