Digestion (Test 3) Flashcards
What are the 4 basic digestive processes?
- Digestion
- Motility
- Secretion
- Absorption
What is digestion?
- The mechanical and chemical breakdown of food
What is motility?
- The movement of material along the digestive tract
- What is secretion?
- The release of enzymes into the digestive tract
What is absorption?
- Active or passive transfer of substances from the lumen of the digestive tract to extracellular fluid
What are the three digestive organs that act to provide the correct chemical environment for food breakdown and absorption?
- Liver
- Pancreas
- Gallbladder
Where does muscularis interna (segmentation) mostly occur?
- Small intestine
Where does muscularis externa (peristalsis) mostly occur?
- Esophagus
- Stomach
- Large intestine
What are the digestive system organs?
- Mouth
- Salivary glands
- Pharynx
- Esophagus
- Liver
- Gallbladder
- Stomach
- Pancreas
- Small intestine
- Large intestine
- Rectum
- Anus
What does the mouth do?
- Breaks up food particles
What do the salivary glands do?
- Saliva moistens and lubricates food
- Amylase digests polysaccharides
- Secretes amylase, lipase, and saliva
What does the pharynx do?
- Swallows
What does the esophagus do?
- Transports food
What does the liver do?
- Breaks down and builds up many bio molecules
- Stores vitamins and iron
- Destroys old blood cells
- Destroys poisons
- Bile aids in digestion
What does the gallbladder do?
- Stores and concentrates bile
What does the stomach do?
- Stores and churns food
- Secretes pepsin and HCl
- Mucus protects the stomach wall
- Limited absorption
What does the pancreas do?
- Hormones regulate blood glucose levels
- Bicarbonates neutralize stomach acid
- Secrete trypsin, chymotrypsin, amylase, and lipase
What does pepsin, trypsin and chymotrypsin digest?
- Proteins
What does amylase digest?
- Polysaccharides
What does lipase digest?
- Lipids
What does HCl do?
- Activates enzymes
- Breaks up food
- Kill germs
What does the small intestine do?
- Completes digestion
- Contains villi
- Mucus protects gut wall
- Absorbs nutrients, mostly water
- Secretes peptidase, sucrase, and amylase
What does the large intestine do?
- Reabsorbs some water and ions
- Forms and stores feces
- What does the rectum do?
- Stores and expels feces
What does the anus do?
- Opening for feces elimination
What are the 3 segments of the small intestine
- Duodenum
- Jejunum
- Ileum
What sphincter separates the stomach and the small intestine?
- Pyloric sphincter
What factors cause gastric emptying to decrease?
- Acid
- Duodenum distension
- Enterogastrones (CCK, GIP, and secretin (decreased pH) feedback on chief and parietal cells)
What factors cause gastric emptying to increase?
- Large chyme volume in the stomach
- High protein content in chyme
- Gastrin
When is CCK released?
- High levels of proteins in the duodenum
Which cells within the pancreas release CCK and bicarbonate?
- Acinar cells
Where does carb breakdown begin?
- In the mouth by salivary amylase
Where does protein breakdown begin?
- In the stomac by pepsin
Where does nucleic acid and fat breakdown begin?
- Small intestine
Starch/glycogen gets broken down to what?
- Disaccharides
What converts inactive trypsinogen to active trypsin?
- Enteropeptidase
Where do macromolecules travel after being absorbed?
- Liver
