Pathology 4: Cell injury 2 Flashcards
What are mechanisms of cell injury?
ATP Depletion
Membrane damage
Metabolic disturbance
Genetic damage
What does mitochondrial damage lead to?
- Leakage of proapoptotic proteins (point of no return)
- Decrease of ATP with multiple downstream effects
Effects of Ca2+ entry from damage of ions pumps
- Increase of mitochondrial permeability
- Activation of multiple cellular enzymes
Increased in ROS (Reactive oxygen species)
ROS: Metabolites lead to
Damage to lipids, proteins, DNA
Damage to membrane
Plasma membrane damage:
- Loss of cellular components
Lysosomal membrane damage:
- Enzymatic digestion of cellular components
Effects of protein misfolding and DNA damage
Activation of proapoptotic proteins
9 causes of cell injury
- Oxygen deficiency
- Physical damage
- Infectious agents
- Nutrition imbalance
- Genetic damage
- workload imbalance
- Toxic damage
- Immune dysfunction
- Aging
What is ischemia?
Impairment in blood supply to the tissue.
- Physical or mechanical barrier of bloody supply to tissue.
- No O2 or glucose delivered and no water removed.
Infarction
Death of tissue related to ischemia
Oxygen deficiency leads to
Hypoxia
Ischemia
Types of physical damage
Trauma
temp extremes
radiation/electricity
Workload imbalance can lead to
Hypertrophy
Hyperplasia
Atrophy
What is hypoxia? Example?
Lack of oxygen (anemia)
Causes of toxic damage
Chemicals: drugs, toxins
Name of reversible cellular injury- morphologic features
Hydropic degeneration
Hydropic degeneration
- Increased cell size/volume
-Cytoplasmic vacuolation (swollen mitochondria, ER, and Golgi)
What happens when reversible cell injury is becoming irreversible
Acute cell swelling can lead to death
What is necrosis
Cell death of injury by hypoxia, ischemia, cell membrane damage
Acute swelling effects
Swelling can lead to necrosis and point of no return is unclear.
- Restoring O2 supply can lead to free radical creation.
Cell membrane damage due to
Chemical injury
Free radical injury
Anti-oxidant protective mechanisms to avoid free radical injury
- Superoxide dismutase (SOD)
- Glutathione peroxidase
- Vitamins E,C
What is Ischemia-reperfusion injury
- continued damge to tissue following restoration of blood supply to ischemic tissue
- Generation of ROS
- Ca2+ influx, impaired ion pumps
Histologic changes for necrosis
- Cytoplasmic hypereosinophilia
- Nuclear changes: Pykonsis, Karyorrhexis, karyolysis
What is pyknosis?
Nucleus: shrunken, dark, round
What is karyorrhexis?
Nuclear fragments
What is karyolysis?
Pale nucleus (dissolution of chromatin)
Necrosis: morphologic types- gross appearance
- Coagulation necrosis
- Caseous necrosis
- Liquefactive necrosis
- Gangrenous necrosis
- Fat necrosis
What is Coagulation necrosis?
The tissue is dead but the outline of the architecture remains in place
What is Caseous necrosis?
Cheese-like fibrous decay. A lot of leukocytes/WBC fo inflammation response
What is Liquefactive necrosis?
Often in brain, Softening of brain = Malacia
What is Gangrenous necrosis?
- Occurs in the extremities or skin from loss of blood supply
Wet: heavy, wet, full of blood and edema
Dry: usually distal limbs becoming leather-like
What is Fat necrosis?
Will Saponify- Chalky white development of fat.
