BHSC 401
Pathophysiology
Foundations of Disease Processes
Basic Health Sciences (BHSC) Program
Academic Year 2024–2025
, 1. Introduction to Pathophysiology
Pathophysiology is the study of how normal physiological processes are disrupted by
disease. It bridges basic science and clinical medicine, providing the mechanistic
foundation for understanding signs, symptoms, diagnosis, and treatment.
Key Terms Pathology: study of disease | Etiology: cause of disease | Pathogenesis:
mechanism of disease development | Manifestation: signs and symptoms |
Prognosis: predicted outcome
2. Cellular Responses to Injury
2.1 Causes of Cell Injury
• Hypoxia/ischemia: most common cause; oxygen deprivation
• Physical agents: trauma, temperature extremes, radiation
• Chemical agents: toxins, drugs, reactive oxygen species
• Infectious agents: viruses, bacteria, fungi, parasites
• Immunological reactions: autoimmune disease, hypersensitivity
• Genetic defects: enzyme deficiencies, structural protein abnormalities
• Nutritional imbalances: deficiencies or excesses
2.2 Reversible Cell Injury
Cells that can recover if the injurious stimulus is removed:
• Cellular swelling: Na+/K+ pump failure; water influx
• Fatty change (steatosis): lipid accumulation in hepatocytes
• Reduced ATP production; ribosome detachment; decreased protein synthesis
2.3 Irreversible Cell Injury & Cell Death
Necrosis (pathological cell death):
• Coagulative necrosis: most common; ischemia; cell outline preserved initially
(e.g., MI)
• Liquefactive necrosis: bacterial infections and brain infarcts; cell contents liquefy
• Caseous necrosis: tuberculosis; cheese-like amorphous debris
Pathophysiology
Foundations of Disease Processes
Basic Health Sciences (BHSC) Program
Academic Year 2024–2025
, 1. Introduction to Pathophysiology
Pathophysiology is the study of how normal physiological processes are disrupted by
disease. It bridges basic science and clinical medicine, providing the mechanistic
foundation for understanding signs, symptoms, diagnosis, and treatment.
Key Terms Pathology: study of disease | Etiology: cause of disease | Pathogenesis:
mechanism of disease development | Manifestation: signs and symptoms |
Prognosis: predicted outcome
2. Cellular Responses to Injury
2.1 Causes of Cell Injury
• Hypoxia/ischemia: most common cause; oxygen deprivation
• Physical agents: trauma, temperature extremes, radiation
• Chemical agents: toxins, drugs, reactive oxygen species
• Infectious agents: viruses, bacteria, fungi, parasites
• Immunological reactions: autoimmune disease, hypersensitivity
• Genetic defects: enzyme deficiencies, structural protein abnormalities
• Nutritional imbalances: deficiencies or excesses
2.2 Reversible Cell Injury
Cells that can recover if the injurious stimulus is removed:
• Cellular swelling: Na+/K+ pump failure; water influx
• Fatty change (steatosis): lipid accumulation in hepatocytes
• Reduced ATP production; ribosome detachment; decreased protein synthesis
2.3 Irreversible Cell Injury & Cell Death
Necrosis (pathological cell death):
• Coagulative necrosis: most common; ischemia; cell outline preserved initially
(e.g., MI)
• Liquefactive necrosis: bacterial infections and brain infarcts; cell contents liquefy
• Caseous necrosis: tuberculosis; cheese-like amorphous debris
