lab 12: gastrointestinal system

why doesnt the stomach normally digest itself

the stomach does not digest itself because of the secretion of mucus from the gastric glands

mucus protects the lining of the stomach from acidic contents of the stomach lumen

microvilli of intestinal epithelial cells "the brush border"

describe the structural adaptations of the small intestine that help increase the rate at which the products of digestions can be absorbed

plicae: folds in the wall of the digestive tract

villi: folds in the epithelium

microvilli: folds in the cell membrane of the intestinal cells

ALL INCREASE SURFACE AREA

acinar cells and islets of langerhans

liver lobule

describe several functions of the liver and its anatomical connection to the alimentary canal

production of bile

storage of fat [triglycerides]

storage of carbs [glycogen]

conjugation of toxins to water-soluble molecules

bile stored in gallbladder and delivered to small intestine for emulsification of fat

describe the sources of digestive enzymes along the alimentary canal

salivary glands: amylase, lipase

gastric glands: pepsin

intestinal epithelium: brush border enzymes

pancreas: pancreatic enzymes

digestion of carbohydrates [starch]

digestion of protein [egg albumin]

compare the effects of HCl on protein digestion by pepsin vs the effects of HCl on starch digestion by salivary amylase

a low pH environment is essential to the function of pepsin but it prevents the function of salivary amylase

digestion of fat [cream]

how does fat digestion affect the pH of fluids in the lumen of the alimentary canal?

fat digestion results in the formation of fatty acids and therefore lowers the pH of the lumen of the alimentary canal