Download Lingual Lipase

Lipids: Triacylglycerols
Cholesterol esters
Phospholipids
Triacylglycerols
Lingual
Lipase
1a
Lingual Lipase
("acid-stable")
FFA + DAGs
(miniscule
amounts)
MOUTH
FFA + DAGs
(small amounts)
1b
STOMACH
STEP 1: Digestion in the Mouth and Stomach
Courtesy of Dr. Marc Tischler
EXOCRINE
PANCREAS
CCK-PZ
stimulates
secretion
trypsinogen,
procolipase,
lipase, esterase,
HCO3-, proPLA2
Bile Acid
Synthesis
Conjugation
FFA
Bile Salt
storage
GALL
BLADDER
Pancreatic
ProPLA2
Courtesy of Dr. Marc Tischler
Endocrine
cell
Cholecystokinpancreozymin
Trypsinogen
(CCK-PZ)
via bloodstream
Pancreatic
lipase
SMALL
INTESTINE
duodenum/jejunum
Pancreatic
Procolipase
LIVER
CCK-PZ causes
contraction
from stomach
Pancreatic
esterase
STEP 2: Enzymatic Digestion in the
Duodenum/Jejunum –
secretion of zymogens/bile salts
SMALL
INTESTINE
duodenum/jejunum
LIVER
Enterohepatic
circulation of
bile acids
3b
Mixed
Micelles
4
3b
Released
bile acids
Portal
vein
Reabsorbed
by ileum
STEP 3b: Bile Acid Recycling
STEP 4: Lipid Absorption
Courtesy of Dr. Marc Tischler
FFA,
2MG
cholesterol
lysolecithin
vitamin A
Short/medium
chain FFA
Capillaries
SMALL
INTESTINE
duodenum/jejunum
B48
6b
Chylomicron
Triacylglycerol
transfer protein
6a
Coating with
apolipoprotein
(with TTP)
Triacylglycerol
5
vitamins
D, E, K
Cholesterol
ester
Phospholipid
ACAT
reesterification
FFA,
2MG
STEP 5: Re-esterification
STEP 6: Chylomicron Assembly
and Export
Courtesy of Dr. Marc Tischler
To lacteals and
thoracic duct
(lymphatic
system)
cholesterol
lysolecithin
vitamin A
Acyl CoA:
cholesterol acyl
transferase
I
N
T
E
S
T
I
N
E
Lymph system:
Chylomicrons
to capillaries
via lymph
chylomicron interacts
with lipoprotein lipase
removing FFA
Nascent chylomicrons acquire
apo CII (C) and E
(E) from HDL
non-hepatic tissues
CE
CE
CECE
CE
CECE
CE CE
ApoB48 aids
with chylomicron
assembly
LIVER
Chylomicrons carry dietary fatty acids to tissues and the remnants take
cholesterol to the liver
I
N
T
E
S
T
I
N
E
Lymph system:
chylomicron interacts
with lipoprotein lipase
removing FFA
chylomicron
acquires apo
CII (C) and E
(E) from HDL
non-hepatic tissues
CE
CE
CECE
CE
CECE
CE CE
C
E
ApoB48
chylomicron
remnants lose
CII to HDL
E
C
E
E C
EE E
Liver: apo E receptor
takes up remnants to
deliver cholesterol
LIVER
Chylomicrons carry dietary fatty acids to tissues and the remnants take
cholesterol to the liver
Courtesy of Dr. Marc Tischler