Lecture 7- Gastrointestinal Flashcards
5 basic categories of useable food (energy sources)
carbs proteins fats vitamins minerals
glucose/galactose is brought into the cell by …. transporter
SGLT1
fructose is brought into the cell by …. transporter
GLUT5
Monosacarrhides (Glucose, galactose and fructose) are brought into the blood by …
GLUT2
complex carbs are broken down into …. by … and …
monosaccharides
amylase
lactase
after complex carbs are broken down, the monosaccharides are taken up by epithelial cells by… and …. and then passed into the blood by…
SGLT1
GLUT5
GLUT2
proteins are broken down into peptides in 2 locations
stomach
small intestine
in the stomach, …is produced which is cleaved to …. and this degrades proteins
pepsinogen
pepsin
the pancreas releases these 4 pro-enzymes into small intestine to digest proteins. They must be converted into active enzymes which is initiated by …
trypsinogen
cymotrypsinogen
procarboxypeptidase A&B
proelastase
enteropeptidase
… is an essential protease for cleavage of proteins
trypsin
where is the enteropeptidase located
brush border
peptides are broken down into
amino acids
2 broad classes of transporters for amino acids:
Na dependent
Na independent
T/F the subclasses of transporters are not specific for certain types of amino acids
false
transporters for amino acids are located on … and ….
brush border
basolateral membrane
protein is degraded by … and …
HCl and proteases
T/F ALL of the proteases that degrade protein are released as proenzymes
true
Triglyceride is broken down into …. and …. by ….
monoglyceride
2 fatty acids
lipase
3 sources of lipase
lingual
gastric
pancreatic
fatty acid absorption occurs in the … (primarily ….) but digestion occurs in … and …
small intestine
duodenum
stomach
duodenum
T/F fats are not water soluble but lipases are
true
fat films are emulsified … and by …. agents
mechanically
emulsifying
gastric emptying is slowed by …
fats
… help to breakdown a fat globule into droplets
bile salts (glycocholic acid) and phospholipids
how does lipase interact with fat?
colipase
colipase breaks down fat droplets into …
micelles
how do micelles enhance absorption of fatty acids?
- micelles are in equilibrium with free fatty acids
2. micelles are constantly breaking down and reforming
T/F fatty acids and monoglycerides are found in the blood
false. triglycerides are
how is B12 brought into the cell?
intrinsic factor
water soluble vitamins are absorbed by facilitated or active transport except …
B12
most water absorption occurs in the …
small intestine
water follows the concentration gradients of solutes which is dependent upon …
Na+
what dictates water absorption in the small and large intestine?
Na+
T/F absorption of Na can occur against a small electrochemical gradient
true
Na absorption is highest in areas where ….
glucose/galactase or amino acids are being transported
Cl-, HCO3, K+ are absorbed in part due to …
Na+
absorption of calcium is strongly enhanced by …
vitamin D
Calcium is absorbed by … and are soluble at …
all segments of the small intestine
low pH
Absorption of Fe2+ is very ….
inefficient (less than 10% absorbed)
… enhances absorption of Fe2+
stomach
Can Fe3+ be absorbed?
no
