Actual Last DI Flashcards
polysaccharides given examples
starch and glycogen
proteins splitters
polypeptides being split by such as pepsin, trypsin, chymotrypsin
effectors in gastrointeestinal regulation
smooth muscle contraction and epithelial cells
short reflexes
stimuli-receptor-pelxus-effector-response
long reflexes
afferent-receptors to cns
efferent-autonomic motor (sympathetic and parasympathetic) - cns to plexus
cephalic phase to stomach
-parasympathetic to stomach in preparation for food coming
-response: increase acid secretion and stomach motility
salivary amylase best in?
slight acidic enviornment (conditons from mouth to fundus of stomach)
lingual lipase best in?
highly acidic environment (condtitions from body to antrum of stomach)
limited absorption in mouth (can be absorbed a bit)
some vitamins and mineral, electrolytes, alcohol, drugs
goals of masticatin
physical digestion (expose more SA) - motility (mix with enzymes in mouth is start of chemical digesiton) - forming bolus
deglutition muscles?
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mastication invoves?
skeletal muscles plus activity of tongue, lips, and cheeks
-combination of voluntary and involuntary masticaiton patterns and reflexes (rhythmic jaw movements)
first point of pharyngeal stage of deglutition
oral pharynx RECEPTORS send signal to swallowing centre that bolus is present, stop signal once bolus in esophagus
lower esophageal sphincter contracts after what?
esophageal stage of deglutiton
stomach - filling and storage intitially
-expands during meals to accomodate foods and liquid
-need to slow down GI tract motility (ingestion faster than digestion/absorption)
gastric motility
-mixing waves that are propulsive and retropulsive
-pacemaker cells in smooth muscle set basic wave rate that can be altered by neural and hormonal
-stronger motility in body and antrum, minimal in fundus
-breaks down bollus into chyme
gastric emptying
small amount of gastric juice (stomach chyme + secretions) per mixing wave moves into duodenum
gastric phase
food arrives in stomach - receptors detect increased distension - increased amino acids and peptides - decreased acidity
gastric phase neural
-increase HCl secretion
-increase gastric motility - greater gastric emptying
gasric phase hormonal
-increase HCl secretion
-increase gastric motility/relax pyloric sphincter - greater gastric emptying
-increase contraction lower esophageal sphincter - regurgitation prevention
intestinal phase
food arrives in duodenum - receptors detect increase acidity, fats, amino acids, distetnion
intestinal phase neural
enterogastric reflex
-short refelxes: enteric changes - directly effect stomach
-long reflexes: CNS (parasympathetic and sympathetic) changes - indirectly effect stomach
intestinal phase hormonal
CCK and secretin secretion and release into bloodstream/bind target cells in stomach
intestinal phase responses
-decreased gastric motility and increase contraction of pyloric sphincter - decreased gastric emptying
-trying to mach gastric emptying to small intestine digestion and absorption rates