Term
| What type of epithelium line the oral cavity? |
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Definition
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Term
| What are the 4 Papillae of the tongue |
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Definition
1. Filiform - no taste buds, increase friction between tongue and food
2. Fungiform
3. Foliate
4. Circumvallate - Associated with Ebner's glands |
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Term
| What do Ebner's glands do? |
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Definition
| Secrete substance that helps dissolve food particles so they can access the taste buds |
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Term
| What are the 4 components of a taste bud? |
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Definition
1. Taste cell
2. Supporting cell
3. Basal cell - serve as stem cells for new cells
4. Nerve fiber - Necessary to make new cells
Note: these exist on fungiform, circumvallate, and foliate papillae, not filiform, which lack taste buds |
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Term
| What are the 3 salivary glands? |
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Definition
1. Parotid
2. Submandibular
3. Sublingual |
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Term
| What are the two general classes of glands? |
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Definition
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Term
| What type of cells secrete in acinar glands? What type of cells contract to push secretions out? |
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Definition
1. Acinar cells secrete
2. Myoepithelial cells contract to push secretions out
Note: Mixed acinus glands also have demilume cells behind the acinar cells that secrete into the lumen and mix with the secretions of the acinar cells |
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Term
| What enzymes are in saliva and what purpose do they serve? |
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Definition
1. Lysozyme - breakdown bacterial cell walls (protective function)
2. Amylase - Begins breaking down starches and complex carbs
3. Lipase - begins breakdown of lipids and fats |
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Term
| What are the major layers of the GI tract? |
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Definition
1. Mucosal - consists of epithelial, lamina propria (connective tissue), and muscularis mucosae (smooth muscle) layers (has most specialization between organs)
2. Submucosal layer - glands, nerves in this layer referred to as Meissner's plexus
3. Mascularis externa - Two muscles layers, inner one is circular and outer one is longitudinal
4. Serosa (adventitia) - connective tissue layer |
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Term
| What are the major anatomical parts of the stomach? |
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Definition
1. Cardia - entrance point from esophagus
2. Fundus - part of stomach above the cardia
3. Body - part of stomach below cardia
4. Pylorus - exit of stomach |
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Term
| What extra muscle layer is present in the stomach and what is its role? |
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Definition
Oblique muscle layer
Churns food in the presence of gastic juice to make chyme |
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Term
| Describe the major anatomical regions of tubular glands and the cells within them |
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Definition
1. Gastric pit - entrance point from the lumen, lined by surface mucosal cells (secrete a protective mucous to line the stomach)
2. Neck - narrower then pit, parietal cells, mucous neck cells, and APUD cells
3. Base - End of gland, chief cells and APUD cells |
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Term
| What do parietal cells secrete? |
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Definition
Hydrochloric acid and "intrinsic factor" (whatever the hell that is)
Note: These cells have an intracellular canaliculus (invagination lined with microvilli) that is important in HCl secretion |
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Term
| What do chief cells secrete? |
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Definition
| Proteins, and pepsinogen (inactive form of pepsin, becomes active at low pH) |
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Term
| What do APUD cells secrete? |
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Definition
| peptide hormones into the bloodstream, not the lumen |
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Term
| What type of stomach cell are G cells and where are they found? |
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Definition
| APUD cells found in the pyloric area. The presence of food stimulates them to secrete gastrin, which promotes secretion of pepsin and acid |
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Term
| Describe the process that entails the release of HCl from Parietal cells |
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Definition
1. Food presence stimulates gastrin release
2. Gastrin binds to prietal cell receptor
3. ER fuses with canaliculus (increases surface area)
4. H+/K+ ATPase pumps 0.15 HCl out of cell
Note: Bicarbonate is also pumped into the bloodstream during this process which can mix with the mucosal layer of the stomach and buffer it against the low pH |
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Term
| What sphincter separates the stomach from the small intestine? |
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Definition
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Term
| What types of cells distinguish the line between the stomach and the small intestine? |
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Definition
Stomach - stratified squamous epithelium
Small intestine - microvilli are present on the epithelium |
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Term
| What is a plica and where is it present? |
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Definition
Projection of the epithelial wall into the lumen lined with villi
Present in the small intestine |
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Term
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Definition
| Lymphatic capillaries that extend up into the villi and eventually empty into the thoracic duct |
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Term
| What role does smooth muscle play in the villi? |
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Definition
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Term
| What are the Crypts of Leiberkuhn? |
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Definition
| Tubular glands of the intestine |
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Term
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Definition
| Mucous secreting cells packed full of carb granules |
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Term
| Where are paneth cells located? What is their purpose? |
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Definition
They are located in the base of crypts.
They secrete proteins, mostly lysozyme. |
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Term
| What is the role of enterocyte cells and where are they found? |
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Definition
Absorption. Small intestine.
They make a brush border with thousands of microvilli to aid in absorption. |
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Term
| What are the 3 section of the small intestine and what features distinguish them? |
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Definition
1. Duodenum - Have Brunner's glands (in mucosal layer) to help neutralize pH and protect cells
2. Jejunem - Very prominent plicae
3. Ileum - Peyer's patches are clusters of lymph nodes |
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Term
| What are the two major functions of the large intestine? |
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Definition
1. Absorb water
2. Lubricate passage of feces |
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Term
| What is the transition point between the small and large intestine? |
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Definition
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Term
| What feature most prominently distinguishes the small from large intestine? |
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Definition
| There are NO villi in the large intestine (also there is a thickening of the muscle layer, but the villi are more obvious) |
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Term
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Definition
| Bulges in the muscle layer that become more prominent and eventually continuous as you travel down the large intestine |
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