Pathophysiology In-Depth Study Guide

Pathophysiology In-Depth Study Guide

Ischemia

  • Definition:

    • Ischemia is a reduction in blood flow to tissues.

    • It leads to decreased oxygen and nutrient delivery to cells.

  • Significance:

    • Cells rely on oxygen to produce ATP for normal function.

    • When oxygen supply drops, cells shift to anaerobic metabolism, causing lactic acid buildup and decreased energy production.

  • Causes of Ischemia:

    • Blocked arteries (e.g., atherosclerosis, clots)

    • Low blood pressure (e.g., shock)

    • Heart failure

    • Respiratory failure

  • Consequences:

    • Prolonged ischemia can lead to irreversible cell injury and necrosis.

Necrosis

  • Definition:

    • Necrosis refers to uncontrolled cell death caused by severe injury.

  • Causes of Necrosis:

    • Prolonged ischemia

    • Trauma

    • Infection

    • Toxins

    • Radiation

  • Characteristics of Necrosis:

    • Cell swelling

    • Membrane rupture

    • Leakage of cellular contents

    • Inflammatory response

  • Implications:

    • Necrosis damages surrounding tissues and delays healing processes.

Apoptosis

  • Definition:

    • Apoptosis is programmed cell death that occurs normally to maintain tissue health.

    • It serves to remove damaged or unwanted cells from the body.

  • Characteristics of Apoptosis:

    • Cell shrinkage

    • DNA fragmentation

    • Absence of inflammation

  • Significance:

    • Failure of apoptosis can allow abnormal cells to survive, contributing to cancer development.

Atrophy

  • Definition:

    • Atrophy is a decrease in cell size, and sometimes number, leading to overall tissue shrinkage.

  • Causes of Atrophy:

    • Disuse of tissue

    • Reduced blood supply

    • Aging

    • Malnutrition

  • Consequences:

    • Results in decreased tissue strength and function.

Anaphylactic Shock

  • Definition:

    • Anaphylactic shock is a severe allergic reaction.

  • Triggers:

    • Common allergens include foods, medications, insect stings, or latex.

  • Mechanism:

    • IgE antibodies trigger the release of histamine from mast cells, leading to:

    • Vasodilation → resulting in low blood pressure

    • Capillary leakage → causing swelling

    • Bronchoconstriction → leading to breathing difficulty

  • Immediate Treatment:

    • Epinephrine is required as immediate treatment.

Cancer Development

  • Stages of Cancer Development:

    • Initiation:

    • DNA mutation occurs.

    • Promotion:

    • Abnormal cell multiplication takes place.

    • Progression:

    • Malignant transformation and spread of cancer cells occur.

  • Cancer Staging:

    • Stage 0:

    • Localized in situ (at the site of origin).

    • Stage I:

    • Small localized tumor.

    • Stage II:

    • Larger tumor with limited spread.

    • Stage III:

    • Involvement of lymph nodes.

    • Stage IV:

    • Metastasis to distant organs takes place.

Connections Between Processes

  • Links:

    • Ischemia commonly leads to necrosis and inflammation.

    • Apoptosis normally prevents the survival of abnormal cells.

    • Failure of apoptosis contributes to cancer development.

    • Anaphylactic shock can cause ischemia through hypotension.