New histopathology

• What is the definition of Histopathology?

  Histopathology is the study of tissue changes caused by disease.
• What are the purposes of histopathological examinations?


  To identify disease, understand tissue changes, and guide treatment.
• What is required for laboratory safety in the Histology laboratory?


  Awareness of safety protocols and proper handling of specimens.
• What is the correct procedure for processing surgical and autopsy tissue specimens?


  To process, prospect, and embed the specimens properly.
• How should a manual microtome be operated?


  It should be operated safely to section paraffin processed blocks of tissue.
• What is the standard for preparing blood smears?

  Blood smears should be prepared to clinical laboratory standards.
• What are routine and special staining procedures used for?


  To enhance the visibility of cells and tissues under a microscope.
• What is pathology?


  Pathology is the study of disease by scientific methods.
• How is disease defined in pathology?


  A disease is an abnormal variation in structure or function of any part of the body.
• What are the four aspects of disease studied in pathology?

  • Etiology
  • Pathogenesis
  • Morphologic changes
  • Functional derangements and clinical significance
• What does etiology refer to in the context of disease?


  Etiology refers to the cause of the disease.
• What are the two major classes of etiologic factors?


  • Genetic factors
  • Environmental factors
• What are the four categories of genetic diseases?


  Chromosomal disorders, Mendelian disorders, single gene diseases, and multifactorial disorders.
• What are the classifications of environmental factors causing disease?

  • Physical agents
  • Chemicals
  • Nutritional deficiencies and excesses
  • Infections and infestations
  • Immunological factors
• What are examples of physical agents that can cause disease?

  Trauma, radiation, extremes of temperature, and electric power.
• How do chemicals cause injury?


  They can act generally or locally, affecting specific organs or all cells.
• What is the difference between infection and infestation?


  Infection is the invasion by pathogenic organisms, while infestation is the establishment of arthropods on a host.
• What role do immunological factors play in disease?


  They protect against microorganisms but can also lead to disease if abnormal.
• What are morphologic changes in pathology?


  Morphologic changes are structural alterations in cells or tissues due to disease.
• What are gross and microscopic morphologic changes?


  Gross changes are visible to the naked eye, while microscopic changes require a microscope.
• How do cells respond to physiologic stresses or pathologic stimuli?


  Cells can undergo adaptation to achieve a new steady state and preserve viability.
• What are the principal adaptive responses of cells?


  • Atrophy
  • Hypertrophy
  • Hyperplasia
  • Metaplasia
• What is atrophy?


  Atrophy is the shrinkage in the size of the cell.
• What are some causes of atrophy?


  Decreased workload, loss of innervation, diminished blood supply, inadequate nutrition, loss of endocrine stimulation, and aging.
• What is hypertrophy?

  Hypertrophy is an increase in the size of cells and consequently the size of the organ.
• What can cause hypertrophy?


  Increased functional demand or specific hormonal stimulation.
• What is hyperplasia?


  Hyperplasia is an increase in the number of cells in an organ or tissue.
• How do hypertrophy and hyperplasia often develop?


  They often develop concurrently in tissues or organs.
• What are the types of physiologic hyperplasia?


  Hormonal hyperplasia and compensatory hyperplasia.
• What is metaplasia?


  Metaplasia is a reversible change where one adult cell type is replaced by another adult cell type.
• How does metaplasia occur?


  It arises by genetic "reprogramming" of stem cells or undifferentiated cells.
• What are the two patterns of morphologic change correlating to reversible injury?


  Cellular swelling and fatty change.
• What is cellular swelling?


  Cellular swelling is the first manifestation of almost all forms of injury to cells.
• What is fatty change?


  Fatty change is the appearance of lipid vacuoles in the cytoplasm due to injury.
• What are the two principal patterns of cell death?

  • Necrosis
  • Apoptosis
• What characterizes necrosis?


  Necrosis is characterized by cellular swelling, protein denaturation, and organelles breakdown.
• What is the most common manifestation of necrosis?


  Coagulative necrosis is the most common manifestation of necrosis.
• What happens to dead cells in terms of morphology?

  Dead cells show increased eosinophilia and may appear glassy and homogeneous.
• What are the three patterns of nuclear changes in dead cells?

  Karyolysis, pyknosis, and karyorrhexis.
• What is coagulative necrosis?


  Coagulative necrosis implies preservation of the basic structural outline of the coagulated cell or tissue.