Cell Injury: Intracellular accumulations Flashcards
What is the most common cause of acute cell injury underlying human disease?
Hypoxia and Ischemia
What are the causes of hypoxia?
Reduced blood flow
Inadequate oxygenation of blood
Decreased oxygen-carrying capacity of the blood
Hypovolemia
What is the mitochondrial permeability transition?
Results from damage causing a high-conducting channel in the inner mitochondrial membrane
Leakage of cytochrome c triggers apoptotic death
What are the major causes and result of ATP deletion?
Reduced supply of oxygen and nutrients, mitochondrial damage, and some toxins
Causes reduced activity of Na-K pump, and consequently, cellular swelling and blebbing
What are four things that can cause defects in membrane permeability?
ROS
Decreases Phospholipid synthesis
Increased phospholipid breakdown
Cytoskeletal abnormalities
What is released as a result of myocardial necrosis?
Troponin
Creatine kinase
Describe reperfusion injury.
The restoration of blood flow to ischemic, but viable tissues results in the death of cells that are not otherwise irreversibly injured.
Typically associated with neutrophilic infiltrates with free radicals
What are the mechanisms of reperfusion injury?
Increase in the production of ROS from the increased supply of O2
Calcium overload that began during acute ischemia is aggravated due to cell membrane damage and ROS mediated injury
Inflammation response to dead tissue recruits neutrophils to the ischemic site
How do free radicals cause cell injury?
Lipid peroxication
Oxidative modifcation of proteins
Lesions in DNA
Compromised cellular antioxidant defense mechanisms by ischemia
What is carbon tetrachloride?
Compound that is converted into a toxic free radical in the liver by P450
What is Steatosis?
Fatty Liver
Caused by alcohol, diabetes and obesity, CCl4 and protein malnutiriton, hypoxia, starvation
What is the most common cause of fatty change in developed nations? Developing nations?
Developed - Alcoholism
Developing - Kwashiorkor
What are four types of intracellular accumulation mechanisms?
Abnormal metabolism (Fatty change)
Abnormal protein folding (a1 antitrypsin deficiency)
Lack of enzyme (lysosomal storage diseases)
Indigestible material (pathologic calcification)
What is anthracosis?
Carbon in the lung - common in miners and people in an urban envrionment
What is brown atrophy?
Accumulation of lipofuscin, a granular intracellular material that acucmulates in a variety of tissues as a function of age or atrophy
