Liver Apoptosis and Injury Quiz

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Questions and Answers

What is associated with massive apoptosis in the liver?

Ischemic conditions and hypo perfusion (correct)

Increased bile acid synthesis

Chronic liver disease only

Neoplastic cell growth

Which pathway is linked to caspase-dependent apoptosis?

Both A and C (correct)

Extrinsic pathway

Intrinsic pathway

Necroptosis pathway

What triggers mitochondrial external membrane permeabilization during apoptosis?

Increase in TNF Alpha

Intrinsic signaling defects

Endoplasmic reticulum stress (correct)

Activation of death receptors

What is typically observed in hepatocytes during acute liver injury?

Massive apoptosis Signup and view all the answers

What can be seen in normal necrosis that is not characteristic of typical apoptosis?

Death receptor activation Signup and view all the answers

What role do smac/DIABLO and cytochrome C play in cell death?

They are involved in apoptosis induction. Signup and view all the answers

What type of liver disease is primarily associated with cytotoxic T cells?

Inflammatory liver diseases Signup and view all the answers

Which of the following statements about hepatocytes is false?

Normal hepatocytes can effectively undergo apoptosis. Signup and view all the answers

Which of the following triggers the release of profibrogenic cytokines in hepatocyte response to injury?

Hepatic stellate cell activation Signup and view all the answers

What is the primary difference between intrinsic and extrinsic apoptosis?

Intrinsic is primarily triggered by internal signals. Signup and view all the answers

What is a key consequence of massive apoptosis in liver tissue?

Inflammation and fibrogenesis Signup and view all the answers

What distinguishes reversible hepatocellular injury from irreversible injury?

Extent of ATP depletion Signup and view all the answers

Which of the following is a characteristic of reversible hepatocellular injury?

Mallory-Denk Bodies Signup and view all the answers

What cellular process is primarily responsible for repairing liver injury?

Regeneration of mature liver cells Signup and view all the answers

What is the primary difference between necrosis and apoptosis?

Apoptosis is a specific cascade; necrosis is unregulated cell death. Signup and view all the answers

Which condition is associated with microsteatosis?

HELLP syndrome Signup and view all the answers

What phenomenon is linked to ischemic-hypoxic injury in liver cells?

Increased oxidative stress Signup and view all the answers

What role do Kupffer cells play in apoptosis?

Phagocytosis of apoptotic bodies. Signup and view all the answers

What leads to necrosis during hepatocyte injury?

Increasing intracellular calcium levels Signup and view all the answers

Which pathway primarily induces apoptosis via death receptors?

Extrinsic pathway Signup and view all the answers

Which factor is essential for the survival and proliferation of mature liver cells?

Optimal portal blood flow Signup and view all the answers

What is a key feature of ballooning degeneration in hepatocellular injury?

Membrane volume control derangement Signup and view all the answers

Which factor is NOT typically associated with reversible hepatocellular injury?

Necroptosis Signup and view all the answers

Which of the following statements best describes necrosis?

Necrosis involves intracellular ATP depletion. Signup and view all the answers

What is the primary role of hepatocytes in relation to progenitor cells during chronic injury?

To signal that they cannot regenerate Signup and view all the answers

What effect does fibrosis have on hepatocyte remodeling?

Interferes with normal lobular arrangement Signup and view all the answers

Which of the following is NOT a type of collagen mentioned in relation to the liver's extracellular matrix?

Type IX Signup and view all the answers

What does the presence of c-kit indicate in the context of liver repair?

Active stem/progenitor cell processes Signup and view all the answers

Which of the following extracellular matrix components is categorized as non-fibrillary?

Laminin Signup and view all the answers

In the context of hepatic fibrogenesis, what does an increase/change in the extracellular matrix typically precede?

Microvascular rearrangement Signup and view all the answers

Which cellular marker indicates an active biliary proliferation during liver repair?

CK 7 Signup and view all the answers

What is a characteristic of the liver in a ‘streaming liver’ state following chronic injury?

Presence of fibrogenesis Signup and view all the answers

What triggers hepatocytes to enter the cell cycle in response to liver injury?

Cytokines secreted by Kupfer cells Signup and view all the answers

Which cell type is primarily responsible for secreting TNF-alpha during liver injury?

Kupfer cells Signup and view all the answers

In cases of chronic liver injury, what is the primary source of liver regeneration?

Proliferation of hepatic progenitor cells Signup and view all the answers

What is the significance of the G0 phase in hepatocytes?

It represents a stable state from which they can re-enter the cell cycle Signup and view all the answers

Which cytokine exclusively binds to hepatocyte receptors to stimulate regeneration?

Interleukin-6 Signup and view all the answers

What is a possible effect of telomere shortening in hepatocytes during liver regeneration?

Inhibition of hepatocyte proliferation Signup and view all the answers

Which factor is NOT directly involved in the liver regeneration process after acute injury?

Proliferation of stem cells Signup and view all the answers

What initial step occurs when Kupfer cells encounter apoptotic or necrotic cells?

Engulfment of dead cells Signup and view all the answers

What is the primary consequence of Ito cell activation during liver damage?

Obstruction of endothelial pores Signup and view all the answers

Which process occurs as a result of high sinusoidal pressure in liver damage?

Formation of porto-central shunts Signup and view all the answers

Which of the following statements is true regarding capillarization in liver disease?

It is associated with a decrease in endothelial permeability Signup and view all the answers

What is a key characteristic of porto-systemic shunts formed during portal hypertension?

They bypass normal portal circulation Signup and view all the answers

Which of the following is NOT a consequence of microvascular rearrangement in liver damage?

Decreased parenchymal loss lesions Signup and view all the answers

What role does chronic inflammation play in hepatic fibrogenesis?

It promotes the accumulation of HIF-1 in endothelial cells Signup and view all the answers

Nodulation in the liver can result from which underlying condition?

Chronic viral hepatitis Signup and view all the answers

What is one consequence of portal/vascular fibrosis in liver damage?

Development of pre-sinusoidal vascular resistance Signup and view all the answers

How does hypoxia influence the process of liver fibrosis?

It activates HSC and myofibroblast proliferation Signup and view all the answers

Which of the following best explains the relationship between vascular changes and ischemic injury in the liver?

Vascular changes increase risk of focal ischemic injury Signup and view all the answers

Study Notes

Morphologic Patterns of Hepatic Injury and Cirrhosis

The presentation is about the morphological patterns of hepatic injury and cirrhosis, focusing on regeneration and fibrogenesis.
The discussion revolves around reversible and irreversible hepatic injury.

Hepatocellular Injury

Reversible injury includes ballooning degeneration, Mallory-Denk bodies, and steatosis.
Irreversible injury includes apoptosis and necrosis.

Reversible Injury

Ballooning Degeneration: Characterized by intracellular calcium increase, water influx, and membrane volume control derangement leading to hepatocyte swelling. ATP depletion is a major factor.
Mallory-Denk Bodies: Result from abnormal protein accumulation within hepatocytes, potentially progressing from reversible to irreversible changes, often associated with keratin cytoskeleton alterations.
Steatosis: Fatty liver disease, characterized by fat accumulation within hepatocytes. Multiple causes exist, including viral hepatitis, autoimmune diseases, drugs, metabolic disorders, starvation, and total parenteral nutrition.

Irreversible Injury

Apoptosis: Programmed cell death with specific stimuli leading to a degradation cascade, characterized by chromatin condensation, DNA fragmentation, and cellular shrinkage.
Necrosis: Pathologic cell death due to metabolic degradation, typically involving intracellular calcium increase, ATP depletion, and cell swelling.
Oncotic Necrosis: A type of necrosis that results from swelling of the cells due to an inadequate supply of ATP.

Cell Death

Necrosis: Pathologic death characterized by cell membrane damage, swelling, and intracellular content leakage.
Apoptosis: Programme cell death. Apoptotic bodies form and are removed.
Necroptosis: A regulated form of necrosis.
Apoptosis is a form of programmed cell death.

Hepatic Repair

Regeneration: Liver repair involves mature liver cell proliferation and stem cell/progenitor cell proliferation and differentiation.
Fibrogenesis: Fibrosis occurs when collagen accumulates in the liver, impeding its normal function and structure.

Mechanisms of Hepatic Fibrosis

Inflammatory and fibrotic response triggered by apoptotic cells releasing ATP and UDP, stimulating macrophages and HSCs (hepatic stellate cells) . HSCs then release TGF-β, promoting fibrogenesis.
Fibrosis includes changes to ECM (extracellular matrix) density, profile, and distribution, with an increase in Type I and III collagen, as well as septa formation and lobular/sinusoidal collagen accumulation, causing dysfunction.
Inflammation, apoptosis, and reactive oxygen species contribute to hepatocyte injury and HSC activation, initiating fibrogenesis.
Active HSCs release profibrogenic cytokines, including TGF-β, promoting chronic liver injury and fibrosis.

Microvascular Rearrangement

Increase in endothelial permeability.
Formation of vascular shunts.
Vascular thrombosis and obstruction.
Capillarization of sinusoids.

Neovascularization

Chronic inflammation, hypoxia (low oxygen), and fibrosis stimulate angiogenesis (new blood vessel formation) in the liver.
Hepatocyte and Kupffer cell-derived cytokines, such as HIF-1, promote neoangiogenesis.

Portal/hepatic vein branch or sinusoidal obstruction

Portal or hepatic vein branch or sinusoidal obstruction leads to focal ischemic injury
Injured hepatocytes appear prior to the fibrotic septa.
Loss of parenchymal cells can occur.
Fibrosis development is observed in these areas.

Nodulation

Micronodular lesions (< 3mm) are often associated with alcoholic liver disease, metabolic disease, and venous outflow obstruction.
Macronodular lesions (> 3mm) are frequently related to viral hepatitis, autoimmune hepatitis, and other chronic liver conditions.

Additional Points

Specific cell types play crucial roles in liver fibrosis, including hepatic stellate cells, portal myofibroblasts, and endothelial cells.
The development of fibrosis and cirrhosis can be triggered by various factors, such as alcohol, viral infections, autoimmune diseases, and metabolic conditions.
The progression of liver damage can often lead to cirrhosis, characterized by widespread fibrosis, nodular regeneration, and architectural distortion, affecting liver function.

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Description

Test your knowledge on apoptosis mechanisms in liver cells. This quiz covers crucial aspects such as the pathways involved in caspase-dependent apoptosis, the role of mitochondrial membrane permeabilization, and the differences between reversible and irreversible hepatocellular injury. Perfect for students studying toxicology or liver physiology.