Overview
This lecture reviewed core concepts in pathophysiology, disease classification, cell injury, adaptation, neoplasia, and prevention, highlighting key differences and exam-relevant definitions.
Introduction to Pathophysiology
- Pathophysiology is the study of body functions in a diseased state.
- Anatomy studies structure; physiology studies normal function; pathophysiology studies function during disease.
- Etiology is the study of the cause or reason for a disease.
Disease Classifications & Risk Factors
- Diseases can be idiopathic (unknown cause), iatrogenic (from medical treatment), or infectious (caused by pathogens).
- Risk factors increase the chance of developing a disease but do not guarantee it.
Stages of Illness
- Latent (incubation) period: time between exposure and first symptoms.
- Prodromal stage: first signs or symptoms appear.
- Subclinical stage: disease present but without severe symptoms.
- Sign: observable manifestation; Symptom: subjective feeling by the patient.
Epidemiology & Levels of Prevention
- Epidemiology studies disease patterns in populations.
- Endemic: local region; epidemic: spreads to many people; pandemic: widespread/global.
- Primary prevention: reduces susceptibility (e.g., vaccinations, health campaigns).
- Secondary prevention: early detection/screening (e.g., mammograms).
- Tertiary prevention: rehabilitation and reducing disability (e.g., stroke therapy).
Homeostasis, Allostasis, and Stress Response
- Homeostasis: maintaining a stable internal environment.
- Allostasis: adaptive processes to maintain stability during stress.
- Allostatic overload: inability to adapt, leading to disease.
- General Adaptation Syndrome stages: alarm (fight/flight), resistance (coping), exhaustion (failure).
- Stress response involves the HPA axis, releasing CRH, ACTH, and cortisol.
Cellular Injury and Adaptation
- Reversible injuries: hydropic swelling (water in cells due to pump failure), intracellular accumulations (excess substances).
- Atrophy: cell size decreases; hypertrophy: cell size increases; hyperplasia: cell number increases.
- Metaplasia: one cell type converts to another; dysplasia: disordered, pre-cancerous growth.
Cell Death Mechanisms
- Apoptosis: programmed, regulated cell death.
- Necrosis: unregulated cell death due to ischemia (lack of blood flow) or toxins.
- Types of necrosis: coagulative (heart), liquefactive (brain), fat (pancreas), caseous (lungs).
Neoplasia and Tumor Types
- Neoplasia: new, abnormal cell growth (tumor formation).
- Benign tumors: slow growing, localized, do not invade.
- Malignant tumors: rapid growth, invade tissues, can metastasize (spread).
- Carcinoma: malignant epithelial tumor; sarcoma: malignant connective tissue tumor; adenoma: benign glandular tumor.
Oncogenes, Tumor Suppressors, and Cancer
- Proto-oncogenes: normal genes for cell growth; oncogenes: mutated, cause uncontrolled proliferation.
- Tumor suppressor genes (e.g., p53): halt cell cycle or trigger apoptosis in damaged cells.
- Defective p53 allows abnormal cells to survive and replicate.
Cancer Treatment and Diagnosis
- Chemotherapy targets rapidly dividing cells but can cause immunosuppression.
- Tumor markers indicate disease presence and aid in diagnosis.
- Grading: histological features/anaplasia degree.
- Staging: location and extent of tumor spread.
Key Terms & Definitions
- Pathophysiology — study of body function in disease states
- Etiology — cause or origin of a disease
- Sign — observable disease feature
- Symptom — subjective patient experience
- Homeostasis — stable internal environment maintenance
- Allostasis — adaptive stability to stress
- Apoptosis — programmed cell death
- Necrosis — unregulated cell death due to injury
- Neoplasia — abnormal new cell growth
- Oncogene — mutated gene causing uncontrolled cell growth
- Tumor suppressor gene — gene inhibiting cell proliferation (e.g., p53)
- Grading — degree of tumor cell abnormality
- Staging — extent/location of tumor spread
Action Items / Next Steps
- Review textbook chapters 1, 2, 4, and 7.
- Study definitions and differences between disease types, cell adaptations, and cancer concepts.
- Prepare for quiz by memorizing classifications, stages, and key terminology.