Lesson 2

• Pathophysiology


  The study of functional or physiologic changes in the body that result from disease processes
• Aspects of pathophysiology


  • Etiology
  • Pathogenesis
  • Changes
  • Manifestations
  • Normal body function (physiology)
  • Homeostasis
• Health


  The state of complete physical, mental, and social well-being and not merely the absence of disease or infirmity
• Adaptation


  The reversible functional and structural responses to changes in physiologic states and some pathologic stimuli, during which new but altered steady states are achieved, allowing the cell to survive and continue to function
• Injury


  The sequence of events that follows once the limits of adaptive responses have exceeded or if cells are exposed to injurious agents or stress, deprived of essential nutrients, or become compromised by mutations that affect essential cellular constituents
• Pathogenesis


  The development of the disease or the sequence of events involved in the tissue changes related to the specific disease process
• Diagnosis


  Identification of a specific disease through evaluation of signs and symptoms, laboratory tests, and other tools
• Etiology


  The causative factor(s) in a particular disease - genetic, congenital defects, microorganisms, immunologic dysfunction, metabolic derangements, degenerative diseases, malignancy, environmental, and nutritional deficiency
• Idiopathic


  Unknown cause
• Iatrogenic


  Diseases caused by error in the treatment, procedure etc.
• Predisposing (risk) factor


  Tendencies that promote development of disease
• Prophylaxis


  Preventive measures to preserve health and spread of disease - intake of certain medications, and undergoing medical procedures
• Prevention


  Strategies and measures that lowers the risk for development or exposure from the disease, thereby preserving health - vaccination, dietary and lifestyle modifications, removal of harmful objects in the environment, cessation of harmful activities (i.e., smoking, alcohol drinking, use of drugs)
• Pathogenesis


  The sequence of cellular, biochemical, and molecular events that follow the exposure of cells or tissues to an injurious agent
• Morphologic changes


  Structural alterations in cells or tissues that are either characteristic of a disease or diagnostic of an etiologic process
• Clinical manifestations


  External features seen among patients as end results of genetic, biochemical, and structural changes in cells and tissues (functional abnormalities)
• Diagnostic test


  Laboratory tests that assist in the diagnosis and monitoring of a specific disease using samples taken from the patient - blood, body fluids, tissue specimen, and secretions
• Precipitating factor


  Condition that triggers an acute episode
• Therapy


  Treatment measures used to promote recovery or slow the progress of a disease - surgery, drugs, physiotherapy, alternatives, behavioral change
• Prognosis


  The probability or likelihood for recovery or other outcomes
• Sequelae


  Potential unwanted outcomes of the primary condition
• Complications


  New secondary or additional problems that arise after the original disease begins
• Characteristics of disease


  • Onset
  • Duration (chronicity)
  • Stage
  • Course
  • Clinical picture
  • Outcome
• Hypertrophy


  An increase in the size of cells, that results in an increase in the size of the affected organ
• Physiologic hypertrophy


  Caused by increased functional demand or by stimulation by hormones and growth factors (i.e., increased workload, pregnancy)
• Pathologic hypertrophy


  Caused by increased functional demand or by stimulation but reaches beyond the reversible point and the organ becomes dysfunctional
• Hyperplasia


  An increase in the number of cells in an organ or tissue in response to a stimulus
• Physiologic hyperplasia


  Due to the action of hormones or growth factors, occurs in several circumstances: when there is a need to increase functional capacity of hormone sensitive organs; when there is need for compensatory increase after damage or resection
• Pathologic hyperplasia


  Mostly caused by excessive or inappropriate actions of hormones or growth factors acting on target cells - endometrial hyperplasia, BPH
• Atrophy


  Reduction in size of organ or tissue due to a decrease in cell size and number
• Physiologic atrophy


  • Notochord and thyroglossal duct undergo atrophy during fetal development
• Pathologic atrophy


  • Decreased workload (atrophy of disuse)
  • Loss of innervation (denervation atrophy)
• Causes of atrophy


  1. Decreased protein synthesis

  2. Increased protein degradation

  3. Fewer mitochondria, myofilaments, RER

  4. Reduced blood supply

  5. Lesser metabolic demand
• Early atrophic cells and tissues have diminished function, but cell death is minimal
• Nutrient deficiency and disuse may activate ubiquitin ligases, which attach the small peptide ubiquitin to cellular proteins and target these proteins for degradation in proteasomes and even autophagy
• Physiologic atrophy


  • Common during normal development
  • Notochord and thyroglossal duct undergo atrophy during fetal development
• Causes of pathologic atrophy

  • Decreased workload (atrophy of disuse)
  • Loss of innervation (denervation atrophy)
  • Diminished blood supply
  • Inadequate nutrition
  • Loss of endocrine stimulation
  • Pressure
• Metaplasia


  Reversible change in which one differentiated cell type (epithelial or mesenchymal) is replaced by another cell type
• Metaplasia


  Represents an adaptive response in which one cell type that is sensitive to a particular stress is replaced by another cell type that is better able to withstand the adverse environment
• Metaplasia does not result from a change in the phenotype of an already differentiated cell type; instead it is the result of a reprogramming of stem cells that are known to exist in normal tissues, or of undifferentiated mesenchymal cells present in connective tissue