Lec 33 Flashcards
oral phase
3 pairs of salivary glands
antibacterial actions
salivary glands are under —- control
autonomic–mostly parasympathetic
swallowing reflex
1- tongue push bolus back of mouth, trigger swallow reflex
2- breathing is inhibited
3- food moves downward into esophagus by peristaltic waves
gastric phase function
1- digestion
2- protection: protect itself with mucus and bicarbonate
3- storage: regulated release of chyme
stomach lumen ph
2
mucus and hco3- is secreted by
gastric mucus cells
pepsin is active between ph
1.8-3.5
pepsin start protein digestion by
breaking peptide bonds
absorbable bits of carbs
Monosaccharides
absorbable bits of protein
amino acid
absorbable bits of lipid
small fatty acids
protein in low ph is
denatured
gastric mucosa
1- mucous surface and neck cells: mucus and bicarbonate
2- parietal cells: HCl
3- chief cells: pepsin and gastric lipase
mucus function
physical barrier lumen and epithelium
bicarbonate function
buffer gastric acid
prevent damage to epithelium
HCl function
activate pepsin
kill bacteria
small intestine functions
1- secretion
2- digestion
3- absorption
small intestine secretion
1-epithelial cell: mucus, digestive enzymes(brush border)
2- pancreas: HCO3-,digestive enzyme
3- liver and gallbladder: bile
wall of small intestine
1- entrocytes:nutrient absorption
2- epithelial cells: secrete ion, water
3- goblet cell: secrete mucus
4- capillaries: transport absorbed nutrients
5- lacteals:transport fat via lymph system
in small intestine —- will divide to replace damaged cell
stem cell
exocrine pancreas
acinar + duct cells
acinar cells secrete
digestive enzyme
some inactive
some active: proteases,amylases,lipase
duct cell
secrete NaHCO3: neutralize acidic chyme
biliary secretion
amphypatic
non-enzymatic
Solution of bile salt, bile, cholesterol
produce by liver
diverted concentrated and stored in gallbladder
bile salt main role
digestion and absorption of fats
