Week 17 - GI Tract Flashcards
(26 cards)
What is mechanical digestion?
Physical breakdown of food (e.g., chewing, churning).
What is chemical digestion?
Enzymatic breakdown of food into absorbable molecules.
What regulates digestion in the GI tract?
Neural and hormonal mechanisms.
What is the role of the enteric nervous system in digestion?
Regulates local digestive activity via short reflexes.
What does parasympathetic stimulation do to GI activity?
Increases motility, secretions, and relaxes sphincters.
What is digestion in the GI tract?
Breakdown of food into absorbable components.
What is absorption in the GI tract?
Transfer of nutrients from the lumen to blood or lymph.
What is motility in the GI tract?
Movement of contents via muscular contractions.
What is secretion in the GI tract?
Release of substances like enzymes, acid, and mucus.
Which stomach cells secrete hydrochloric acid?
Parietal cells.
What is the function of HCl in the stomach?
Denatures proteins, activates pepsin, and kills microbes.
Which stomach cells secrete pepsinogen?
Chief cells.
What is the function of pepsin?
Breaks down proteins into peptides.
Which stomach cells secrete mucus?
Mucous cells.
What is the function of mucus in the stomach?
Protects the lining from acid and enzymes.
Which stomach cells release gastrin?
G cells.
What is the function of gastrin?
Stimulates acid secretion and gastric motility.
What begins during the cephalic phase of digestion?
Saliva and gastric secretions triggered by food cues.
What triggers the gastric phase of digestion?
Food entering the stomach and stomach distension.
What begins the intestinal phase of digestion?
Chyme entering the duodenum.
Which enzyme begins carbohydrate digestion in the mouth?
Salivary amylase.
What is the substrate for pepsin?
Proteins.
What is the substrate for lipase?
Triglycerides.
What is the substrate for brush border enzymes?
Peptides and disaccharides.
