Causes of Cell Injury Flashcards
oxygen deficiency. most common cause of all injury and death
hypoxia
hypoxia occurs;
- deficient blood supply
- reduced oxygen-carrying capacity of the blood
- interference of respiratory chain or oxidative phosphorylation
deficiency of blood supply from impeded arterial flow or reduced venous drainage
ischemia
localised area of ischemic necrosis
infarction
reduced of the oxygen-carrying capacity of the blood
✓ due to anemia
✓ due to Hb dysfunction
Causes of Cell Injury
- Hypoxia
- Physical Agents
- Chemical drugs and Toxins
- Infectious Agents
- Immunological reactions
- Genetic Abnormalities
- Nutritional Imbalances
- Workload Imbalances
- Cell Aging
severity of a physical injury may be increased by tissue hypoxia due to associated local vascular injury.
physical agents
commonly known as poisons cause severe damage at the cellular level
chemical drugs and toxins
agents range from the submicroscopic viruses to the large tapeworms.
infectious agents
immune reactions may also cause all injury
immunological reactions
defects may cause cell injury. Example; cell damage due to alterations at the level of DNA.
Genetic Abnormalities
such as avitaminosis and others are important causes of cell injury
nutritional imbalances
prolonged stimulus
workload Imbalances
natural aging, premature aging
cell aging
Mnemonic acronym for agents of disease double “MINT”
✓Malformation-Miscellaneous
✓Infectious-Immune
✓Nutritional-Neoplastic
✓Trauma-Toxicity
reduction in numbers or volume of erythrocytes or quantity of hemoglobin
due to anemia
carbon monoxide poisoning
due to Hb dysfunction
lacerations or crush injuries
direct mechanical trauma
heat (thermal burn) cold (frostbite)
temperature extremes
radioactive isotope emissions or electromagnetic radiation (eg. UV light, x-ray)
radiation
pets chewing electric cords, faulty writing in barns, lightning strike, etc
electrocution
marine mammals have mechanisms to mostly avoid the “bends”
sudden changes in atmospheric pressure
physical agents
• direct mechanical trauma
• temperature extremes
• radiation
• electrocution
• sudden changes in atmospheric pressure
chemical, drugs and toxins
• inorganic poisons
• organic poisons
• manufactured chemicals
• physiologic compounds
• plant toxins
• animal toxins
• bacterial toxins/mycotoxins
infectious agents
• viruses
• bacteria
• fungi
• protozoa
• metazoan parasite
immunologic reactions
• immune response
• hypersensitivity reactions
• autoimmune diseases
genetic abnormalities
• cytogenetic disorders
• mendelian disorders
• multifactorial inheritance
nutritional Imbalances
• deficiencies
• overnutrition
workload Imbalances
• overworked cells
• underworked cells
cell injury occurs if stimulus prolonged and/or exceeds ability to adapt
overworked cells
prolonged lack of stimulation can lead to atrophy and eventually the loss of cells
underworked cells
the cumulative effects of a life time of cell damage leads to a diminished capacity of aged cells/tissues to maintain homeostasis and adapt to harmful stimuli
cell aging
reduction in numbers or volume of erythrocytes or quantity of hemoglobin (Hb)
anemia
