Liver! Flashcards
(37 cards)
Major Components of the liver:
Structural framework
connective tissue capsule, trabeculae and reticular network forms the framework for hepatic architecture
Sinusoids and hepatic cords
biliary tree
Major components of the liver
Cells of the liver
hepatocytes
Kupffer cells
Stellate cells
Endothelial cells
Biliary epithelium
liver architecture
Hepatic Architecture
Hepatic Lobule
an anatomic unit with the central vein at the center of the lobule and portal triads at the periphery
Hepatic Acinus
a functional unit with the central axis bridging between portal areas, with the outer part of the acinus around the central vein
Hepatocytes
- Account for approximately 80% of total liver mass
- Arranged in branching, single-cell plates between sinusoids
- Numerous microvilli on the surface facing the sinusoid
- Responsible for most of the synthetic, secretory, storage, detoxification and metabolic functions of the liver
- Contain numerous intracellular organelles
- Produce and secrete bile into bile canaliculi
Kupffer cells
- member fo the mononuclear phagocyte system
- mobile macrophages located within the sinusoids
- Phagocytose immune complexes and particulate matter in the sinusoids
- produce pro-inflammatory and anti-inflammatory cytokines to contribute to innate immunity
- Pro-inflammatory products can activate hepatic stellate cells to create collagen
Hepatic Stellate Cells
Located in the space of disse
normal function is storage of Vitamin A
During hepatic injury they convert to a myofibroblast phenotype and produce collagen and other ECM components to promote hepatic fibrosis
Sinusoidal Endothelium
- Second most common cell in the liver
- 15-20% of all cells
- 3% of liver mass
- Contain numerous fenestrae
- They lack a well organized basement membrane
- Discontinuous capillary allows intimate contact with blood components and hepatocytes
- Facilitate exchanges between plasma and hepatocytes
Blood Vessels
liver has dual blood supply
Hepatic artery
Protal vein
Blood flow is from portal triad to central vein
Discontinuous capillary with fenestrated endothelium allows intimate contact with blood components and hepatocytes
Lymphatic Vessels
- Fluid from the hepatic interstitium flows into the space of disse then to the portal interstitum to the portal lymphatics
- fluid is derived form the blood as well as products of hepatocytes, hepatic stellate cells and kupffer cells
- Liver accounts for 50% of the lymph that enters the thoracic duct
- Role of lymphatics in disease is poorly understood
- obesity, lipidosis, hypercholesterolemia, lipoprotien associated disease
Biliary System
- Bile is transported form the hepatocyte through a progressively enlarging duct system for secretion into the small intestine
- bile canaliculi
- Intrahepatic bile ductules
- Interlobular bile ducts
- interlobar ducts
- Lobar ducts
- Extrahepatic bile duct
Comparative Hepatic Anatomy:
How many lobes?
Dogs and Cats
6
left lateral, left medial, quadrate, right medial, right lateral, cuadate
Comparative Hepatic Anatomy:
How many lobes?
Mice and Rats
4
right, caudate, left, middle
Comparative Hepatic Anatomy:
How many lobes?
Horse
5
Right, Quadrate, left medial, left lateral, caudate
Comparative Hepatic Anatomy:
How many lobes?
Bovine
4
right, caudate, left, quadrate
Comparative Hepatic Anatomy:
How many lobes?
Elephant and Chicken / Avian
2
Left, right
Comparative Hepatic Anatomy:
How many lobes?
Pig
5
left medial, left lateral, right medial, right lateral, cuadate
Comparative Hepatic Anatomy:
How many lobes?
Humans
4
left, right, quadrate, cuadate
Who doesn’t have a gallbladder?
- Equines
- horses, mules, etc.
- Cervids
- white-tailed deer, elk, moose, etc
- Camels
- Rats
- Elephants
- Giraffes
- but often present in neonates, involuting with age
- Rhinoceroses
- Doves, pigeons, ostriches, and some psittacines
- but most avian species have gall bladder
- Among others
Liver Function
- The liver plays a central role in metabolism
- synthesis and metabolism of proteins, lipids, and carbohydrates
- Storage of nutrients
- conjugation and detoxification reactions
- Immune functions
- Waste product excretion
- Bile synthesis and secretion
Nutrient synthesis, storage, and metabolism
Glucose metabolism
Degradation of plasma lipids and synthesis / storage / oxidation of fatty acids
Production of most plasma proteins
Production of cholesterol and lipoproteins
Nutrient storage
Conjugation and Detoxification
Xenobiotic biotransformation and excretion
- Phase 1 reactions:
- Convert toxins into less (sometimes more) harmful intermediate compounds
- Cytochrome P-450
- Convert toxins into less (sometimes more) harmful intermediate compounds
- Phase 2 reactions
- convert phase 1 products into water soluble products for excretion
- conjugation reactions
- glucuronidation
- Sulfation
- Glutathione and amino acids conjugations
- conjugation reactions
- convert phase 1 products into water soluble products for excretion
