Histopathology

• What greek words make up the word 'pathology'?


  Pathos & Logos
• What is pathology?

  study of disease
• Pathos


  disease
• logos


  study
• Involves the investigation of the causes of disease & the associated changes at the levels of cells, tissues, and organs

  Pathology
• 2 words common in pathology


  etiology & pathogenesis
• Is the origin of a disease, including the underlying causes and modifying factors

  Etiology
• Refers to the steps in the development of disease. It describes how etiologic factors trigger cellular and molecular changes that give rise to the specific functional and structural abnormalities that characterize the disease.


  Pathogenesis
• Invented the first compound microscope

  Zaharias Janssen
• Used light microscope to look at thin slices of plant tissue (cork)

  Robert Hooke
• He saw small, box-like structures and coined the termed ' cell'

  Robert Hooke
• O First to see living organisms under a microscope


  Anton van Leeuwenhoek
• Termed these organisms 'animalcules'


  Anton van Leeuwenhoek
• Stated that 'AlI living plants are made of cells'

  Matthias Schleiden
• Developed the first

  two tenets of the cell theory (with Schwann)

  Matthias Schleiden
• Stated 'All living animals are made of celis

  Theodore Schwann
• Developed the first two tenets of the cell theory (with Schleiden)

  Theodore Schwann
• Stated that 'Where a cell exists, there must have been a pre existing cell'"


  Rudolf Virchow
• Developed the third tenet of the cell theory


  Rudolf Virchow
• A central premise of Virchow's theory is that disease 


  starts from a cell as a result of its structural impairment.
• Steady state of hormones

  homeostasis
• process to stop/prevent bleeding and keeping blood inside the blood vessel

  hemostasis
• 1st stage in wound healing

  hemostasis
• Cells undergo what that results in a new steady state when under stress

  adaptation
• CAUSES OF CELL STRESS/INJURY

  1. Oxygen deprivation
  2. Chemical agents
  3. Immunologic reactions
  4. Physical agents
  5. Genetic factors
  6. Infectious agents
  7. Nutritional imbalances
  8. Aging
• Lack of o2 availability iņ tissues

  hypoxia
• Relative deficiency of Po2<blood Arterial Po, <8o mmhg

  Hypoxemia
• Lack of o2 utilizationby tissues


  Dysoxia
• Ischemia/Infarction: Blood flow decreased

  Ischemia
• Ischemia/Infarction: Blood flow cut-off

  Infarction
• 2 general mechanisms for chemical/toxic injury

  1. Combine with molecular component
  2. Convert to reactive toxic metabolites
• MECHANISM OF CELL INJURY

  1. ATP deletion
  2. mitochondrial damage
  3. accumulation of damaged DNA & proteins
  4. influx of calcium
  5. accumulation of reactive oxygen species
  6. increase permeability of cellular membranes
• major causes of ATP depletion

  1. reduced supply of oxygen and nutrients
  2. mitochondrial damage
  3. actions of some toxins
• enzymes activated during the influx of cytosolic Ca2+

  1. phospholipases
  2. proteases
  3. endonucleases
  4. adenosine triphosphatases (ATPases)
• Mitochondrial damage may result

  biochemical abnormalities
• biochemical abnormalities due to Mitochondrial damage include

  ● Failure / Abnormal of oxidative phosphorylation

  ● High conductance formation in mitochondrial pore

  ● Mitochondria signalling distress proteins
• chemical species with a single unpaired electron in an outer

  orbital

  Free radicals
• Free radicals include:

  1. Superoxide
  2. Hydrogen peroxide
  3. HYdroxyl radical
• The plasma membrane can be damaged by:

  1. ischemia
  2. various microbial toxins
  3. lytic complement components
  4. variety of physical and chemical agents
• Affected Protein in: Cystic fibrosis


  Cystic fibrosis transmembrane conductance regulator (CFTR)