Hepatic Physiology Flashcards
The basic functional unit of the liver is the ________
Liver Lobule
The liver lobule is constructed around a _____, which empties into the ______
Central Vein; Hepatic Vein
The liver can be compared to being the “_________” center of the body
waste management
The lobules are composed of many ______, which are collections of ______ that radiate out from the central vein like spokes of a wheel
Cellular Plates; Hepatocytes
Adjacent to the hepatocytes are _______ that collect bile secreted by the hepatocytes and empty into Bile Ducts
Bile Canaliculi
What are small branches of the portal vein called? Where do they transport blood from?
Portal Venules; Transport venous blood coming in from the gastrointestinal system
Trace the path of blood from GI system to the IVC through the liver
GI > Hepatic portal vein > Portal Venules > Hepatic sinusoids > Central Vein > Hepatic Vein > IVC
Where hepatic arterioles supply blood to?
providing oxygenated blood to the lobule
The sinusoids are lined by endothelial cells and large ______
Kupffer Cells (gate keeper cells)
The spaces between the lining of the sinusoid and the cellular plate are called the _________
Spaces of Disse (AKA perisinusoidal spaces)
What do Kupffer cells do?
Kupffer Cells are resident macrophages that line the sinusoid and are capable of rapidly phagocytizing bacteria and other foreign invaders
What % of bacteria entering circulation from the intestine makes it past the Kupffer army and into systemic circulation?
Less than 1%
The portal vein runs _____ the liver while the hepatic veins _____ the liver
Enters, exits
The Hepatic Portal systems’ main function is to
drain blood from the GI tract and takes blood to the liver for further absorption and processing of material.
Trace the path of oxygenated blood from the aorta to the liver lobules
Abdominal Aorta > Celiac trunk > Hepatic Artery > right and left hepatic arteries > hepatic arterioles > liver lobules
Function of the hepatic vein
Draining deoxygenated venous blood and cleansed portal blood from the liver.
All central veins drain into the ____
Hepatic vein
Most common cause of portal hypertension
Cirrhosis of the liver: damage to the liver to which the architecture (hepatocytes) of the liver is lost and disrupts the flow of blood through the portal vein.
Portal hypertension is characterizes as an ______ in Portal Vein
Increase in intravascular pressure
Portal hypertension can result in
(ASCE)
Ascites
Splenic Engorgement
Caput Medusae: recanalization of the paraumbilical veins
Esophageal Varices: Dilated submucosal veins in the lower third of the esophagus
Liver functions in carbohydrate metabolism (3 things)
Storage of large amounts of glycogen (chains of glucose)
Conversion of galactose and fructose to glucose
Gluconeogenesis (making glucose from fats or proteins)
The liver plays an especially important role in maintaining a normal blood _____ concentration
glucose
An excess of blood glucose triggers _____ within the liver
Glycogenesis
The breakdown of glycogen into glucose is called
Glycogenolysis
If both blood glucose and liver glycogen stores are low, what process must occur?
Gluconeogenesis: conversion of certain amino acids or glycerol from triglycerides into glucose.
What functions does the liver have in fat metabolism?
Oxidation of fatty acids
Synthesis of cholesterol, phospholipids, and most lipoproteins
Synthesis of fats from proteins and carbohydrates
Fats initially bypass the liver by _____
Lymphatic drainage (via chylomicrons)
______ hydrolyzes triglycerides
Lipoprotein Lipase
By what process can the liver can split free fatty acids into compounds that form Acetyl Coenzyme A (Acetyl-CoA).
Beta-Oxidation
________ is the process by which excess proteins or carbohydrates are synthesized into fat for storage in adipose tissue
Lipogenesis
____ and ____ are synthesized by the hepatocytes
Bile and phospholipids
In order for the absorbed amino acids to be used for energy or converted into fats or carbohydrates, this process must occur
Deamination: This is when an amine group is removed from an amino acid, creating Ammonia (NH3).
Hepatic Encephalopathy in liver disease can be caused by high levels of
Ammonia
_______ is the process that creates Ammonia
Deamination
To get rid of Ammonia, the liver must convert it to _____ to be excreted in the kidneys
Urea (via urea cycle)
hypoalbuminemia can occur in liver failure and results in
Edema and contribute to ascites
Main plasma protein synthesized by the liver
Albumin (Additionally thrombopoietin and angiotensinogen)
The so-called Non-Essential amino acids can all be synthesized by the liver through a process called _____
Transamination
Important markers (transaminase enzymes) for liver injury
Alanine Transaminase (ALT)
Aspartate Transaminase (AST)
The vitamin stored in the greatest quantity in the liver is ______
Vitamin A
Apoferritin is a universal intracellular protein in hepatocytes that has the ability to store ____
Iron
Serum _____ lab test can be used in the diagnosis of iron deficiency anemia
Ferritin
T/F - coagulation factors and other proteins necessary for coagulation and hemostasis are made in the liver
True
Which coagulation factors are produced by Vitamin K?
Factors II, VII, IX, and X
We obtain Vitamin K from dietary intake of _____
green, leafy vegetables.
Whether due to Vitamin K deficiency, liver disease, or both, these two things occur
Increased risk of hemorrhage
Prevents effective hemostasis
In patients with severe liver disease, thyroxine and steroid hormones can accumulate in large emounts, potentially causing ____ in men
Gynecomastia
A large percentage of prescribed pharmacologic drugs are metabolized in the liver by _____
Cytochrome P450 enzymes.
Bilirubin is an end product of what process
hemoglobin degradation
Lifespan of redblood cells
120 days
Path of RBCs to Bilirubin
Fragile RBCs rupture in circulation > free hemoglobin taken up by tissue macrophages > heme oxygenase converts heme to biliverdin > reduction of biliverdin to unconjugated bilirubin > conjugated in liver to become bilirubin
How is unconjugated bilirubin taken up by the hepatocytes?
Quickly binds with albumin and is taken up by Hepatocytes via Facilitated Diffusion
Conjugated Bilirubin is excreted by _____ Transport into the Bile
Active Transport
______ in the intestine converts about half of Bilirubin into Urobilinogen
Bacterial action
T/F - a large portion of Urobilinogen is reabsorbed into the Hepatic Portal System
T
Jaundice occurs as a result of accumulation of large quantities of _____ in the extracellular fluids because of high blood levels and can be ___ or ____
Bilirubin; conjugated or unconjugated
Two types of Jaundice
Hemolytic anemias result in rapid release of bilirubin into the blood.
Liver disease or a downstream hepatobiliary obstruction can result in the inability to excrete even a normal amount of bilirubin
What is “direct” bilirubin? “indirect”?
Direct: conjugated
Indirect: Unconjugated
Hemolytic jaundice results in large amounts of serum _____ bilirubin
unconjugated
liver disease and obstructive jaundice result in high levels of serum _____ bilirubin
conjugated
These cells line the sinusoid and phagocytize bacteria and other foreign invaders in the liver
Kupffer Cells
Ascites is a result of _____ (portal HTN) and ______ (low serum albumin from liver disease)
Increased hydrostatic pressure; decreased oncotic pressure
