Cell Injury and Death Overview

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

Which of the following is NOT a common cause of cell injury?

Physical agents

Psychological stress (correct)

Chemical agents

Inadequate oxygenation

What is the characteristic feature of reversible cell injury that involves the accumulation of water in the cytoplasm?

Hydropic change (correct)

Fatty change

Necrosis

Apoptosis

Which of the following is a characteristic feature of irreversible cell injury?

Increased ATP production

Reduced membrane permeability

Restoration of normal cellular function

Mitochondrial swelling (correct)

What is the term for a localized area of ischemic necrosis in an organ?

Infarct (A) Signup and view all the answers

Which of the following is NOT associated with the process of apoptosis?

Inflammatory response (B) Signup and view all the answers

Which of the following is a physiological example of apoptosis?

Removal of excess cells during development (C) Signup and view all the answers

Which of the following is NOT a characteristic of necrosis?

Programmed cell death (A) Signup and view all the answers

What is the term for the accumulation of lipids, specifically triglycerides, in the cytoplasm of cells?

Steatosis (A) Signup and view all the answers

Which type of cell adaptation involves an increase in the size of cells, leading to an increase in organ size?

Hypertrophy (C) Signup and view all the answers

Which type of cell adaptation involves a reversible change from one adult cell type to another?

Metaplasia (D) Signup and view all the answers

Which of the following is a hallmark of oxidative stress?

Damage to cellular components like lipids, proteins, and DNA (A) Signup and view all the answers

How does ATP depletion contribute to cell injury?

Reduced protein synthesis (C) Signup and view all the answers

What is a possible consequence of a prolonged unfolded protein response (UPR)?

Apoptosis (B) Signup and view all the answers

Which of the following is a major contributor to the pathogenesis of ischemic reperfusion injury?

Increased calcium levels in the cytoplasm (B) Signup and view all the answers

Which of these is NOT an example of a type of cell death?

Metaplasia (A) Signup and view all the answers

What is the main function of the BCL-2 protein family in the mitochondrial pathway of apoptosis?

To regulate mitochondrial permeability (C) Signup and view all the answers

Study Notes

Cell Injury and Death

Adaptation: Cells respond to stressors by adapting, undergoing injury, or death.
Reversible injury: Characterized by generalized cellular swelling (hydropic change) and fatty change, but fully reversible if stressor removed.
Irreversible injury:
- Inability to recover from mitochondrial dysfunction (lack of oxidative phosphorylation + ATP production) and profound membrane disturbances.
- Occurs after ischemic insult in most organs except the brain.
Types of Necrosis:
- Coagulative necrosis: Architecture preserved for a while, firm texture. Occurs in most organs (except brain) after ischemia.
- Liquefactive necrosis: Digestion of dead cells, creamy yellow appearance. Seen in brain ischemia and focal bacterial/fungal infections.
- Caseous necrosis: Granulomatous appearance under microscope, fragmented cells enclosed in inflammation border.
- Fat necrosis: Chalky white areas (saponification) due to pancreatic enzymes. Occurs in acute pancreatitis.
- Fibrinoid necrosis: Complexes of antigens and antibodies in vessel walls; bright pink and amorphous on H&E stains.
Apoptosis: Programmed cell death, tightly regulated, no inflammation.
- Physiologic: removal of excess cells in development, involution of hormone-dependent tissues, elimination of self-reactive lymphocytes.
- Pathologic: DNA damage, accumulation of misfolded proteins, viral infections.
- Morphology: Cell shrinkage, chromatin condensation, cytoplasmic blebs, apoptotic bodies (phagocytosed).
- Pathways: Mitochondrial (intrinsic) and death receptor (extrinsic); both converge on caspase activation.
Necroptosis: Necrosis-like cell death, triggered by excess iron or reactive oxygen species (ROS), looks like necrosis but regulated. Involves kinases RIPK1 and RIPK3.

Cellular Aging

Cells have a limited capacity for replication, leading to cellular senescence.
Telomere shortening, DNA damage, defective protein homeostasis, nutrient sensing, and insulin/IGF signaling contribute to cellular aging.
Cellular senescent cells produce factors that induce inflammation and contribute to tissue dysfunction.

Pathologic Calcification

Dystrophic calcification: Deposition of calcium salts in dying tissue despite normal serum calcium levels.
Metastatic calcification: Deposition of calcium salts in normal tissues due to hypercalcemia (elevated blood calcium).
- Causes: parathyroid hormone (PTH) overactivity, vitamin D-related disorders, renal failure, hemochromatosis.

Other Cellular Damage

Hypoxia/ischemia: Inadequate oxygenation of blood; often worse than hypoxia due to metabolite buildup. Key factor is hypoxia-inducible factor 1 (HIF-1) activation.
Chemical injury: Direct binding to important molecules or conversion to toxic metabolites.
Oxidative stress: ROS's (oxygen-derived free radicals) damage lipids, proteins, and nucleic acids that leads to cell injury.
Calcium homeostasis disturbances: Excessive intracellular calcium activates enzymes that damage cellular components.
Endoplasmic reticulum stress: Accumulation of misfolded proteins triggers apoptosis or cellular dysfunction.

Adaptations

Hypertrophy: Increase in cell size (physiological or pathological, e.g., cardiac hypertrophy).
Hyperplasia: Increase in cell number (physiological or pathological, e.g., benign prostatic hyperplasia).
Atrophy: Decrease in cell size and number (e.g., reduced blood supply, inadequate nutrition, loss of endocrine stimulation).
Metaplasia: Change in cell type, sometimes associated with increased cancer risk.
Intracellular accumulations: Abnormal accumulation of substances like lipids, proteins, or pigments, e.g., fatty change.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

This quiz focuses on the concepts of cell injury and death, including adaptation, reversible and irreversible injuries, and types of necrosis. Participants will learn about the mechanisms and characteristics of various necrotic processes in different organs. Test your understanding of these critical cellular responses in pathology.