Disease Classification Overview

Disease Classification

• Diseases are broadly categorized based on factors like etiology (cause), pathogenesis (development), and clinical presentation.
• Infectious diseases are caused by pathogens like bacteria, viruses, fungi, or parasites.
• Non-infectious diseases arise from genetic predisposition, environmental exposure, or lifestyle choices. Examples include cancer, cardiovascular disease, and diabetes.
• Congenital diseases are present at birth, often due to genetic abnormalities or environmental influences during gestation.
• Degenerative diseases involve progressive tissue or organ deterioration, such as Alzheimer's disease.
• Mental illnesses affect thoughts, emotions, and behaviors; categorized by symptoms and characteristics.
• Chronic diseases are long-lasting, needing ongoing management.
• Acute diseases have rapid onset with intense symptoms, and short duration.

Pathology Basics

• Pathology studies disease through structural and functional changes in tissues and organs.

• Pathologists use microscopy, immunohistochemistry, and molecular biology for disease diagnosis and understanding.

• Cellular changes are often central to disease pathology.

• Atrophy is decreased cell size and function.

• Hypertrophy is increased cell size and function.

• Hyperplasia means increased cell number.

• Dysplasia shows abnormal cell size, shape, and organization.

• Metaplasia is a reversible cell type replacement.

• Neoplasia (tumor formation) involves uncontrolled growth, potentially leading to malignant tumors.

• Inflammation is a protective body response; prolonged or severe inflammation can damage tissues. Inflammation recruits immune cells and releases inflammatory mediators.

• Apoptosis (programmed cell death) is crucial for normal tissue development and maintenance.

• Necrosis is premature cell death due to injury (e.g., pathogens, toxins, trauma), often causing inflammation.

• Cellular injury sources include:

  • Hypoxia: Reduced oxygen supply.
  • Ischemia: Reduced blood flow.
  • Physical agents: Trauma, heat, radiation.
  • Chemical agents: Poisons, toxins, heavy metals.
  • Infectious agents: Viruses, bacteria, fungi, parasites.
  • Immunologic reactions: Autoimmune diseases, allergies.
  • Nutritional imbalances: Nutrient deficiencies or excesses.

• Cellular adaptations are reversible adjustments to stress, allowing survival but potentially compromising function.

• Cellular accumulations happen when cells cannot digest or remove substances, e.g., lipid accumulation.

• Cellular aging is the normal, natural decline in cellular function throughout a lifespan.

Explore the various classifications of diseases based on etiology, pathogenesis, and clinical presentation. This quiz covers infectious, non-infectious, congenital, degenerative, mental illnesses, and chronic diseases. Test your knowledge on the factors that contribute to these health conditions.