Lecture 35: Hepatic Physiology

Question 1

what artery provides O2 to liver

Answer 1

Hepatic artery

Question 2

What vein transfers nutrients from GI

Answer 2

Hepatic portal vein

Question 3

Is most liver blood venous or arterial

Answer 3

Venous

Question 4

Blood from the liver leaves via the

Answer 4

Hepatic vein

Question 5

What are the functional units of the liver

Answer 5

Lobules

Question 6

What is the function of Kupffer cells

Answer 6

Destroy old RBC and bacteria

Question 7

Vitamin A is stored as __ in __ cells

Answer 7

Retinol, Stellate cells

Question 8

What is the space of Disse

Answer 8

Between hepatocytes a and sinusoids

Question 9

Does blood flow towards or away from central lobule

Answer 9

Towards

Question 10

__ and __ travel towards central lobule whereas ___ travels away

Answer 10

Towards: hepatic artery and portal vein

Away: bile duct

Question 11

What is the outer zone (zone 1)of the hepatocyte called

Answer 11

Periportal

Question 12

What is the inner zone (zone 3) of the hepatocyte called

Answer 12

Centrilobular

Question 13

Which zone has high oxygen tension, many mitochondria. Is concerned with oxidative metabolism, gluconeogenesis, urea, glycogen and bile acid secretion

Answer 13

Zone I

Question 14

Which zone has low oxygen, anaerobic metabolism, biotransformation of toxins, sensitive to ischemic necrosis

Answer 14

Zone III

Question 15

What two capillary beds does blood run through before return to heart

Answer 15

Mesenteric and portal

Question 16

What drives blood through portal capillary bed

Answer 16

Pressure in portal vein is higher than hepatic sinusoids and pre capillary resistance is low

Central vein of liver is large so decreased resistance

Question 17

How does right sided heart failure cause centrilobular congestion and necrosis

Answer 17

Increase in vena cava pressure leads to reduced blood flow to intestines and edema. Less blood to liver, centrilobular portion is most susceptible to hypoxia

Question 18

How does necrosis of hepatocytes in zone 1 (periportal) occur

Answer 18

1. Phosphorus poisoning- rat poison, fertilizer, fireworks
2. Eclampsia

Question 19

How does necrosis of hepatocytes in zone 3 (centrilobular) occur

Answer 19

Ischemic injury, toxins

Question 20

What happens to liver enzymes during necrosis of hepatocytes

Answer 20

Liver enzymes increase as the permeability increases and they leak out

Question 21

What liver enzymes are typically elevated in necrosis of hepatocytes

Answer 21

1. ALT
2. AST
3. ALP
4. GGT

Question 22

How does necrosis of hepatocytes effect synthetic capacity

Answer 22

Decreases

Question 23

How does necrosis of hepatocytes effect cholesterol, glucose, glycogen, insulin, protein and coags

Answer 23

Decrease all

Question 24

How does necrosis of hepatocytes effect conversion of ammonia to urea

Answer 24

Decreases uptake and conversion so increase ammonia concentration in the urine follow by PU/PD

Question 25

Why does a decrease uptake and conversion to urea cause PU/PD

Answer 25

Concentration of urine is dependent on the tonicity of the inner medulla controlled by urea, used to osmotically absorb h20

Question 26

What is the function of bile

Answer 26

1. Excrete solutes 2. Lipid digestion and absoprtion

Question 27

Are are the 2 primary bile acids

Answer 27

Colic acid and chenodeoxycholic

Question 28

The liver conjugates colic acid and chenodeoxycholic with AA taurine and glycine, what are they called

Answer 28

Glycocholic and taurocholic

Question 29

Glycocholic and taurocholic are secreted into intestinal lumen and dehydroxylated by bacteria and produce what 2 secondary bile acids

Answer 29

Deoxycholic and lithocholic

Question 30

How are bile salts reabsorbed in. Distal ileum and throughout intestines

Answer 30

Distal ileum; active transport Intestines: passive transport

Question 31

How are bile salts returned to the liver

Answer 31

Hepatic portal system

Question 32

What is enterohepatic circulation

Answer 32

Bile acids secreted by liver, used for lipid digestion and absorption, reabsorbed by distal ileum and throughout intestines and returned to liver via hepatic portal system

Question 33

What stimulates gallbladder contraction and relaxation of duodenal sphincter to release bile

Answer 33

CCK

Question 34

Describe how bile acid tests work

Answer 34

1. Fast 12hrs 2. Prepranial blood draw 3. Small meal and wait 2hrs 4. Draw blood and test bile acids

Question 35

What could possibly cause increased bile acids 2hrs after a meal

Answer 35

1. Hepatocellular dysfunciton- can’t absorb bile acids 2. Abnormal portal blood fun: shunts so don;t go through liver 3. Cholestasis- interference with transporters that deliver bile

Question 36

What is bilirubin

Answer 36

Degraded heme part of Hb in RBC

Question 37

Bilirubin is bound to what in the blood

Answer 37

Albumin

Question 38

Bilirubin is extracted from blood by hepatocytes and conjugated with

Answer 38

Glucuronic acid

Question 39

Bilirubin glucoronide is secreted into bile and then turned into ___

Answer 39

Bilirubin and urobilirubin

Question 40

What determines color of feces

Answer 40

Oxidized urobilin and stercobolin

Question 41

What form of bilirubin is in the blood

Answer 41

Unconjugated bilirubin bound to albumin

Question 42

What kind of bilirubin is in hepatocyte

Answer 42

Conjugated bilirubin (glucuronic acid)

Question 43

What kind of bilirubin is in the SI—> terminal ileum—> colon

Answer 43

SI: conjugated ileum: urobilinogen Colon: urobilin and stercobilin

Question 44

What can cause increased bilirubin

Answer 44

1. Excessive production via increased RBC destruction (hemolytic anemia) 2. Insufficient removal- block bile ducts

Question 45

If bilirubin does not pass through the liver or passes too quickly through what form of bilirubin is present: conjugated or unconjugated

Answer 45

Unconjugated

Question 46

If something prevents the secretion of bilirubin into bile what form of bilirubin is present: conjugated or unconjugated

Answer 46

Conjugated

Question 47

Jaundice is a result of bilirubin production ___bilirubin excretion

Answer 47

Exceeding

Question 48

What causes pre-hepatic/hemolytic jaundice

Answer 48

Breakdown of RBC—> liver gets more bilirubin than it can handle

Question 49

What causes hepatic jaundice

Answer 49

Liver disease unable to deal with normal amounts of bilirubin

Question 50

What causes post hepatic/obstructive jaundice

Answer 50

Bile duct is blocked (gallstone) bilirubin not excreted

Question 51

What are Chloelithiasis

Answer 51

Stones in bile duct or gallbladder

Question 52

How do cholethiasis affect feces color

Answer 52

Decrease urobilin and stercobilin secretion—> lighter or grey

Question 53

What is the treatment for cholethiasis

Answer 53

Low fat/high protein diet, sx

Question 54

What type of hyperbilirubin is a result of cholethiasis: conjugated or unconjguated

Answer 54

Conjugated

Question 55

What causes neonatal isoerythrolysis/jaundice foal

Answer 55

Mare creates antibodies to foals RBC which are secreted in RBC and results in hemolytic anemia—> increased bilirubin to liver, more than it can excrete

Question 56

What type of hyperbilirubin is neonatal isoerythrolysis/ jaundice foal

Answer 56

Unconjugated

Question 57

How can you test for neonatal isoerythrolysis/ jaundice foal

Answer 57

Milk and foal blood agglutination test