GI 6: Digestion & Absorption of Proteins and Carbohydrates Flashcards
what are the 4 digestive processes?
- motility
- digestion
- secretion
- absorption
what must happen to macronutrients before they can be absorbed?
must be digested
t/f sometimes 2-3 amino acid peptides can be absorbed
true
triglycerides are broken down into ___ and __
glycerol and fatty acids
t/f monoglycerides can be absorbed
true
the structure of the digestive tract matches its ___
function
absorption of material in the small intestine requires high ___
surface area
what is the innermost layer of the small intestine that is in contact with food?
muscosa
surface area of esophagus
1cm2
surface area of stomach
30cm2
small intestine surface area
600cm2
surface area of the colon
1cm2
the main function of the small intestine is the ___ and ___ of nutrients and water
digestion and absorption
what are the 3 parts of the small intestine?
- duodenum
- jejunum
- ileum
the duodenum connects to the ____ sphincter
pyloric
the ileum connects to the ___ sphincter
ileocecal
what are 3 disaccharides?
maltose, sucrose, lactose
the ___ enzyme breaks maltose into ____
maltase; 2 glucose
the enzyme ___ breaks sucrose into ___ and ___
sucrase; 1 glucose; 1 fructose
the enzyme ___ breaks lactose into ___ and ___
lactase; glucose and galactose
glucose polymers (such as ___ and ___) are broken down into disaccharides by ____ enzyme
starch and glycogen; amylase
glucose and galactose are absorbed by _____transport by the _____symporter (SGLT)
2ary active; Na
fructose is absorbed by what process? through what channels>
facilitated diffusion; GLUT
amylase acts mostly in the ____, but is also present in the __
pancreas; mouth
what are the 5 enzymes that break down proteins?
- pepsin (from pepsinogen)
- trypsin, chymotrypsin
- amino peptidases, carboxypeptidases
pepsin acts in the ____ for partial breakdown of proteins to ___
stomach; peptides
trypsin and chymotrypsin are secreted by the ___ in inactive forms and are activated in the ___ by ___ and ___
pancreas; small intestine; enteropeptidases and trypsin
amino peptidases and carboxypeptidases are found in the ___ and are responsible for the break down into ___
brush border; single AA
HCL is secreted by ___cells in the stomach and transforms pepsinogen into ___ which breaks the bonds of proteins
parietal; pepsin
pepsinogen is secreted by ___ cells
chief
aside from HCL, parietal cells also secrete ___, ___ and ___
gastrin, histamine, Ach
endopeptidases include ___ in the stomach and ____ and ___ in the small intestine
pepsin; trypsin and chymotrypsin
endopeptidases break what type of peptide bonds?
internal
exopeptidase break what type of peptide bonds?
terminal
exopeptidases can be either ___ or ___
amino peptidases or carboxypeptidases
small peptides are absorbed via cotransport with ___ ions
H
single AA are absorbed via cotransport with ___ ions
Na
small peptides can enter the enterocyte and will be broken down into AA by ____ and then moved across the basolateral membrane by ___ transporters by ___ transport
peptidases; AA; facilitated diffusion