Flashcards in Digestive System Deck (32):
Occurs within the cell, often membrane bound vesicles
Occurs outside of the cell, within lumen/tract
Outline the pathway of food starting from oral cavity.
Oral cavity --> Pharynx --> Esophagus --> Stomach --> Small intestine --> Large intestine -- Anus
What type of digestion occurs in the mouth?
-Mechanical (mastication) and chemical (salivary amylase)
-Breaks starch into maltose (disacc)
-Rhythmic waves of involuntary muscular contractions
What separate the stomach and esophagus?
-Lower esophageal (cardiac) sphincter
Compare the relative pressure of the thoracic and abdominal cavities
-Thoracic cavity (where body of esophagus is) negatively pressured relative to environment on inhalation
-Abdominal cavity (+) pressure
Gastroesphageal reflux disease (GERD)
-Results from pressure gradients
-Reflux of gastric material into esophagus
What are chief cells?
-In gastric glands
What are parietal cells?
-In gastric glands
-Synthesize/release HCl and intrinsic factor (absorb vitamin B12)
What is the role of HCl?
-Converts pepsinogen to pepsin
What kind of digestion is in stomach?
-Mechanical (churning) and Chemical
Where does chyme pass into?
-Duodenum through pyloric sphincter
What lines the stomach walls?
-Gastric mucosa secreted by mucous cells
Where does chemical digestion finish?
What are the sections of the small intestine?
-Duodenum, Jejunum, Ileum
What do villi consist of?
-Capillaries and lacteals
Where do large fatty acids and glycerol go from the small intestine?
-Pass to lacteals then moved to liver where they're converted to tryglycerides
Which nutrients are actively absorbed?
-Amino acids and glucose
Where does most digestion in small intestines occur?
What does intestinal mucosa secrete?
Where and what is the function of gastrin?
-Produced by G cells in duodenum
-Stimulate histamine and pepsinogen secretion
-Stimulate parietal cells
Where and what is the function of intrinsic?
-Secreted by parietal cells
-Facilitate absorption of vitamin B12
-Produced by I cells of duodenal/jejunal mucosa
-Stimulate panreatic snzyme and somatostatin secretion
-Stimulate gallbladder contraction
-Synthesized by S cells of upper intestine
-Stimulate secretion of bicarbonate-containing substances from pancreas
-Inhibit gastric emptying and gastric acid production
-Produced by liver and stored in gallbladder
-Release to small intestine to emulsify fats
What is the purpose of emulsifying fats?
-Increase surface area for lipases
What are functions of the liver?
-Convert ammonia to urea
What does the pancreas produce?
-Amylase, trypsin, lipase
-Secrete bicarbonate containing substances
-Absorb salt and any water not absorbed by small intestine