2. INDEX
• CELL INJURY
• OXYGEN DEPRIVATION
• PHYSICAL AGENT
• CHEMICAL AND DRUG AGENTS
• INFECTIOUS AGENTS
• IMMUNOLOGICAL AGENTS
• GENETIC ABNORMALITIES
• NUTRITIONAL IMBALANCES
3. CELL INJURY
SEQUENCE OF EVENTS THAT OCCURS WHEN STRESSES EXCEED
ABILITY OF CELLS TO ADAPT IS KNOWN AS CELL INJURY.
TYPES OF CELL INJURY
• REVERSIBLE CELL INJURY
• IRREVERSIBLE CELL INJURY
4. OXYGEN DEPRIVATION
• HYPOXIA CAUSES CELL INJURY BY REDUCING AEROBIC OXIDATIVE
RESPIRATION.
• VERY IMPORTENT AND COMMON CAUSE OF CELL INJURY AND CELL
DEATH.
CAUSES
• ISCHEMIA : DUE TO CARDIO-RESPIRATORY FALIURE.
• ANEMIA : DECREASE OXYGEN CARRYING CAPACITY OF BLOOD.
• CARBON MONOXIDE POISONING AND SEVERE BLOOD LOSS.
6. PHYSICAL AGENTS
AGENTS WHICH ARE CAPABLE OF CELL INJURY ARE
• MECHANICAL TRAUMA
• EXTREMES OF TEMPERATURE (BURNS AND DEEP COLD)
• SUDDEN CHANGES IN ATMOSPHERIC PRESSURE
• RADIATION
• ELECTRIC SHOCK
8. CHEMICAL AGENTS AND DRUGS
• GLUCOSE OR SALT IN HYPERTONIC CONCENTRATIONS MAY
CAUSE CELL INJURY BY DERANGING ELECTROLYTE.
• EVEN OXYGEN AT HIGH CONCENTRATIONS IS TOXIC.
• TRACE AMOUNT OF POISONS LIKE ARSENIC, CYANIDE, OR
MERCURY.
• OTHER POTENTIAL CAUSES ARE ENVIRONMENTAL POLLUTANTS,
INSECTICIDES, HERBICIDES;
• INDUSTRIAL AND OCCUPATIONAL HAZARDS LIKE CARBON
MONOXIDE AND ASBESTOS.
10. INFECTIOUS AGENTS
• THESE AGENTS RANGE FROM SUBMICROSCOPIC VIRUSES TO
TAPEWORM SEVERAL FEET IN LENGTH.
OTHER AGENTS ARE
• RICKETTSIAE
• BACTERIA
• FUNGI
• PARASITES
12. IMMUNOLOGIC REACTIONS
• AUTOIMMUNE DISEASES ARE THE MAIN CAUSE OF
IMMUNOLOGICAL REACTIONS.
• INJURIOUS REACTIONS TO ENDOGENOUS SELF ANTIGENS
ARE RESPONSIBLE FOR CELL INJURY.
13.
14. GENETIC ABNORMALITIES
• GENETIC ABNORMALITIES AS EXTREME AS AN EXTRA
CHROMOSOME, AS IN DAWN SYNDROME.
• SUBTLE GENETIC ABNORMALITIES AS SINGLE BASE PAIR
SUBSTITUTION LEADING TO AN AMINO ACID SUBSTITUTION, AS IN
SICKLE CELL ANEMIA.
GENETIC DEFECTS MAY CAUSE
• CELL INJURY IN INBORN ERROR OF METABOLISM
• ACCUMULATION OF DAMAGED DNA
• MISFOLDED PROTEINS
16. NUTRITIONAL IMBALANCES
• MAJOR CAUSE OF CELL INJURY
• PROTEIN CALORIE DEFICIENCIES CAUSE AN APPALLING NUMBERS OF
DEATHS.
• DEFICIENCIES OF SPECIFIC VITAMINS ARE FOUND THROUGHOUT THE
WORLD.
• NUTRITIONAL SHORTAGE CAN BE SELF-IMPOSED, AS IN ANOREXIA
NERVOSA.
• NUTRITIONAL EXCESS IS ALSO A CAUSE OF CELL INJURY, OBESITY IS
ASSOCITED WITH AN INCREASED INCIDENT OF SEVERAL IMPORTANT
DISEASES I.E. DIABETES AND CANCER.
