2. Causes and Mechanisms of Cell Injury and Cell Death Flashcards
(42 cards)
What are three different types of disease?
Genetic
Acquired
Multifactorial
What is the aetiology of genetic disease?
Chromosomal disorders- abnormal numbers and abnormal structures
Prenatally acquired gene disorders - single gene disorders
What are the features associated with downs syndrome?
Increased incidence with increasing maternal age Congenital Heart Disease Predesposition to Leukaemia Early Alzheimer's Disease Learning Disability
What is CF?
Single gene mutation on chromosone 7
A disorder of ion transport in epithelial cells
What are features of CF?
Alteration in the mucus produced at epithelial surfaces
Thick mucus plugs ducts and tubules of glands
High sweat sodium and chloride concentration
Chronic Lung Disease
Pancreatic insufficiency
Malnutrition
Male Infertility
What is significant about autosomal dominant inherited single gene disorder?
the defective product of the gene is usually a structural protein, not an enzyme. Structural proteins are usually defective when one of the allelic products is nonfunctional;
What is significant about enzymes of autosomal recessive inherited single gene disorders?
enzymes usually require both allelic products to be nonfunctional to produce a mutant phenotype:
What is the aetiology of acquired disease?
Infections
Enviromental- chemical + physical
Nutritional
What is a deficiency of vitamin C?
Scurvy
What is a deficiency of vitamin D?
Rickets
What is the aetiology of multifactorial disease?
A combination of genetic factors and environmental factors
When does cell injury occur?
Occurs when cells are stressed so severely they are no longer able to adapt
What are the two types of cell injury?
Reversible (non-lethal) and irreversible (death)
What is the cellular response to stress?
Stress leads to an cell adaptation and if there is an inability to adapt this will lead to a cell injury
What is the cellular response to severe cell injury?
Causes an irreversible injury which will lead to either necrosis or apoptosis
What is the cellular response to mild cell injury?
Reversible injury where the normal cell will resume through homeostasis
Stress will lead to an adaption
An injury stimulus will cause another cell injury
What happens in the cell during injury?
Mechanical Disruption of cells Insufficient energy Blockage of metabolic pathways Failure of membrane pumps Generation of free radicals Damage to DNA Release of lysosomal contents
What does damage to ATP lead to?
Loss of energy dependent cellular fucntions
What does cell membrane damage lead to?
Mitochondrial failure -ATP
Lysosomes -required for enzymatic digestion of cellular components
Plasma membrane- loss of cellular contents
Why is ATP depletion important?
tissues with low glycolytic activity eg neurons, cardiac muscle where ATP depletion is dependent on oxidative phosphorylation
What causes early release of calcium into the cytosol?
Ischaemia and some toxins
Cytosolic free calcium levels are 10 fold lower than extracellular fluid and maintained by ATP dependent pumps
What can lead to oxidative stress?
Reactive oxygen species (free radicals) accumulate when production exceeds the cells antioxidant defences
What is the significance of the loss of the plasma membrane?
Maintain ionic balance between compartments occurs as a primary or secondary consequence of virtually all types of cell injury and particularly affects the mitochondria
What are examples of reversible cell injury?
Reduced oxidative phosphorylation resulting in depletion of ATP energy stores
Cellular swelling caused by changes in ion concentrations and water influx.
