Untitled Quiz

Study Notes

Inflammation is a protective response intended to eliminate the cause of cell injury, infectious agents, and necrotic cells, and to initiate repair.
Components of inflammation include blood vessels, white blood cells and platelets, plasma proteins and chemical mediators (coagulation/fibrinolytic system, kinin system, complement system), and extracellular matrix and stromal cells (structural fibrous proteins, adhesive glycoproteins, proteoglycans, basement membrane).
The immune response plays a crucial role in inflammation, with macrophages functioning in the elimination of microbes and dead tissue, along with mediators like cytokines and nitric oxide.

Vascular Changes: Alterations in blood vessel caliber lead to vasodilation and increased blood flow. Changes in vasculature also permit plasma proteins to leave circulation (increased permeability).
Cellular Events: Leukocytes emigrate from the microcirculation and accumulate in the focus of injury.

Leads to protein-rich fluid and cells entering extravascular tissues.
Increases osmotic pressure, causing more fluid to flow out of the blood into tissues, producing edema.

Transudate: Mechanism: hydrostatic pressure imbalance across vascular endothelium; fluid content is low in protein (ultrafiltrate of blood plasma). Typical in noninflammatory conditions.
Exudate: Mechanism: alteration in normal permeability of small blood vessels in area of injury; fluid content is high in protein. Typical in inflammatory conditions.

Acute Inflammation: Fast onset (minutes to hours), short duration (minutes to days), characterized by mainly neutrophils, usually mild and self-limiting tissue injury, and fibrosis.
Chronic Inflammation: Slow onset (days to years), long duration, with infiltrates of monocytes/macrophages and lymphocytes, often severe and progressive tissue injury and fibrosis.

Serous: Exudation of cell-poor fluid into spaces created by injury to surface epithelia or into body cavities (e.g., skin blisters).
Fibrinous: Consequence of more severe injuries, resulting in greater vascular permeability that allows large molecules (such as fibrinogen) to pass the endothelium.
Suppurative (Purulent): Collection of large amounts of pus (an exudate consisting of many neutrophils, debris of necrotic cells, and edema fluid).
Ulcer: Local defect of the surface of an organ or tissue that is produced by sloughing (shedding) of inflamed necrotic tissue.

Inflammation of prolonged duration (weeks to years)
Characterized by infiltration with mononuclear cells (macrophages, lymphocytes, plasma cells), tissue destruction, and repair.

Macrophages: Dominant cells of chronic inflammation, involved in phagocytosis.
B and T Lymphocytes: Important in cell-mediated immunity.
Mast cells: Source of histamine in allergic reactions.

Regeneration: Replacement of damaged cells by similar parenchymal cells, returning to a normal state. Typical in rapidly dividing epithelia (skin, intestines). Requires intact connective tissue.
Scar Formation: Occurs when tissues are incapable of regeneration or supporting structures are severely damaged. Connective tissue is laid down.

The immune system protects against microorganisms and removes damaged/cancerous cells.
Innate immunity: immediate, nonspecific protection (skin, mucous membranes).
Adaptive immunity: takes 7-10 days to develop, specific to the antigen (cellular or humoral).
T-cells: destroy antigen.
B-cells: produce antibodies.

Hypersensitivity: Inappropriate immune response to an antigen, leading to inflammation and destruction of healthy tissue. This includes four subtypes: type I (IgE-mediated), type II (cytotoxic), type III (immune complex-mediated), and type IV (cell-mediated).
Autoimmune disorders: Normal defenses recognize self as foreign, leading to destruction of the body's own tissues. Examples: systemic lupus erythematosus, rheumatoid arthritis.
Immunodeficiency: Diminished or absent immune response, increasing susceptibility to infections. Can be primary (genetic defect) or secondary (underlying disease, malnutrition, drugs).