Digestion and Absorption Flashcards
what are the stages of digestion and absorption
mouth
oesophagus
stomach
intestines
digestion definition
breakdown the large molecules into small/simpler molecules
absorption definition
small molecules pass through cell membranes into the blood or lymph capillaries
refresher for enzymes
typically proteins
increase the speed of most chemical reactions that take place within cells, catalyst
vital for life
important for digestion and metabolism
cleavage
what is cleavage
splitting of a large complex molecule into smaller or simpler molecules
models that demonstrate enzyme action
lock and key
induced fit
lock and key model
both enzyme and substrate have a specific configuration and unique shape that fit together
induced fit model
the substrate induces the enzyme to adopt the form of the substrate
enzymes are flexible and favour geometric adoption for binding and catalysis of the substrate
digestion product of proteins
amino acids
digestion product of fats
fatty acids and glycerol
digestion product of carbohydrates
monosaccharides
monosaccharides
glucose
galactose
fructose
where does digestion and absorption take place
mouth
oesophagus
stomach
small intestine
large instestine
components of the GI tract
mouth
oesphagus
stomach
small intestine
large intestine
anus
accessory organs associated with the alimentary tract
salivary glands
liver
gall bladder
pancreas
another word for chewing
mastication
types of digestion in the mouth
mechanical
chemical
mechanical digestion in the mouth
3 main functions
reduces the size of ingested particles
mixes food with saliva, lubricating it and exposing the food to digestive enzymes
increasing the surface area of ingested material
increasing the surface area of ingested material
increases the rate it can be digested
chemical digestion in the mouth
salvia contains 2 enzymes with fat and carb targets
salivary amylase
lingual lipase
starch chemical digestion in the mouth
alpha amylase (ptyalin) cleaves internal alpha-1,4-glycosidic bonds present in starch
produces maltose, maltotriose and alpha limit dextrins
fat chemical digestion in the mouth
lingual lipase
plays role in hydrolysis of dietary lipids
ph of saliva
6.2-7.6
eliminates acids from food, drink and bacteria
clinical importance of salivary amylase
infants have low levels of pancreatic enzymes in the first year
pancreatic insufficiency e.g. cystic fibrosis