What is the portal vein responsible for?
Conducting all absorbed materials to the liver
It merges vessels that transport nutrients from the digestive tract.
What does the hepatic artery supply to the liver?
Freshly oxygenated blood
This blood is not loaded with nutrients and comes from the lungs.
What are the components of the liver lobule?
- Portal triad
- Central vein
- Bile canalculi
- Parenchyma cells
- Sinusoids
The lobule is the structural unit of the liver.
What is the acinus in the liver?
Functional unit of the liver
It consists of three zones and is involved in metabolic and synthetic functions.
Name the three zones of the hepatic acinus.
- Zone 1
- Zone 2
- Zone 3
Each zone has different metabolic activities.
What are hepatocytes responsible for?
- Metabolic functions
- Synthetic functions
They play a crucial role in liver function.
What is the role of Kupffer cells in the liver?
Breakdown of phagocytosed bacteria
They are specialized macrophages located in the liver.
What is the function of lysosomes in hepatocytes?
- Breakdown of phagocytosed materials
- Deposition of iron, bile pigments, copper, & lipofuscin
They contain hydrolytic enzymes that act as scavengers.
What is the primary function of the smooth endoplasmic reticulum in hepatocytes?
- Conjugation of bilirubin
- Detoxification via cytochrome P450 enzymes
- Synthesis of steroid, cholesterol, & bile acid
It is also the site of most drug metabolism.
What are the biochemical functions of the liver?
- Excretory
- Synthetic
- Metabolic
- Detoxification
- Storage
These functions are essential for maintaining homeostasis.
What is the excretory function of the liver?
Elimination of waste products like bilirubin and bile acids
This function helps in detoxifying the blood.
What is involved in carbohydrate metabolism in the liver?
- Glycolysis
- Gluconeogenesis
- Glycogenolysis
- Glycogenesis
These processes regulate blood glucose levels.
What is the significance of gluconeogenesis?
Conversion of non-carbohydrate moieties to glucose
It helps clear blood of tissue metabolites.
What happens during ketone body formation?
Increased ketone bodies from acetyl-CoA generated from fatty acids
This occurs during carbohydrate shortages.
What are the four functions of bile acids?
- Elimination of excess cholesterol
- Solubilize cholesterol in bile
- Emulsification of dietary triacylglycerols
- Facilitate intestinal absorption of fat-soluble vitamins
Bile acids are crucial for digestion and absorption.
What is the hepatic first-pass effect?
The initial metabolism of drugs by the liver before they enter systemic circulation
It significantly affects drug bioavailability.
What are the phases of drug metabolism?
- Phase I: Hydroxylation, reduction, oxidation, hydrolysis
- Phase II: Conjugation to water-soluble forms
Phase I reactions often involve the cytochrome P450 system.
What is the role of antioxidants in the liver?
Neutralize free radicals
Important antioxidants include beta-carotene and vitamins A, C, and E.
What substances are stored in the liver?
- Glucose as glycogen
- Amino acids
- Iron as ferritin or hemosiderin
- Lipids
- Vitamins (B12, A, D, E, K)
The liver serves as a storage reservoir for essential nutrients.
Hepatic artery
Supplies oxygenated blood to the liver tissue.
Portal vein
Brings nutrient-rich, deoxygenated blood from the gastrointestinal tract to the liver for processing.
Three major functions of the liver
Metabolic – carbohydrate, lipid, and protein metabolism. Synthetic – production of plasma proteins (albumin, clotting factors) and bile acids. Excretory/Detoxification – elimination of bilirubin, ammonia, and drugs.
Carbohydrate metabolic pathways in the liver
Glycolysis, Glycogenesis, Glycogenolysis, Gluconeogenesis.
Principal function of bile and bile acids; storage and release
Function: Emulsify fats, aid in digestion and absorption of fat-soluble vitamins (A, D, E, K), and remove excess cholesterol. Stored in: Gallbladder. Released from: Common bile duct into the duodenum.
