Cell injury. By Dr. Abdelaty Shawky Dr. Gehan Mohamed. Learning objectives: . Understand the definition of cell injury. Outline Mechanisms of Cell Injury Recognize the variability in Cellular response to injury which include : - Cellular adaptation
Dr. AbdelatyShawky Dr. Gehan Mohamed
Understand the definition of cell injury.
Outline Mechanisms of Cell Injury
Recognize the variability in Cellular response to injury which include :
- Cellular adaptation
- Reversible cell injury ( nonlethal hit)
- Irreversible injury and cell death (apoptosis, necrosis ).
-Identify the differences between apoptosis and necrosis.
- Recognize the different types of necrosis.
1. Type, duration and severity of injurious agent.
2. The type, status, adaptability, and genetic makeup of the injured cell.
injury to irreversible injury is known as the
POINT OF NO RETURN.
Point of no return
normal, adapted, reversibly injured, and dead myocardial cells
a. Hyperplasia: increase in cell number. e.g. benign prostatic hyperplasia.b. Hypertrophy: increase in cell size. Hypertrophied uterine muscle in pregnancy.c. Atrophy: decrease in cell mass e.g. atrophy of the breast after menopause.d. Metaplasia: change of type of cell to another e.g. squamous metaplasia of urinary bladder epithelium in response to bilharziasis.
1- Decrease ATP production: soPlasma membrane energy-dependent sodium pump is reduced, resulting in cell swelling.
2. Cell membrane damage: leading to Loss of structural integrity and Loss of function.
3. Mitochondrial damage: leading to inadequate aerobic respiration.
4. Ribosomal damage: leading to altered protein synthesis.
5. Nuclear change: leading to abnormal proliferation.
7. Production of oxygen derived free radicals.
* Definition:inadequate oxygenation of tissue.
2. Shifting to anaerobic glycolysis: leads to;
- Due to detachment of ribosomes from the rough endoplasmic reticulum.
4. Impaired calcium ATPase pump:
Influx of Na, H2O
Efflux of K
= hydropic change
Hepatocytes showing fatty change