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Exam 2: Digestive System IV
Terms in this set (14)
Why and how does the duodenum signal the stomach?
1. Needs to regulate the amount of chyme going into it
-This is a positive feedback mechanism to increase digestion in the stomach and release chyme into the duodenum. There is also a negative feedback mechanism when there is no food left in the stomach.
-to tell the stomach to keep going and to tell it to stop..........
What signals are recognized by sensory cells in the intestines that also elicit a response to the stomach?
-Sensory cells that recognize bulk, changes in pH and chemicals
-Receptors that recognize stretch in the organ are called mechanoreceptors
-Chemoreceptors can sense changes in pH and enteroendocrine cells referred to as the "tastebuds" of the GI system recognize various breakdown products from ingested food
-these receptors regulate muscle contraction and cell secretion through parasympathetic neurons
What do CCK, GIP and secretin do to the function of the stomach?
-they inhibit the secretion of chief, parietal cells and inhibit peristalsis or movement of the stomach, this allows the stomach to relax and stop movement and secretion
-if there is nothing in the stomach, it tells the stomach to stop functioning to conserve energy in the system, decreases muscle contraction and lowers secretions of mucous, HCl and pepsinogen
Why are CCK, GIP, and secretin important to intestinal functions?
-CCK: talks to other organs to increase synthesis and secretions
-GIP: stimulates insulin release, makes duodenal glands more active to secrete more mucous that neutralizes chyme
-Secretin: stimulates release of water and bicarbonate to raise the pH in duodenum toward a neutral pH, helps regulate gastric motility so food is delivered slowly to the duodenum
Name several ways that absorption is maximized in the intestine.
-long length, increased folds such as the plicae to increase cell surface area
-peristalsis moves digested food over new areas
-segmentation: back and forth movement causes intestines to absorb nutrients from the same bolus of digesting food
Describe the structure and function of the basic cell types in the intestine.
-Paneth, goblet and mucous cells have product stored in vesicles in the top of the cytoplasm and the RER and Golgi and the nucleus is in the base and it sends the contents of the vesicle into the lumen
-Columnar cell/enterocytes transport the basic building blocks of foods thru its apical membrane into the cytoplasm and thru the basal membrane into the underlying CT....
-Enteroendocrine cells secrete signaling molecules through the basal lamina to tell other cells what to do....
-stem cells: differentiates into other cells
Of the following, which phase does NOT describe the intestinal phase?..
a. intestinal capillaries
Glands that secrete an alkaline mucous to neutralize the acidic chyme originating from the stomach are located in the...
c. submucosa of the duodenum
Which of these enhance the ability of the small....
e. all of the above
Of the following, which process is used to absorb the nutrient cholesterol into cells in the small intestines...
What is the type of epithelium separating from capillaries in the lamina propria?...
a. simple columnar
Enteroendocrine cells secrete their product into
c. activation of duodenal glands
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