Transcript HR Development Program For CDMA

Biliary System
Dr. Mahvash Khan
Biliary System
Includes
 Liver
 Gallbladder
 Ducts
Liver is the largest organ in the body
 Liver Has Very High Lymph Flow (half of the
lymph formed in the body under resting
conditions)
 Liver Has High Blood Flow and Low Vascular
Resistance (1350 ml/min) (27% of the cardiac
output)
 The basic functional unit of liver is the “liver
lobule”(50,000-1000,000)
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Blood Supply of Liver
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Sources (Two)
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Hepatic Artery
Hepatic Portal Vein
Blood is drained into
Hepatic Vein which joins
inferior venacava
Physiologic Anatomy of Liver
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Functional Units (Lobules)
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Hexagonal Arrangement of
Tissues around central Vein
Branch of Hepatic Artery,
Hepatic portal vein and
a bile duct at the outer edge
of Lobule
Functions of liver
Metabolic Functions
 Synthetic Functions
 Storage Functions
 Blood reservoir
 Hemopoietic Function
 Blood Cleansing Function
 Activation of Vitamin-D
 Excretory Functions
 Digestive Function
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Functions of liver- Metabolic Functions
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Carbohydrate Metabolism
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Blood Glucose Buffer system
Storage of Glycogen
Conversion of Galactose & Fructose to Glucose
Gluconeogenesis
Formation of Many chemical compounds from
intermediate products of Carbohydrate metabolism
Protein Metabolism
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Deamination of Aminoacids
Formation of Urea
Synthesis of Plasma Proteins
Synthesis of Clotting Factors
Interconversion of Various Amino acids
Functions of liver- Metabolic Functions (Con’d)
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Fat Metabolism
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Oxidation of Fatty acids to supply energy
Synthesis of cholesterol, phospholipids &
lipoproteins
Synthesis of fat from proteins & carbohydrates
Functions of liver- Synthetic Functions
Synthesis of plasma proteins
 Synthesis of clotting factors (factor VII,
IX, X, prothrombin, fibrinogen)
 Synthesis of various proteins required for
the transport of Steroid & Thyroid
Hormones
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Functions of liver- Storage Functions
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Storage of:
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Iron
Copper
Glycogen
Vitamins (A,D,B12)
Functions of liver- Blood reservoir & Hemopoietic Function
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Blood Reservoir (Blood sinusoids-dilated
capillaries)
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Hemopoietic Function
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In fetal life
Functions of liver- Blood Cleansing Function
Removal of bacteria (by Kupfer cells)
 Detoxification of drugs & chemicals (like
penicillin, sulfonamides)
 Removal of old red blood cells
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Functions of liver- Activation
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of Vitamin-D
Formation of 25 hydroxycholecalciferol
Functions of liver- Excretory
Excretion
 Excretion
 Excretion
 Excretion

of
of
of
of
Functions
calcium through gut
bilirubin
cholesterol
hormones
Functions of liver- Digestive Functions
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Role of Bile salts in digestion & Absorption
of fats
Bile Secretion by Liver
Bile is secreted by Liver
 Normally between 600 and 1000 ml/day
 Bile is secreted in two stages
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Bile plays an important role in fat digestion
and absorption
 Bile serves as a means for excretion of several
waste products from the blood such as bilirubin,
(end product of hemoglobin destruction), excess
cholesterol, certain hormones etc
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Composition of Bile
Water
Liver Bile
97.5 g/dl
Gallbladder Bile
92 g/dl
Bile salts
Bilirubin
Cholesterol
Fatty Acids
1.1
0.04
0.1
0.12
6 g/dl
0.3 g/dl
0.3-0.9 g/dl
0.3-1.2 g/dl
Lecithin
Na+
K+
0.04 g/dl
145 mEq/l
5 mEq/l
0.3 g/dl
130 mEq/l
12 mEq/l
Ca++
ClHCO3-
5 mEq/l
100 mEq/l
28 mEq/l
23 mEq/l
25 mEq/l
10 mEq/l
g/dl
g/dl
g/dl
g/dl
Secretion of Bile by liver
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250 ml to 1 liter per day
Continuous secretion by hepatocytes
Aqueous alkaline fluid
Important organic constituent
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Bilirubin
Cholesterol
Lecithin
Bile salts
Taken by common bile duct to the duodenum
Enterohepatic circulation
Bile Salts
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Derivatives of Cholesterol
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Cholic acid & Chenodeoxycholic acid
Conjugation with glycine & taurine
Sodium salts of conjugated acids
Average amount 3 to 4 gms in the body
 Only 5% excreted in faeces
 Powerful choleretics
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Stimulus for Bile secretion
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Chemical Mechanism
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Hormonal Mechanism
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Bile Salts
Secretin
Neural Mechanism
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Vagalstimulation
Gallbladder
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Site
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Sac like structure
Located beneath the liver
Functions
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Storage of bile
Concentration of bile
Gallbladder Functions: Storage of bile
Can store 450 ml of bile (12 hr of
secretion)
 Transported to the Gallbladder between
the meals
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Gallbladder Functions: Concentration of bile
Active transport of salts
 Water following osmotically
 Concentration of bile 5 to 10 times
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Gallbladder : Emptying of Gallbladder
Relaxation of sphincter of ODDI
 Contraction of gallbladder
 Role of cholecystokinin
 Stimulation by fatty foods in duodenum
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Gallbladder : Formation of Gall stones
Common site of formation of stones
 75% of stones made of cholesterol
 25% made of bilirubin
 In case of Gallbladder removal bile is
stored in common bile duct which
becomes dilated
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