Cell Injury and Inflammation Lecture Quiz
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Questions and Answers

What term describes the increase in cell size?

  • Hypertrophy (correct)
  • Metaplasia
  • Hyperplasia
  • Atrophy

    • Which adaptive response involves an increase in cell number?

  • Hyperplasia (correct)
  • Atrophy
  • Hypertrophy
  • Metaplasia

    • Which process is a type of cellular adaptation to increased workload?

  • Homeostasis
  • Atrophy
  • Hypertrophy (correct)
  • Cellular Injury

    • What happens if the adaptive capability of a cell is exceeded?

    <p>Cellular Injury</p> Signup and view all the answers

    Which term describes a decrease in cell size?

    <p>Atrophy</p> Signup and view all the answers

    What is the primary goal of cellular adaptation?

    <p>To preserve viability and function</p> Signup and view all the answers

    Which of the following is NOT a principal adaptive response?

    <p>Necrosis</p> Signup and view all the answers

    What does metaplasia refer to in cellular adaptation?

    <p>Change in cell type</p> Signup and view all the answers

    What is a consequence of protracted drug use that leads to adaptation in the body?

    <p>Increased SER</p> Signup and view all the answers

    Which cellular structure is primarily responsible for maintaining cell shape and providing mechanical strength?

    <p>Cytoskeleton</p> Signup and view all the answers

    What happens when ATP-dependent calcium transporters fail?

    <p>Increased cytosolic calcium</p> Signup and view all the answers

    In what way can drugs that bind to microtubules affect cell proliferation?

    <p>They prevent cell proliferation</p> Signup and view all the answers

    What role do reactive oxygen species (ROS) play in cellular signaling?

    <p>They serve as physiological second messengers</p> Signup and view all the answers

    What is one potential source of oxidative stress in cells?

    <p>NADPH oxidases</p> Signup and view all the answers

    Which factor is NOT a mechanism of cellular injury?

    <p>Hormonal fluctuations</p> Signup and view all the answers

    What is one of the changes that occurs in mitochondria due to exercise?

    <p>Increase in mitochondrial number</p> Signup and view all the answers

    What is a characteristic feature of reversible cellular injury?

    <p>Fatty change (steatosis)</p> Signup and view all the answers

    Which process involves the lysosomal digestion of a cell's own components?

    <p>Autophagy</p> Signup and view all the answers

    What is indicated by the presence of myelin figures in necrosis?

    <p>Degradation of cellular components</p> Signup and view all the answers

    What occurs due to the induction of smooth endoplasmic reticulum in response to stress?

    <p>Enhanced detoxification of drugs</p> Signup and view all the answers

    Which nuclear change is characterized by the fragmentation of the nucleus?

    <p>Karyorrhexis</p> Signup and view all the answers

    What is a common characteristic of necrotic cells as seen in histological sections?

    <p>Increased pink staining with H&amp;E</p> Signup and view all the answers

    Which of the following represents a typical subcellular response to injury?

    <p>Hypertrophy of smooth ER</p> Signup and view all the answers

    What can lead to cellular swelling?

    <p>Failure of ATP-dependent ion pumps</p> Signup and view all the answers

    What is compensatory hyperplasia primarily stimulated by?

    <p>Growth factors from remnant hepatocytes</p> Signup and view all the answers

    What condition is characterized by the overgrowth of endometrial tissue due to hormonal imbalance?

    <p>Endometrial hyperplasia</p> Signup and view all the answers

    Which of the following is a possible physiologic cause of atrophy?

    <p>Loss of endocrine stimulation</p> Signup and view all the answers

    Metaplasia is best described as what type of cellular adaptation?

    <p>Reversible change of one adult cell type to another</p> Signup and view all the answers

    What happens when hormonal or growth factor stimulation abates in hyperplastic processes?

    <p>Hyperplasia disappears</p> Signup and view all the answers

    Which adaptation process involves an increase in cell size due to increased workload or stress?

    <p>Hypertrophy</p> Signup and view all the answers

    What is characteristic of apoptotic cell death compared to necrosis?

    <p>Involves fragmentation of cells</p> Signup and view all the answers

    What is the most common cause of hypoxia affecting cellular respiration?

    <p>Ischemia</p> Signup and view all the answers

    Which type of adaptation would likely result in the replacement of respiratory epithelial cells in habitual smokers?

    <p>Metaplasia</p> Signup and view all the answers

    What type of cell injury results from a deficit in oxygen supply affecting oxidative phosphorylation?

    <p>Necrosis</p> Signup and view all the answers

    Study Notes

    Cell Injury, Inflammation, and Repair (3 lecture hours)

    • Recommended Reading: Robbins Basic Pathology, 10th Edition (2018)

    Cell Injury

    • Learning Objectives:
      • Understand the underlying principles of cell injury.
      • Define and describe cell injury-related concepts: homeostasis, adaptation, hypertrophy, hyperplasia, atrophy, metaplasia.
      • Detail all possible mechanisms of cell injury.
      • Describe morphological changes associated with cell injury.

    Homeostasis

    • Definition: The stable internal environment of cells, tightly regulated to maintain a constant state.

    • Intracellular Milieu:

      • Concentration of anions and cations
      • Concentration of enzymes
      • Enzymatic activity
      • Concentration of various proteins
      • pH of cytosol and cell organelles

    Cellular Adaptation

    • Purpose: Preserve cell viability and function when encountering stress (physiological or pathological).

    • Stress Types: Physiological stress (increased workload) or pathological stress (nutrient deprivation, injuries).

    • Cellular Injury: Occurs if the adaptive capacity is exceeded.

    Cellular Injury Progression

    • Normal Cell (Homeostasis) → Injurious Stimulus → Reversible Injury (mild) → Severe, Progressive Injury (Severe) →Irreversible Injury → Cell Death:
      • Irreversible injury leads to two paths: necrosis or apoptosis

    Overview: Adaptive Responses

    • Hypertrophy: Increase in cell size (e.g., striated muscle cells).
    • Hyperplasia: Increase in cell number (e.g., glandular epithelium in the female breast).
    • Atrophy: Decrease in cell size (e.g., due to loss of innervation, decreased workload, or reduced blood supply ).
    • Metaplasia: Change in cell type (e.g., squamous epithelium in respiratory tract of smokers).

    Hypertrophy

    • Mechanism: Enlargement of existing cells by increasing structural proteins and organelles.
    • Examples: Physiological (exercise, pregnancy), pathological (hypertension, myocardial infarction).

    Hyperplasia

    • Conditions where cells can replicate: Smooth muscle cells a. Physiologic: Stimulated by hormones (e.g., female breast during puberty/pregnancy), response to removal of tissue part. b. Pathologic: Caused by excess hormones or growth factors (e.g., endometrial hyperplasia).

    Atrophy

    • Causes
      • Pathologic: Loss of innervation, decreased workload, reduced blood supply, inadequate nutrition
      • Physiologic: Reduced endocrine stimulation (e.g., menopause) or aging (senile atrophy)

    Metaplasia

    • Definition: Reversible change where one cell type is replaced by another type, better suited to the adverse environment.
    • Example: Replacement of columnar epithelium by squamous epithelium in the trachea/bronchi of smokers.
    • Important protective mechanisms are lost (e.g., mucus secretion, cilia).

    Cell Death

    • Overview: Cells die via two major paths:
      • Necrosis
      • Apoptosis

    Necrosis

    • Characteristics:
      • Cellular swelling
      • Nuclear swelling & lysis
      • Death of many cells
      • Lysosome breakdown
      • Inflammation
      • Calcification
      • Cessation of protein synthesis
      • Energy-independent

    Apoptosis

    • Characteristics:
      • Cellular shrinkage
      • Chromatin condensation and fragmentation (apoptotic bodies)
      • Death of single cells
      • Lysosomes intact
      • No inflammation
      • No calcification
      • Requires protein synthesis
      • Energy-dependent
    • Phagocytosis of apoptotic bodies which prevents inflammation.

    Mechanisms of Cell Injury

    • Oxygen Deprivation: Interruption of oxidative phosphorylation. Common cause is ischemia.
    • Chemical Agents: Reactive oxygen species (ROS)
    • Infectious Agents: Viruses, bacteria, fungi
    • Immunologic Reactions: Autoimmune and allergic reactions
    • Genetic Defects: Deficiency of functional proteins
    • Physical Agents: Trauma, radiation, extreme temperatures

    Reversible Cellular Injury Morphology

    • Cellular Swelling: Failure of ATP-dependent ion pumps, loss of ionic and fluid homeostasis.
    • Fatty Change (Steatosis): Appearance of lipid-filled vacuoles in cytoplasm. Impairment in lipid metabolism.

    Necrosis Morphology

    • Increased eosinophilia: Increased pink staining with H&E due to less RNA and increased protein denaturation
    • Myelin Figures: Structural characteristics.
    • Calcification: Mineral deposition in cells/tissues.
    • Nuclear Changes: Karyolysis, pyknosis, karyorrhexis

    Autophagy and Autophagy

    • Definition: Lysosomal digestion of the cell's own components (i.e., cellular components). Can be considered a survival mechanism during nutrient deprivation.
    • Residual Bodies:
      • contain undigested debris.
      • contain pigmentation (e.g ink)

    Induction (Hypertrophy) of Smooth ER

    • Mechanism: Related to drug metabolism by the P450 enzyme system in the liver.
    • Consequence: Protracted drug use leads to smooth ER adaptation (increase in size), and the need to increase the dose of the drug.

    Mitochondrial Alterations

    • Changes in size, shape, and number
    • Constant fusion and fission. Exercise, for instance, increases mitochondrial numbers.

    Cytoskeletal Abnormalities

    • Cytoskeleton: A protein fiber array that provides cell shape, structural support, facilitates separation of chromosomes, and plays an important role in maintaining cell integrity.
    • Types:
      • Microtubules
      • Actin filaments
      • Intermediate filaments
    • Cells constantly remodel their intracellular scaffolding in response to environmental stresses..
    • Membrane stability depends on cytoskeleton. Drugs like anticancer drugs bind to microtubules and prevent proliferation.

    Mechanism of Cell Injury Overview

    • Injury stimulus → Damage to various cellular components (e.g., ATP depletion, membrane damage, cytoskeletal damage, DNA damage, protein misfolding). → Multiple downstream effects → Cell death (necrosis or apoptosis).

    ATP Depletion

    • Cause: Lack of oxygen/nutrients, direct mitochondrial damage, toxins (e.g. cyanide).
    • Effects:
      • Decreased ionic pump activity in cell → osmotic gain of water → cellular swelling
    • Consequences
    • Increased intracellular calcium levels
    • Mitochondrial damage (loss of ATP)
    • Increased formation of ROS
    • Protein misfolding/degradation

    Increased Cytosolic Calcium

    • Cause: Failure of ATP-dependent calcium transporters.
    • Effects: Leads to enzyme activation, potentially damaging proteins and organelles.

    • ROS (Reactive Oxygen Species), generated during incomplete oxygen reduction.

    • Sources of ROS:

    • NO synthase, xanthine oxidase, NADPH oxidases, mitochondria

    • Consequences: ROS damage organelles/structure, and cellular components (lipids, proteins, and DNA), leading to cellular injury & death.

    • Removal of ROS: antioxidant mechanisms (SOD, catalase).

    ROS Paradigm Shift

    • ROS are not always harmful, but can be physiological 2nd messengers (example is hydrogen peroxide) for different biochemical pathways.
    • Pathologic excess comes from unregulated ROS product over response to hypoxia/stress.

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    Cell Injury, Inflammation & Repair (PHIDG 1501 Lecture Notes) PDF

    Description

    Test your knowledge on cell injury, inflammation, and repair as discussed in Robbins Basic Pathology. This quiz covers key concepts including homeostasis, cellular adaptation, and mechanisms of cell injury. Ensure you understand the principles and morphological changes associated with these conditions.

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