Histo path

• Inflammation


  19-02-2024
• Inflammation


  The response reaction of tissue to injury that is characterized by vascular changes and cellular response, which work together to get rid of the injurious agent and heal the tissue, returning its functionality
• Aims of inflammation


  • To localize the injurious agent
  • To heal the tissue and bring back its functionality
  • Locating and eliminating the injurious agent and removing damaged tissue components
• Disadvantages of inflammation


  • Inflammation can cause tissue destruction when the regulatory mechanism of inflammation is defective or inability to clear damaged tissue
  • An appropriate immunological response may cause prolonged and damaging inflammatory responses such as allergic reactions and autoimmune diseases
• Cardinal signs of inflammation

  • Redness (rubor)
  • Heat (calor)
  • Pain (dolor)
  • Tumor/edema (swelling)
  • Loss of function
• Classes of inflammation


  • Acute inflammation
  • Chronic inflammation
• Acute inflammation


  • The early response of the body or tissue to an injury or injurious agent, and the first line of defense against the injurious agent, which begins to cease once the injurious agent has been removed
  • It lasts for minutes, hours and few days
• Components of acute inflammation

  • Vasodilation
  • Increased vascular permeability
  • Exudation
  • Chemotaxis
  • Phagocytosis
• Exudates


  Fluids found in the interstitial space as a result of inflammation, with high protein content (up to 2-3 g/dl) and specific gravity of 7/1901
• Cells involved in acute inflammation

  • Polymorphonuclear neutrophils
  • Eosinophils
  • Monocytes
  • Basophils
• Chronic inflammation


  • Inflammation that sets in when the acute inflammatory responses failed or did not resolve the tissue damage, lasting for months and years
  • It could also result from the ability of injurious material or pathogen to resist the inflammatory responses, or from inappropriate immune responses like autoimmune diseases and hypersensitivity reactions
• Hallmarks of chronic inflammation

  • Infiltration of tissue sites by macrophages, lymphocytes, plasma cells and fibroblasts
• Lab diagnosis for inflammation

  • Erythrocyte Sedimentation Rate (ESR)
  • C-Reactive Protein
• Cell


  Basic building unit of a larger form of life, capable of carrying out all basic functions of life
• Cell


  • Surrounded by a membrane
  • Contains a nucleus
  • Filled with a gelatinous fluid called cytoplasm
  • Composed of cytoplasmic organelles which are specialized in carrying out individual functions of the cell
• Tissues and organs


  Cells in the human body are grouped together to form
• Types of cells


  • Epithelial cells
  • Connective tissue cells
  • Myocytes (muscular tissue cells)
  • Nervous tissue cells
• Epithelial cells


  • Live on the surfaces of organs and cavities in the body
  • Perform protective, secretory, and sensory functions
  • Can be arranged to form glands
• Connective tissue cells


  • Connect tissues and form the shape of the body
  • Found in bone, cartilage, tendon, ligament
  • Include fibroblasts, leukocytes, mast cells, macrophages, adipocytes
  • Responsible for formation of connective tissue structures like collagen, elastic fibers, reticulin
• Connective tissue cells


  • Can assume epithelial cell appearance in abnormal conditions, e.g. squamous metaplasia
• Myocytes (muscular tissue cells)

  • Different types include skeletal, smooth, and cardiac muscles
  • Some are multinucleated, like skeletal muscle
  • Involved in muscle contractions
• Nervous tissue cells


  • Help in transmission and conduction of impulses
• Cellular adaptation to injury


  Ability of cells to respond to various stimuli and adverse environmental changes
• Agents that can cause cellular injury

  • Chemical agents and drugs
  • Genetic defects
  • Microbial agents
  • Physical agents
  • Nutritional imbalance
  • Aging
• Adaptive mechanisms or forms of adaptation

  • Atrophy
  • Hypertrophy
  • Hyperplasia
  • Metaplasia
• Atrophy


  Shrinkage or decrease in the size of a cell due to loss of cellular substance and organelles, resulting from decreased work, nerve supply, blood supply, nutrition, or hormonal stimulation
• Hypertrophy


  Increase in the size of individual cells resulting in increased mass of tissue without change in cell number, in response to increased demand for work and training
• Hyperplasia


  Increase in the number of cells, as a result of increased cell division, in response to increased physiologic workloads or stimulation
• Metaplasia


  Reversible change in which one cell type is replaced by another, to adapt to a hostile environment
• Metaplasia


  • Bronchial pseudostratified ciliated epithelial cells becoming stratified squamous epithelial cells in response to cigarette smoke
  • Normal esophageal squamous epithelial cells changing to columnar epithelial cells in Barrett's esophagus due to persistent acid reflux
• Apoptosis and necrosis are forms of cell death
• Barrett's esophagus is an abnormal condition in which the cells lining the lower portion of the esophagus change from normal squamous epithelial cells to columnar epithelial cells due to persistent acid reflux