Chapter 1: Introduction to Pathophysiology - Vocabulary Flashcards

Pathophysiology: Background and Overview

• Pathophysiology involves the study of functional or physiologic changes in the body that result from disease processes. It builds on knowledge of normal structure and function of the human body.
• Disease development and associated changes to normal anatomy or physiology may be obvious or hidden with a quiet beginning at the cellular level. Pathophysiology includes aspects of pathology, the laboratory study of cell and tissue changes related to disease.
• Health and disease concepts are foundational for understanding patient care and prevention.

Understanding Health and Disease

• Disease may be defined as a deviation from the normal structure or function of any part, organ, or system (or a combination) or from a state of wellness.
• Disease is a definite pathological process with characteristic signs and symptoms.
• The World Health Organization (WHO) definition of health includes physical, mental, and social well-being, not merely absence of disease.
• Health is variable due to genetic differences, life experiences, and environmental influences; context matters when assessing health.
• Homeostasis is the maintenance of a relatively stable internal environment despite external changes.
• Disease develops when significant changes occur that prevent maintenance of homeostasis without intervention.
• Normal indicators (blood pressure, pulse, lab data) are averages or ranges; individual values vary by age, gender, genetics, environment, activity level, etc. Well-trained athletes may have lower resting pulse; blood pressure tends to rise with age in healthy individuals.
• Avoid relying on a single value; consider the whole clinical picture.
• Diseases described in texts are general descriptions; individual variation is expected.

Concept and Scope of Pathophysiology

• Pathophysiology requires knowledge of basic anatomy and physiology and is based on loss or alteration of normal structure and function.
• Diseases often affect one organ/system but impact others due to interconnections (e.g., liver damage impairs clotting factor production, leading to bleeding; jaundice from bilirubin excretion issues).
• Inflammation and infection are common causative processes across multiple diseases.
• The text focuses on major diseases with some coverage of other conditions to show broad application of principles.
• Prevention has become a primary health focus; knowledge of pathophysiology underpins preventive teaching and community health efforts.
• Differences in access to diagnostic tests and resources affect clinical practice; ethical, legal, and social issues accompany new scientific advances (e.g., genetics, AI).
• Three-stage health research process (basic science, safety in humans, large clinical trials) aims to demonstrate safety and effectiveness before regulatory approval. Evidence-based findings drive practice, but ethics, cost, access, and social factors also shape adoption.
• Off-label use: approved therapies may be used for other diseases after third-stage trials; marketing for new uses requires further testing.
• Example: azidothymidine (AZT) showed dramatic survival benefits in trials; trials halted early, then all patients offered access.

Beginning the Process: A Medical History

• A thorough medical history is essential to identify how health interventions may affect, or be affected by, a patient’s condition.
• History includes current and prior illnesses, allergies, hospitalizations, treatments, and current therapies (prescription, nonprescription, herbal, and food supplements).
• A basic form is filled by the patient and then clarified by the clinician via follow-up questions.
• Pathophysiology knowledge helps formulate useful questions, interpret implications, and plan precautions or modifications to prevent complications.
• Examples:
  • Severe respiratory problems or congestive heart failure: difficulty in a supine position; stress reduction may be important for hypertension; prophylactic meds may be needed to prevent infections or bleeding.

New Developments and Trends

• Health care knowledge and technology are rapidly evolving; ongoing updating is required.
• Advances include better understanding of disease causes and pathophysiology, improved diagnostics, and more effective drugs.
• Example: cervical cancer prevention via human papillomavirus (HPV) vaccine reduces future cervical cancer risk, though it does not provide 100% prevention; routine screening remains important.
• Technology expansion includes sensors (e.g., under-skin glucose monitoring and insulin release), artificial intelligence (AI), 3D printing, robotics, and nanotechnology.
• Costs of technology must be weighed against benefits such as reduced hospitalization or chronic care needs.
• Global health agencies (WHO, US Public Health Service, CDC, state/local authorities) collect and publish data to guide research and public health decisions.
• Information sharing and collaboration among agencies and industries are essential for epidemic response and prevention.

Basic Terminology of Pathophysiology

• A strong foundation in anatomy and physiology is essential for understanding pathophysiology.
• Ready References provide selected anatomic terms for review.
• Terminology includes a range of concepts used throughout the discussion of disease processes.

The Disease Process

• Diagnosis: identification of a specific disease using signs, symptoms, tests, or other tools; often requires multiple factors.
• Etiology: causative factors of a disease; can include congenital defects, inherited disorders, microorganisms, immunologic dysfunction, metabolic derangements, degenerative changes, malignancy, trauma, environmental factors, and nutritional deficiencies.
• Idiopathic: disease with unknown cause.
• Iatrogenic: disease caused by a treatment, procedure, or medical error.
• Predisposing factors: tend to promote disease development (high-risk factors like age, gender, genetics, exposure, diet).
• Prophylaxis: measures to preserve health and prevent disease spread (e.g., baby aspirin in high-risk patients).
• Prevention: vaccines, lifestyle changes, removal of hazards, cessation of harmful activities.

Prevention and Public Health

• Primary Prevention: protect healthy people from developing disease or injury; examples include education on nutrition/exercise, seatbelt/helmet use, screening for risk factors, immunization, hazard control at home/work.
• Secondary Prevention: after illness or risk is present; aims to halt progression or limit disability; examples include aspirin for cardiovascular prevention, regular screening for at-risk individuals, modified work for injured workers.
• Tertiary Prevention: manage long-term health problems to prevent further deterioration and maximize quality of life; examples include rehabilitation programs, chronic pain management, patient support groups.

Disease Characteristics

• Pathogenesis: development of disease and sequence of tissue changes.
• Onset: sudden/acute or insidious (gradual) with mild or vague signs; diseases may have several stages.
• Acute vs Chronic: acute is short-term with prominent signs; chronic is long-lasting and may cause permanent tissue damage; often interspersed with acute episodes.
• Subclinical state: pathologic changes exist without obvious manifestations due to reserve capacity.
• Latent/Incubation: incubation period is the time from exposure to signs; disease may be communicable during this period.
• Prodromal period: early development with nonspecific signs (fatigue, anorexia, headache); tests may be negative.
• Manifestations: signs (objective) and symptoms (subjective).
• Local vs Systemic: manifestations can be localized or general.
• Lesion: a local tissue change (microscopic or visible).
• Syndrome: collection of signs and symptoms affecting more than one organ.
• Diagnostic tests: laboratory tests, tissue/cell analysis, microbiology, radiologic imaging; quality assurance is essential; repeat testing with the same lab aids comparison.
• Remissions and exacerbations: remission is a decrease/subsidence of manifestations; exacerbation is a worsening.
• Precipitating factors: trigger an acute episode (distinct from predisposing factors).
• Complications: new secondary problems arising from the primary disease (e.g., CHF after MI).
• Therapy: treatments to promote recovery or slow progression (surgery, drugs, physiotherapy, alternative therapies, lifestyle changes).
• Sequelae: potential unwanted outcomes after the primary condition (e.g., paralysis after stroke).
• Convalescence: recovery period returning to baseline health.

Disease Prognosis

• Prognosis: probability or likelihood of recovery or other outcomes; based on averages; individual variation is common.
• Consideration of the data basis (group size, study duration) is important.
• Morbidity: disease rates or functional impairment within a population.
• Mortality: relative number of deaths from a disease.
• Autopsy (postmortem): examination to determine cause of death and disease course; conducted by a pathologist.
• Epidemiology: science of tracking disease patterns; data presented in graphs, tables, maps; essential for understanding transmission, distribution, and control.
• Notifiable/reportable diseases: must be reported to designated authorities; reporting aims to prevent further spread (examples include measles, SARS, HIV/AIDS in some jurisdictions).
• Incidence vs Prevalence:
  • Incidence: number of new cases in a population over a period; used to analyze changing factors. ext{Incidence} = rac{ ext{Number of new cases during a period}}{ ext{Population at risk during that period}}
  • Prevalence: total number of existing cases (new + old) at a given time; typically larger than incidence. ext{Prevalence} = rac{ ext{Number of existing cases}}{ ext{Total population}}
• Epidemics and pandemics: higher-than-expected cases in a region; pandemics involve multiple regions globally.
• Examples: influenza patterns inform annual vaccine composition; major data centers include WHO (Ottawa) and CDC (Atlanta).

Introduction to Cellular Changes

• Cells adapt their growth and differentiation in response to altered conditions; some adaptations are normal (pregnancy-related tissue changes).
• Reversible adaptations occur when stimulus is removed; irreversible changes may indicate DNA alterations or dysfunction.
• Abnormal cellular changes may not always lead to tissue damage or cancer, but require monitoring to reduce risk.

Terms Used for Common Cellular Adaptations

• Atrophy: decrease in cell size, reducing tissue mass; causes include reduced use, malnutrition, reduced stimulation, aging; example: muscle shrinkage during immobilization.
• Hypertrophy: increase in cell size, enlarging tissue mass; occurs with increased work (e.g., heart hypertrophy from high demand) or hormonal stimulation; examples include exercised skeletal muscle.
• Hyperplasia: increase in cell number, enlarging tissue mass; may accompany hypertrophy; compensatory or pathologic in hormonal imbalance; risk of cancer in some cases.
• Metaplasia: replacement of one mature cell type with another; may be adaptive but can reduce tissue defenses; cigarette smoke example: ciliated columnar epithelium replaced by stratified squamous in the respiratory tract.
• Dysplasia: cells vary in size/shape, enlarged nuclei, increased mitotic rate; may be precancerous; detected via screening tests like Pap smears.
• Anaplasia: undifferentiated cells with variable structure and numerous mitotic figures; common in many but not all malignant tumors; basis for tumor grading.
• Neoplasia: new growth; neoplasms can be benign or malignant (cancer); benign tumors do not necessarily become malignant, but location and context matter (e.g., brain).
• Think About 1.4: differentiate hypertrophy, hyperplasia, anaplasia, and dysplasia.

Cell Damage and Necrosis

• Apoptosis: programmed cell death; normal in development and aging; cells digest themselves into apoptotic bodies, engulfed without inflammation.
• Necrosis: death of cells/tissue due to irreversible damage; many causes include ischemia, physical, chemical, microbial, nutritional deficiencies, and electrolyte imbalances.
• Ischemia: reduced oxygenated blood supply due to obstruction; a major cause of cell injury.
• Hypoxia: reduced tissue oxygen; especially damaging to high-demand tissues like brain, heart, kidney; disrupts ATP production and Na+/K+ pump, leading to cell swelling and rupture; anaerobic metabolism → lactic acidosis and acidification.
• Other injury mechanisms: physical injury, radiation, chemicals (exogenous and endogenous free radicals), microorganisms causing direct injury or pyroptosis (inflammatory-type cell death).
• Pyroptosis vs apoptosis: pyroptosis involves cell lysis and inflammatory response, unlike apoptotic bodies which are cleared silently.
• Altered metabolism and genetic defects can cause toxic intermediates that destroy cells.
• Necrosis progression: initial reversible injury → morphological changes; with continued injury, cell death occurs and nucleus may disintegrate; enzymes released from dead cells can indicate tissue injury (e.g., cardiac enzymes in myocardial infarction).
• Necrosis types:
  • Coagulative necrosis: cell proteins denature; tissue retains structure for a time (common in myocardial infarction).
  • Liquefactive necrosis: tissue becomes liquid due to enzymatic digestion (e.g., brain infarction).
  • Fat necrosis: fatty tissue broken down into fatty acids in infection or enzyme action; increases inflammation.
  • Caseous necrosis: coagulative-like necrosis yielding a thick, yellowish “cheesy” substance (TB example).
• Infarction: area of dead cells due to lack of oxygen; large infarcts cause significant loss of function (e.g., myocardial infarction).
• Gangrene: necrotic tissue with infection, often due to poor blood supply; dry gangrene (coagulative necrosis) vs wet gangrene (liquefactive necrosis) and gas gangrene.
• Brain death vs somatic death: modern criteria focus on brain death via protocols/tests; major organs may be supported artificially after death criteria are met.
• Case context examples and figures referenced in the text (e.g., Fig. 1.3 on necrosis patterns; Fig. 1.4 TB caseous necrosis).

Think About 1.5 and Case Considerations

• Consider how different forms of necrosis influence clinical decisions, including amputation in gangrene to prevent spread.
• Note organ-specific death rates: brain tissue dies quickly (4–5 minutes) without oxygen; heart tissue can survive about 30 minutes.

Case Study A (1.1)

• Ms. A, age 35, Pap test showed marked cervical dysplasia without infection.
• Questions include:
  • Discuss purposes and uses of diagnostic testing in this scenario.
  • Relate prognosis, latent stage, remission, exacerbation, predisposition to the scenario.
  • Compare dysplasia with other cellular adaptations and testing methods.

Chapter Summary

• Disease is a deviation from the individual’s normal state, leading to loss of homeostasis.
• Pathophysiology studies the structural and functional changes related to disease processes; manifestations depend on organ/ tissue and cause (infection, malignancy, etc.).
• Prevention and screening campaigns rely on knowledge of etiology and incidence; ethical and resource considerations are important when adopting new technologies.
• The pathway from disease manifestation to treatment involves signs, symptoms, diagnosis, prognosis, and therapy; cellular adaptations (atrophy, hypertrophy, hyperplasia, metaplasia, dysplasia, anaplasia, neoplasia) explain many disease processes.
• Cell damage can be reversible or irreversible; necrosis types and their consequences influence clinical outcomes and interventions.
• Real-world applications include public health measures, biomedical research, and clinical decision-making, all of which are shaped by evolving technologies and ethical considerations.

Study Questions

• 1. Choose a specific disease and prepare six descriptive terms; define each term.
• 2. Define and give examples for: a) etiology, b) incidence, c) precipitating factor, d) complication, e) prognosis, f) iatrogenic, g) sequelae.
• 3. Differentiate metaplasia from malignant neoplasm.
• 4. Describe cellular changes leading to: a) loss of function, b) necrosis.
• 5. Define: a) apoptosis, b) gangrene.
• 6. List preventive practices to reduce disease risk.
• 7. Case vignette: CJ undergoing breast cancer surgery; relate to diagnosis, medical history, etiology, prognosis, benign neoplasm, iatrogenic, signs, complication, treatment, cancer, and examination of living tissue. Some terms may be used more than once.

THINK ABOUT 1.1

• Describe the stages of the health sciences research process.
• What is the purpose of a double-blind trial?
• What is a placebo, and why is it used in some studies?

APPLY YOUR KNOWLEDGE 1.1

• Using the heart and lungs, apply prior anatomical/physiological knowledge to pathophysiology by predicting the loss of function when part of normal structure is altered.

TECHNOLOGY

• Artificial Intelligence in Health Care (AI):
  • AI analyzes large data sets to assist diagnosis and drug design, and to personalize medical plans.
  • Limitations exist; AI complements but does not replace clinical judgment.

New Challenges: The Zika Virus (Box 1.2)

• Zika virus discovery and international health response history; illustrates rapid data sharing among agencies to manage potential epidemics.

1.1 APPLY YOUR KNOWLEDGE (Box prompts)

• Use the heart and lungs to apply anatomy/physiology to pathophysiology studies; predict functional loss when normal structure is altered.

Notes on Numbers, Data, and Formulas

• Incidence and prevalence definitions and their relationship:
  • Incidence: ext{Incidence} = rac{ ext{Number of new cases during a period}}{ ext{Population at risk during that period}}
  • Prevalence: ext{Prevalence} = rac{ ext{Number of existing cases (new + old)}}{ ext{Total population}}
• Epidemic = higher-than-expected cases in a region; pandemic = higher cases across large geographic areas.
• Notifiable diseases are those that must be reported to authorities to prevent spread and protect public health.

Illustrative Figures and Concepts (as described in text)

• Fig. 1.1 illustrates incidence vs prevalence and epidemic/pandemic concepts.
• Fig. 1.2 depicts abnormal cellular growth patterns (atrophy, hypertrophy, hyperplasia, metaplasia, dysplasia, neoplasia).
• Fig. 1.3 displays patterns of necrosis (coagulative, liquefactive, fat) and examples (kidney infarct, brain infarct, necrotic fat, dry gangrene).
• Fig. 1.4 shows TB with caseation necrosis and Ghon focus/complex.

Key Takeaways for Exam Preparation

• Understand how pathophysiology links normal structure/function to disease processes and to patient management.
• Be able to define etiology, idiopathic/iatrogenic, predisposing factors, prophylaxis, and prevention, and explain how they influence patient care.
• Differentiate among the major cellular adaptations and necrosis types; recognize when necrosis might lead to specific clinical interventions (e.g., amputation in gangrene).
• Recognize the differences between signs and symptoms, and between local and systemic manifestations.
• Recall the three levels of prevention and examples of each.
• Appreciate how epidemiology informs public health decisions, including incidence, prevalence, and reporting requirements.
• Be prepared to discuss how advances in technology (AI, vaccines, diagnostics) raise ethical, legal, and social considerations in health care.