Podcast
Questions and Answers
What percentage of the liver's blood supply is typically provided by the hepatic artery?
What percentage of the liver's blood supply is typically provided by the hepatic artery?
Which of the following is NOT a component of the portal triad found within the hepatic lobules?
Which of the following is NOT a component of the portal triad found within the hepatic lobules?
The liver is attached to which of these through the coronary ligament?
The liver is attached to which of these through the coronary ligament?
Blood flows out of the liver into which vessel?
Blood flows out of the liver into which vessel?
Signup and view all the answers
The hepatic lobule is structured as a hexagon, with portal triads located at each:
The hepatic lobule is structured as a hexagon, with portal triads located at each:
Signup and view all the answers
What is the primary direction of blood flow within liver sinusoids?
What is the primary direction of blood flow within liver sinusoids?
Signup and view all the answers
What is the correct sequence of blood flow in the liver, starting from the initial vessels?
What is the correct sequence of blood flow in the liver, starting from the initial vessels?
Signup and view all the answers
Which structure is considered the functional unit of the liver?
Which structure is considered the functional unit of the liver?
Signup and view all the answers
Within the hepatic acinus, which zone is primarily associated with detoxification?
Within the hepatic acinus, which zone is primarily associated with detoxification?
Signup and view all the answers
Which of the following is NOT a key function associated with the hepatocytes in Zone 1 of the hepatic acinus?
Which of the following is NOT a key function associated with the hepatocytes in Zone 1 of the hepatic acinus?
Signup and view all the answers
What type of cells make up the majority of the liver's mass?
What type of cells make up the majority of the liver's mass?
Signup and view all the answers
Hepatocytes have a high number of which organelle to support the liver's metabolic functions?
Hepatocytes have a high number of which organelle to support the liver's metabolic functions?
Signup and view all the answers
Which structure do hepatocytes lie adjacent to?
Which structure do hepatocytes lie adjacent to?
Signup and view all the answers
Which zone of the hepatic acinus is considered to have mixed function between zones 1 and 3?
Which zone of the hepatic acinus is considered to have mixed function between zones 1 and 3?
Signup and view all the answers
What hormone is responsible for controlling bile flow into the duodenum?
What hormone is responsible for controlling bile flow into the duodenum?
Signup and view all the answers
What is the primary source of heme that is broken down to produce bilirubin?
What is the primary source of heme that is broken down to produce bilirubin?
Signup and view all the answers
Which process makes unconjugated bilirubin soluble for transport in plasma?
Which process makes unconjugated bilirubin soluble for transport in plasma?
Signup and view all the answers
What is the final step of bilirubin metabolism before it is excreted in feces?
What is the final step of bilirubin metabolism before it is excreted in feces?
Signup and view all the answers
What structural component controls the flow of bile and pancreatic secretions into the duodenum?
What structural component controls the flow of bile and pancreatic secretions into the duodenum?
Signup and view all the answers
What is the characteristic color of bilirubin, indicating its presence in bile?
What is the characteristic color of bilirubin, indicating its presence in bile?
Signup and view all the answers
What are the primary functions of Kupffer cells in the liver?
What are the primary functions of Kupffer cells in the liver?
Signup and view all the answers
What role do stellate cells play when activated by injury or inflammation?
What role do stellate cells play when activated by injury or inflammation?
Signup and view all the answers
Where are Kupffer cells located within the liver?
Where are Kupffer cells located within the liver?
Signup and view all the answers
What is the definitive role of the hepatic sinusoids in the liver?
What is the definitive role of the hepatic sinusoids in the liver?
Signup and view all the answers
What is the main function of cholangiocytes in the liver?
What is the main function of cholangiocytes in the liver?
Signup and view all the answers
What anatomical feature distinguishes the hepatic lobule's structure?
What anatomical feature distinguishes the hepatic lobule's structure?
Signup and view all the answers
How do bile canaliculi contribute to the biliary system?
How do bile canaliculi contribute to the biliary system?
Signup and view all the answers
Where is the gall bladder situated in relation to the liver?
Where is the gall bladder situated in relation to the liver?
Signup and view all the answers
What is the primary composition of the hepatic lobule?
What is the primary composition of the hepatic lobule?
Signup and view all the answers
What happens to stellate cells when they are activated?
What happens to stellate cells when they are activated?
Signup and view all the answers
Study Notes
Liver Anatomy & Physiology
- The liver is a large, essential organ located in the upper right quadrant of the abdomen.
- It has a right and left lobe.
- The liver weighs approximately 1.4-1.8 kg in adults and slightly less in women.
- A key feature of the liver is its remarkable ability to regenerate if a portion is lost or removed surgically.
- It's considered the body's "chemical factory" performing multiple crucial functions.
Liver Objectives
- Analyze the liver's vascular, parenchymal, and biliary anatomy.
- Detail the structure and function of the hepatic lobule, stellate, and Kupffer cells.
- Describe the steps involved in bilirubin metabolism.
- Discuss the liver's role in metabolism, synthesis, detoxification, immunity, and digestion.
Liver Overview
- The liver has a dual blood supply, receiving oxygenated blood from the hepatic artery and deoxygenated blood from the hepatic portal vein containing nutrients from the digestive tract.
- Venous blood exits the liver through the hepatic veins.
- The liver is not vascularized with a capillary network like most other organs. Instead, blood flows through sinusoids surrounding the hepatic cells.
Liver Anatomy
- The liver has three distinct compartments: vascular, parenchymal (histological), and biliary.
- The liver is divided into anatomically distinct segments (Couinaud's segments).
- Each segment has its own hepatic artery, portal vein, hepatic vein and biliary branches.
Liver - Vascular Anatomy
- The hepatic artery delivers oxygen-rich blood.
- The hepatic portal vein brings deoxygenated blood, rich in nutrients absorbed from the digestive tract.
- These two sources mix within the sinusoids.
- Blood exits the liver via the hepatic vein.
Hepatic Blood Flow
- Hepatic vein
- Sinusoids
- Segmental hepatic artery and portal vein
- Hepatic artery and portal vein
- Lobular hepatic arteriole and hepatic venule
Hepatic Lobule - Anatomy
- Hepatic lobules are the fundamental functional units of the liver tissue.
- Arranged in a hexagonal shape.
- Each lobule contains a portal triad (hepatic artery, portal vein, bile duct) at each corner.
- Hepatocytes are arranged in cords between sinusoids and a central vein.
- Hepatic acinus is a functional unit within a lobule. It has distinct zones related to blood access.
Hepatocytes
- Hepatocytes are the dominant cell type (about 80%) in the liver.
- Round in shape, containing a nucleus, endoplasmic reticulum, Golgi apparatus, and numerous mitochondria.
- Responsible for various metabolic functions.
- Some hepatocytes are near the sinusoidal walls (which are formed by endothelia) separated by the space of Disse.
Supporting Cells: Kupffer Cells
- Kupffer cells are mononuclear phagocytic cells located in the hepatic sinusoids.
- Play a crucial role in breaking down red blood cells and removing bacteria.
- Part of the liver's innate immune response.
Supporting Cells: Stellate Cells
- Stellate cells are located in the perisinusoidal space (Space of Disse).
- Responsible for vitamin A storage and metabolism.
- When activated by injury/inflammation, they transform into collagen-producing myofibroblasts contributing to hepatic fibrosis.
Liver Components
- Hepatocytes form cords between a highly specialized capillary network and the central vein.
- Supporting cells, like Kupffer cells and stellate cells, live within and around the sinusoids and space of Disse.
Biliary System
- Bile is produced by hepatocytes and released into bile canaliculi.
- Bile canaliculi merge to form larger bile ducts, eventually leading to the common bile duct.
- Bile salts are crucial for fat digestion and absorption.
- Enterohepatic circulation explains the continuous recycling of bile salts.
Gall Bladder
- Stores and concentrates bile.
- Releases stored bile into the small intestine when needed for fat digestion.
- Controlled by hormones like cholecystokinin.
Bilirubin Metabolism
- Bilirubin is a yellowish pigment made as a byproduct of the breakdown of red blood cells.
- This breakdown process occurs in mononuclear phagocytes.
- Bilirubin is initially insoluble, transported by albumin, then conjugated within hepatocytes.
- Conjugated bilirubin is excreted into bile, processed in the gut, then eliminated in feces.
Physiologic Neonatal Jaundice
- Jaundice is a condition where bilirubin levels can accumulate, leading to a yellowish hue in the skin or eyes.
- In newborns indirect bilirubin is a typical problem and usually mild and transient. The neonatal liver has reduced capacity to conjugate bilirubin.
Liver Functions: Metabolism and Synthesis
- The liver plays a vital role in glucose homeostasis (glycogenesis, gluconeogenesis).
- It also regulates fat metabolism (lipogenesis, lipolysis), synthesizes cholesterol, and plays a role in amino acid metabolism.
- The liver synthesizes essential plasma proteins like albumin and clotting factors.
Liver Functions: Detoxification and Immunity
- The liver detoxifies various endogenous and exogenous substances.
- Ammonia, a toxic byproduct of protein metabolism, is converted to urea by the liver and excreted.
- The liver is populated by immune cells monitoring antigens (like from food) to maintain tolerance within the body.
Liver Functions: Digestion
- The liver produces bile, which is transported to the small intestine.
- Bile salts aid in fat and fat-soluble vitamin absorption.
- Enterohepatic circulation cycles bile salts for continuous recycling and use.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
Test your knowledge on the anatomy and physiology of the liver. This quiz covers key aspects such as liver structure, functions, and its role in metabolism and detoxification. Dive into details about the hepatic lobule and bilirubin metabolism for a comprehensive understanding of this vital organ.
