Cellular Injury & Defects Flashcards
What causes cell hypoxia?
Ischemia or inadequate oxygen carrying capacity of blood
Name 7 causes of cellular injury
- hypoxia
- physical agents
- chemical agents/drugs
- infectious agents
- immunological reactions
- genetic defects
- nutritional imbalances
A patient’s liver cells responds to toxic injury, what cellular adaptation is occurring?
Focal pathological hyperplasia
A patient with a history of cardiac injury has a cellular reaction occurring with his remaining cardiac myocytes, what cellular adaptation is occurring?
Focal pathological hypertrophy
A chronically bedridden patient is most likely experiencing ______________ of his quadriceps muscles
Atrophy
A patient who is exercising regularly would expect what normal cellular response?
Physiological hypertrophy
Response of bronchial epithelium in a patient who chronically smokes would expect what cellular adaptation?
Squamous metaplasia
Name 4 universal biomechanical themes of cellular injury
- Lack of oxygen
- Increased intracellular calcium
- Depletion of ATP
- Defects in membrane permeability
What can lack of oxygen or excess oxygen cause in a cell?
Decreased synthesis of ATP leading to cell death
What does an increase in intracellular calcium or loss of calcium homeostasis cause?
Activation of calcium dependent enzymes
What does depletion of ATP cause?
Loss of membrane function and intracellular processes
What forms of cellular accumulation are reversible?
Cellular swelling and steatosis
What cellular events occur before the point of no return from hypoxic/ischemic injury?
- compromised aerobic respiration
- increased rate of anaerobic glycolysis
- decreased cellular pH
- decreased ATP -> x mito-> x Na/K ATPase pump -> H2O in = acute cellular swelling
- detachment of ribosomes from RER
- mitochondrial swelling
What cellular events occur due to hypoxia/ischemia after the point of no return, meaning they are irreversible?
- Vacuolization of mitochondria
- Rupture of lysosomes/activation of Ca dependent enzymes
- Nuclear changes (pyknosis, karryorrhexis, karyolysis)
What enzymes can be detected in the blood after lysosomes rupture indicating cell death?
Lactate dehydrogenase and creatine kinase
What is mitochondrial vacuolization?
When a lysosome fuses with mitochondria and causes bursting and swelling resulting in cell death
What is pyknosis?
Small, shrunken, dark nucleus indicating irreversible cell injury
What is karryorrhexis?
Fragmented nucleus indicating irreversible cell injury
What is karyolysis?
Faded nucleus indicating irreversible cell injury
What enzymes are you looking for when taking a blood test for a possible heart attack patient?
High levels of troponin I in the blood as well as elevated levels of creatine kinase and lactate dehydrogenase
What is free radical induced injury?
A final common pathway in a variety of cell processes
Name 4 examples of cellular processes which lead to free radical induced injury
- chemical & radiation injury
- cellular aging
- O2 toxicity
- microbial killing by phagocytes
What does free radical induced injury consist of?
chemical species that are highly reactive and unstable (uneven e-)
What does free radical damage result in?
Lipid peroxidation of cell membranes
Oxidative modification of cell proteins
Damage to cell DNA
What are important attributes of hydrogen peroxide (H2O2)?
Forms free radicals via iron catalyzed Fenton reaction
Diffuses widely within a cell