Liver Lecture

Question 1

Largest organ in the body

Answer 1

Liver

Question 2

T/F Liver only has exocrine fxn

Answer 2

F

Exocrine and endocrine fxn

Question 3

Give blood supply and drainage of the liver

Answer 3

Receives 75% from portal v (oxygen poor/nutrient rich)

Receives 25% from hepatic a (O2 rich)

Blood leaves via hepatic v and vena cava

Capillary in GI tract–>portal v–>sinusoids in liver–>central v–>sublobular v–>hepatic v–>vena cava

Question 4

Major fxns of liver

Answer 4

Metabolism (protein, CH2O, etc)
Storage (lipids, vtamins)
Secretion (bile)
Synthesis (fibrinogen, etc)
Detox 
Destruction of RBC
Hemopoiesis
Phagocytosis

Question 5

Zenobiotic metabolism

Answer 5

Metabolism of foreign objects
–>conversion of lipophilic chemical cmpds to excreted hydrophilic products. Determines duration/intensity of drug’s action

Question 6

Phases of zenobiotic metabolism

Answer 6

Phase 1-modification
Phase 2-Conjugation
Phase 3-Further modification and excretion

Question 7

Gives some routes of drug metabolism

Answer 7

Drug–>Phase 1–>Cytochrome p450 adds -OH to create metabolite–>excretion

Drug–>Phase 1–>Phase 2–>Conjugation enzymes add conjugate to create metabolite–>Excretion

Drug–>Phase 2 and same as above

Drug–>Phase 1–>Phase 2–>Metabolite with ROS and conjugate–>excretion

Question 8

How is bilirubin processed?

Answer 8

Hemoglobin is broken down into heme and globin. Heme is convertd to Fe and protoporphyrin–>biliverdin–>bilirubin

Bilirubin is released from MQ and bound to albumin and transported to liver

When bilirubin is conjugated with glucuronic acid, it s soluble.

Secreted bile–>bacterial reduction–>urobilinogen

• ->90% excreted in feces as stercobilinogen
• ->10% renal excretion

Question 9

Parenchyma of liver

Answer 9

hepatocytes, perform almost all the functions of liver

Question 10

Central v purpose

Answer 10

Each lobule has CV that receives blood from every sinusoid.

As CV leaves lobule, it terminates in sublobular v which drains into the hepatic v

Question 11

T/F Hepatocytes can regenerate

Answer 11

T

Question 12

Sinusoids

-what are they

Answer 12

Discontinuous capillary comng from portal v and hepatic a
Gaps btw pores in endothelial cells
Merge into CV
Kupffer cells live here

Question 13

Space of Disse

• What is it
• Supported by
• Filled with

Answer 13

Narrow space btw hepatocytes and endothelial cells supported by reticular fibers and collagen fibers.

Filled with plasma

Hepatocytes form microvilli to occupy most space

Ito cells may be found in this space.

Question 14

Bile canaliculi

• What is it NOT
• Describe orientation
• Active process

Answer 14

NOT A DUCT

Dilated intercellular space between adjacent hepatocytes.

Apical side of hepatocytes faces sinusoids and basal side are welded together to form canaliculi.

Blood runs on apical side of hepatocytes and bile runs in opposite direction on basal side.

Bile canaliculi is an ACTIVE structure using ATP-ase

Question 15

How to test liver integrity

Answer 15

Look for liver enzymes in serum which don’t have biological function in blood

Increased level may mean injury or necrosis of liver

Leakage=ALT, AST, SDH, CK
Inducible=ALP,ALK,AP,SAP,GGT

Question 16

How to test liver function

Answer 16

Concentration of substance removed from blood by liver then metabolized and excreted via biliary system
–>Bilirubin, bile acids, cholesterol, ammonia

Increased concentration of substance synthesized by liver
–>Albumin, globulin, urea, cholesterol, glucose, coagulation factors

Question 17

Characteristics of classical lobule

Answer 17

Defined CT border
Formed by hepatocyte plates
Sinusoids merge into CV that’s in center of lobule
Blood flows from periphery to center
Bile flows from center to periphery via bile canaliculi

Question 18

Characteristics of portal lobule

Answer 18

Focus on exocrine fxn
Triangular region
Center is portal area
Border is imaginary lines connecting 3 CV
Bile flows towards center

Question 19

Characteristics of hepatic acinus

Answer 19

Defined by concept of blood flow and metabolism
Centered by terminal vessels
Outlined by two portal areas and two central veins
Poorly defined three zones
Blood flows from zone 1 to zone 3
–>Zone 1 sees blood first and toxins first.
–>If zone 3 is affected, may be metabolic problem.

Question 20

What makes up stroma of liver?

Answer 20

Liver capsule

Perivascular fibrous tissue

Question 21

Portal area

• define
• what’s in it

Answer 21

Area where 3 classical lobules join each other

Houses: hepatic a, portal v, bile ducts, nerve fibers, lymph vessels

Question 22

Blood flow vs bile duct flow

Answer 22

Blood flows from periphery to center of lobule

Bile flows from center of lobule to periphery via bile canaliculi

Question 23

What are Kupffer cells

Answer 23

Residential MQ of liver

Question 24

Pathologies of the liver

Answer 24

Fatty liver

Glycogen accumulation

Cirrhosis