Hepatic Physiology Anesthesia

Front 1

What is largest organ in body and how much does it weigh?

Back 1

liver, 1.5kg

Front 2

How are right and left surgical loves defined by?

Back 2

point of bifurcation of the hepatic artery and portal vein

Front 3

What divides the left surgical lobe into medial and lateral segments?

Back 3

falciform ligament

Front 4

Which lobe is larger and consists of what other lobes?

Back 4

right, consists of two smaller lobes at its posterior-inferior surface-the caudate and quadrate lobes

Front 5

The liver is made up of how many functional units and what are they called?

Back 5

50000-100000 lobules

Front 6

How many portal tracts surrounding each lobule and what are they composed of?

Back 6

four to five
Composed of hepatic arterioles, portal venules, bile canaliculi, lmyphatics, and nerves

Front 7

Zone where cells closest to portal tract, well oxigenated, oxidative metabolism, synthesis of glycogen occurs

Back 7

zone 1

Front 8

transition zone is what?

Back 8

zone 2

Front 9

Zone where cells clostest to centrilobular veins, cytochromep-450 here where biotransformation of drugs, chemicals, and toxins occur
receives the least oxygen and anerobic metabolism
Most susceptible to injury to ischemia, hypoxia, and congestion

Back 9

zone 3

Front 10

The liver is innervated by what nerves? Some autonomic synapse where while others do what?

Back 10

sympathetic fibers T6-T11 and parasympathetic fibers from the right and left vagus nerve, as well as right phrenic nerve

Some autonomic fibers synapse first in the celiac plexus while others reach the liver directly via spanchnic nerves and vagal branches before forming the hepatic plexus

Front 11

What two ways are the liver regulated and give examples?

Back 11

Intrinsic-autoregulation, metabolic control, hepatic arterial buffer response
Extrinsic-neural control, hormones, effects anesthesia

Front 12

Decreases in portal blood flow causes increased hepatic areterial blood flow and this is called?

Back 12

Hepatic arterial buffer response

Front 13

How much blood does the liver receive per minutes?

Back 13

1500ml/min, 25-30% Cardiac Output

Front 14

Where does the blood to liver come from and what percent for each section?

Back 14

Hepatic artery-25-30% 500ml/min
Portal vein-70-75% 1300ml/min

Front 15

How much oxygen supply from hepatic artery/portal vein...and what is average sat?

Back 15

50% O2 supply, sat only 85%

Front 16

What is the normal portal vein and vena cava pressure?

Back 16

portal vein=9mmHg
vena cava=0mmHg

Front 17

What is livers normal blood volume, including hepatic veina and sinuses? How much of total blood volume?

Back 17

450ml, 10% total blood volume

Front 18

When right atrium pressure rises causing back pressure into the liver, the liver does what?

Back 18

expands to 500-1000ml storage of extra blood in hepatic veins and sinuses

Front 19

lympth draining from the liver has a protein concentration of what?

Back 19

6g/dL, slightly less than plasma

Front 20

When the pressure in the hepatic veins rise how much above normal what happens?

Back 20

rises 3-7 mmHg above normal, excess fluid from lympth begins to leak through outer layer of liver capsule directly into abdominal cavity

Front 21

At vena cava pressures of what, hepatic lympth flow increases to as much as 20 times normal and ascites formes. This fluid is what and contains what?

Back 21

10-15mmHg pressure, ascites formes
Fluid is almost pure plasma, containing 80-90% as much protein as plasma

Front 22

What is the filtering cell of liver and how bacteria does it filter?
When these cells not working what happens?

Back 22

kupffers cells(macrophages)
99%
when not working, increased bacteria and causes hepatic encephalopathy

Front 23

What four carbohydrate metabolic functions does the liver do?

Back 23

1 store glycogen (glucose buffer-75grams, gone with/in 24-48 hrs starvation)
2 convert galactose and fructose to glucose
3. gluconeogenesis-(causes large amounts of amino acids and glycerol from triglycerides to be converted to glucose)
4. formation of many chemical compounds from intermediate products of carb metabosism

Front 24

What three fat metabolic functions does the liver perform?

Back 24

1. Oxidation of fatty acids to supply energy for other body functions
2. synthesis of large quantities of cholesterol, phospholipids, and most lipoproteins-(80% of cholesterol synthesized in liver is converted to bile salts and secreted in bile. 20% tranformed with Acetoyl CoA to lipoproteins and stored in body adipose)
3. Synthesis of fat from proteins and carbohydrates

Front 25

What are two metabolic functions of protein metabolism in the liver?

Back 25

1. Deamination of amino acids- required before they can be used for energy or before they can be converted into carbs or fats, 2ammonia +2CO2=urea
2. Formation of urea for removal of ammonia from body fluids

Front 26

How is ammonia formed?

Back 26

large amounts formed by the deamination process and some in gut by bacteria and are absorbed into the blood

Front 27

Where are plasma proteins made?

Back 27

All excep gamma globulins are formed by hepatic cells. Gamma globulins are antibodies formed by plasma cells in the lympth tissues of the body.

Front 28

The liver stores what?

Back 28

Vitamin A, D, B12
Stores Iron as Ferritin, apoferritin combines with iron to form ferritin(storage)

Front 29

What coagulation factors formed by the liver?

Back 29

fibrinogen, prothrombin accelerator globulin, Factor VII

Front 30

What does the liver excrete?

Back 30

drugs, hormones, and other substances

Front 31

What modifies chemical groups through mixed function oxidases or cytochrome P450 enzyme system resulting in oxidation, reduction, deamination, sulfoxidation, dealkylation, or methylation

Back 31

Phase 1 reactions

Front 32

What drugs are inactivated by Phase 1 reactions?

Back 32

Barbiturates and benzos

Front 33

Reaction that involve conjugation of the substance with glucuronide, sulfate, taurine, or glycine. May or not follow other reactions. Conjugated coumpound can be eliminated in urine or bile.

Back 33

Phase II reaction

Front 34

Cytochrome P450 can be induced by what?

Back 34

Ethanol, barbiturates, ketamine, benzos

Front 35

Cytochrome P450 can be prolonged and suppressed by what?

Back 35

cimetidine

Front 36

Drugs dependent on liver function are?

Back 36

lidocaine, morphine, labetalol, propranolol

Front 37

Bile plays an important role in what?

Back 37

fat absorption and in excretion of bilirubin, cholesterol, and many drugs

Front 38

Hepatocytes in each lobule continuously secrete fluid containing what?

Back 38

bile salts, cholesterol, conjugated bilirubin, and other subtances into bile canaliculi

Front 39

bile ducts from all hepatic lobules join to form what?

Back 39

common bile duct

Front 40

Biliary flow from common bile duct into duodenum is controlled by what?

Back 40

sphincter of Oddi

Front 41

the gallbladder communicates with the common bile duct via the what?

Back 41

via the cystic duct and serves as a reservoir for bile

Front 42

A hormone released by the interstinal mucosa in response to fat and protein, causes contraction of the gallbladder, relaxation of the sphincter of Oddi and propulstion of bile into the small intesting

Back 42

cholecystokin, CCK

Front 43

bile acids formed by hepatocytes from cholesterol are essesntial for what?

Back 43

essential for emulsifying the insoluble components of bile as well as facilitating th eintestinal absorption of lipids

Front 44

What is the primary end product of hemoglobin metabolism? What else makes smaller degree?

Back 44

bilirubin
Smaller amount as result of myoglobin and cytochrome enzme breakdown

Front 45

How is bilirubin bound in liver and excreted?

Back 45

Passive hepatic uptake of bilirubin from circulation, but binding to intracellular proteins traps the bilirubin inside the hepatocytes and then bilirubin conjugated and excreted

Front 46

Only two routine tests truly measure hepatic synthetic function?

Back 46

serum albumin concentration
protime

Front 47

None of liver tests are very specific or very sensitive due to what?

Back 47

bc many tests reflect hepatocellular integrity more than hepatic function

Front 48

Liver abnormalitities are often divided into what different disorders and what do they effect?

Back 48

parenchymal-result of generalized hepatocellular dysfunction
obstructive-affect biliary excretion

Front 49

normal serum bilirubin is?
what can/can not be excreted urine?
At what level does jaundice occur?

Back 49

normal 1.4mg/dl
reflect a balance bw production and biliary excretion-unconjugated or indirect or protein bound can not be excreted kidneys and may increase hemolysis
Conjugated or free portion or direct may appear in urine
jaundice at total bilirubin>3mg/dL

Front 50

Enzymes released into circulation as a result of hepatocellular injury or death are?

Back 50

serum aminotransfereases-
AST, SGOT, ALT

Front 51

What is present in many tissues, and what is located in the liver and is more specific for hepatic dysfunction?

Back 51

Ast present many tissues, ALt primarily in liver(more intregity than metabolic function)

Front 52

Nomral AST and ALT levels are?
When do see elevations and when are enzymes released?

Back 52

35-45units/L
Mild elevations with cholestasis and metastatic liver disease
Released from liver cells as they die

Front 53

Produced liver, bone, small bowel, kidneys, and placenta, and is excreted in bile?
What are normal values?
When elevated?

Back 53

Serum alkaline phosphatase, tell difference obstructive or parachmea disease
Normal 45-125 units/L
Mild elevations up to 2x normal are seen with hepatocellular injury or hepatic metastatic disease
Increased levels also with pregnancy or bone disease such as Pagets disease or bone metastatis

Front 54

Normal serum albumin is, what is half life, how much produced by liver daily, what level generally indicative of chronic liver disease or malnutrition

Back 54

Normal 3.5-5.5
Half life 2-3 wks
Liver make 10-15 grams daily
Less than 2.5g/dL are indicative of chronic liver disease or malnutrition

Front 55

Normal phrothrombin time, what factors does it measure, usefull in measuring what, and how much clotting factors needed to maintain normal clotting?
Also how much prolonged a concern, and what is cooresponding INR

Back 55

Prothrombin time-11-14s
Measure fibrinogen, prothrombin, factors V, VII, X
Pt evaluate hepatic synthetic function of pts with acute or chronic liver disease
20-30% of clotting factors needed to have normal clotting
When 3-4 seconds greater a concern-INR 1.5
Prolonged PT usually reflects evere liver disease unless a vitamin K deficiency is present
Failure of PT to return to normal after vitamin K administeration which requires 24 hrs usually implies severe liver disease