Physiology Flashcards
Carbohydrate
product of digestion- glucose, galactose, fructose
site of absorption- small intestine
mechanism- Na/glucose cotransport, Na/galactose cotransport, facilitated diffusion
Proteins
product of digestion- AA, dipeptides, tripeptides
site of absorption- small intestine
mechanism- Na/AA cotransport, H/dipeptide and H/tripeptide cotransport
lipids
product of digestion- fatty acids, monoglycerides, cholesterol
site of absorption- small intestine
mechanism- bile salts from micelles, diffusion of FAs, MAG, and cholesterol, reesterifcation in cell to TG and PLs, chylomicrons form and cell tranferred to lymph
water-soluble vitamins
product of digestion- vitamin B12
site of absorption- small intestine
mechanism- Na+-dependent cotransporter, intrinsic factor
bile salts
product of digestion- bile salts
site of absorption- ileum
mechanism- Na+-bile salt cotransporter
Ca2+
site of absorption- small intestine
mechanism- vitamin D-dependent Ca2+ binding protein
Fe2+
products of digestion- Fe3+ reduced to Fe2+
site of absorption- small intestine
mechanism- binds to apoferritin in intestinal cells, binds to transferrin in the blood
CCK
source- GI tract
stimulus to release- during feeding or just before
target- vagal afferents
effect- limits size of meal
Amylin, insulin, glucagon
source- pancreas
stimulus to release- during or just before feeding
target- vagal afferents
effect- limits size of meal
Peptide YY3-36
source- ileum, colon
stimulus to release- after feeding
target- brainstem, hypothalamus
effect- postpones need for next meal
Glucagon-Like Peptide-1
source- small intestine
stimulus to release- after feeding
target- brainstem, hypothalamus
effect- postpones need for next meal
Oxcyntomodulin
source- small intestine
stimulus to release- after feeding
target- brainstem, hypothalamus
effect- postpones need for next meal
leptin
source- adipose tissue
stimulus to release- adipocity “status”
target- brainstem, arcuate nucleus
effect- longer-term regulation of food intake (decreases appetite and ghrelin release/increases metabolism)
ghrelin
source- stomach
stimulus to release- hunger, feeding
target- vagus, hypothalamus
effect- increases food intake by increasing size and number of meals
