Liver Lecture Flashcards
Largest organ in the body
Liver
T/F Liver only has exocrine fxn
F
Exocrine and endocrine fxn
Give blood supply and drainage of the liver
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
Major fxns of liver
Metabolism (protein, CH2O, etc) Storage (lipids, vtamins) Secretion (bile) Synthesis (fibrinogen, etc) Detox Destruction of RBC Hemopoiesis Phagocytosis
Zenobiotic metabolism
Metabolism of foreign objects
–>conversion of lipophilic chemical cmpds to excreted hydrophilic products. Determines duration/intensity of drug’s action
Phases of zenobiotic metabolism
Phase 1-modification
Phase 2-Conjugation
Phase 3-Further modification and excretion
Gives some routes of drug metabolism
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
How is bilirubin processed?
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
Parenchyma of liver
hepatocytes, perform almost all the functions of liver
Central v purpose
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
T/F Hepatocytes can regenerate
T
Sinusoids
-what are they
Discontinuous capillary comng from portal v and hepatic a
Gaps btw pores in endothelial cells
Merge into CV
Kupffer cells live here
Space of Disse
- What is it
- Supported by
- Filled with
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.
Bile canaliculi
- What is it NOT
- Describe orientation
- Active process
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
How to test liver integrity
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
How to test liver function
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
Characteristics of classical lobule
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
Characteristics of portal lobule
Focus on exocrine fxn Triangular region Center is portal area Border is imaginary lines connecting 3 CV Bile flows towards center
Characteristics of hepatic acinus
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.
What makes up stroma of liver?
Liver capsule
Perivascular fibrous tissue
Portal area
- define
- what’s in it
Area where 3 classical lobules join each other
Houses: hepatic a, portal v, bile ducts, nerve fibers, lymph vessels
Blood flow vs bile duct flow
Blood flows from periphery to center of lobule
Bile flows from center of lobule to periphery via bile canaliculi
What are Kupffer cells
Residential MQ of liver
Pathologies of the liver
Fatty liver
Glycogen accumulation
Cirrhosis
