Causes of cell injury

1. CAUSES OF CELL
INJURY
BY
MARYAM MANZOOR
LECTURER PHARMACOLOGY
RASHID LATIF COLLEGE OF PHARMACY

2. CELL INJURY
A set of biochemical and morphological changes that occur when a state
of homeostasis is disturbed by adverse influences

3. CAUSES OF CELL INJURY
Oxygen deprivation
Chemical agents
Infectious agents
Immunologic agents
Genetic defects
Nutritional imbalances
Physical agents
Aging

4. OXYGEN DEPRIVATION
•Hypoxia
•interferes with aerobic oxidative respiration.
•Different from ischemia
•Ischemia is the most common cause of hypoxia.
•oxygen deficiency can also result from inadequate oxygenation of the
blood, as in pneumonia.
•Or reduction in the oxygen-carrying capacity of the blood, as in blood-
loss, anemia or carbon monoxide (CO) poisoning.

5. CHEMICAL AGENTS
•Chemical agents can injure the cell.
•Osmotic disturbance---- glucose and salt.
•Poisons cause severe damage-------by altering membrane permeability,
osmotic homeostasis, or the integrity of an enzyme or cofactor.
•Air pollutants , CO, asbestos, insecticides etc.

6. INFECTIOUS AGENTS
•Viruses
•Tapeworms
•Bacteria
•Fungi
•protozoans

7. IMMUNOLOGIC REACTIONS
•Immune reactions can also result in cell and tissue injury.
•Examples include autoimmune reactions against one’s own tissues and
allergic reactions against environmental substances in genetically
susceptible individuals

8. GENETIC DEFECTS
• Congenital malformations associated with Down syndrome
• Single amino acid substitution in hemoglobin S giving rise to sickle cell
anemia.
• Deficiency of functional proteins
• Deficiency of enzymes in inborn errors of metabolism
• Or accumulation of damaged DNA or misfolded proteins--- irreparable
damage.

9. NUTRITIONAL IMBALANCES
• Protein–calorie insufficiency
• Specific vitamin deficiencies .
• Excessive dietary intake may result in obesity and also is an important
underlying factor in many diseases, such as type 2 diabetes mellitus and
atherosclerosis

10. PHYSICAL AGENTS
• Trauma
• Extremes of temperature
• Radiation
• Electric shock
• Sudden changes in atmospheric pressure all have wide-ranging effects
on cells.

11. AGING
•Cellular senescence leads to alterations in replicative and repair abilities
of individual cells and tissues.
•All of these changes result in a diminished ability to respond to damage
and, eventually, the death of cells and of the organism.