Describe the effects of cellmembrane damage.

Plasma membrane damage results in loss of osmotic balance and influx of fluids and ions as well as loss of proteins, enzymes, co-enzymes and ribonucleic acids. The cells may also leak metabolites, which are vital for the reconstitution of ATP thus further depleting net intracellular high energy phosphates. Injury to lysosomal membranes results in leakage of their enzymes into the cytoplasm and activation of these enzymes. Activation of these enzyme leads to enzymatic digestion of cell components resulting in loss of ribonucleoprotein, deoxyribonucleoprotein and glycogen and the cells die by necrosis.

Describe The Biochemical Mechanism Leading To Cell Membrane Damage

The following biochemical mechanism contribute to cell membrane damage:
A. Mitochondrial dysfunction- Defective mitochondrial function results in decreased phospholipid synthesis, which affects all cellular membrane. At the same time increase cytosolic Ca++ activate phospholipases and leading to breakdown of phospholipids. The net result is a depletion of phospholipids from the mitochondria and other dellular membranes and accumulation of free fatty acids. In the mitochondria this changes causes permeability defects.

B. Loss of membrane phospholipids: This is because activation of endogenous phospholipases by increased levels of cytosolic calcium, phospholipid loss can also occur secondary to decreased ATP-dependant reacylation or diminished de novo synthesis of phospholipids.

C. Cytoskeletal abnormalities: Activation of proteases by increased cytosolic Calcium may cause damage to elements of the cytoskeleton.

D. Reactive oxygen species: Partially reduced oxygen free radicals cause injury to cell membranes and to other cell constituents.

E. Lipid breakdown products: These includes unestirified free acids, acyl carnitine and lysophospholipids catabolic products that are known to accumulate in injured cells as a result of phospholipid degradation. They have detergent effect on membrane.