Necrosis & Heat Shock Proteins Flashcards
What is necrosis?
Pathological, unregulated cell death in living tissue causing the release of intracellular contents leading to inflammation
What two processes are involved in necrosis of a cell?
Denaturing of proteins and enzymatic digestion of organelles
What is apoptosis?
Regulated, programmed physiological cell death where the cells own enzymes degrade proteins and the cell is removed by phagocytosis
What are the causes of apoptosis?
Embryogenesis
Hormone-dependent involution in the adult
Cell deletion in populations of cells with normal turnover (eg. Skin, uterine lining)
What is the morphological pattern of death by apoptosis?
Cell shrinkage
Chromatin condensation
Apoptotic bodies (blebbing)
Phagocytosis of apoptotic cells
What form of cell death plays a role in the pathogenesis of neoplasms?
Apoptosis
What are the major differences between necrosis and apoptosis?
Apoptosis = Regulated, normal cell death, Membrane remains intact
Necrosis = Pathological, unregulated cell death
- Membrane bursts leading to release of intracellular contents
- CAUSES INFLAMMATION
What is coagulative necrosis?
Cell death due to ischemia where the outline of the cell remains for days as organelles fade
What is the only form of infarct or ischemia that causes liquefactive necrosis?
Cerebral infarct (stroke)
What is liquefactive necrosis?
- Cell death due to a microbial infection such as a bacterial or fungal infection
- often causes abscesses and high PMNs (Neutrophils) and results in loss of cell architecture
What pathologies does liquefactive necrosis occur in?
Bacterial pneumonia, cerebral infarct (Stroke), acute bacterial meningitis
Liquefactive necrosis is often associated with what morphological pattern of inflammation?
Suppurative
What is an abscess?
A walled off area of liquefactive necrosis by fibrous connective tissue
What type of white blood cell is commonly present in liquefactive necrosis?
Neutrophil (PMNs)
What is gangrenous necrosis?
- Death of body tissue due to loss of blood flow commonly followed by a bacterial infection (wet gangrene) usually in the extremities (feet, hands, legs, arms)
- characterized by conspicuous colour change
What patient population may be at a higher risk for gangrenous necrosis in their legs and feet?
Diabetics
What is caseous necrosis?
Granulomatous inflammation which on the gross appearance gives a cheese-like, yellowish crumbly appearance
What is enzymatic fat necrosis?
- Digestive, enzymatic destruction of adipose cells
- necrosis characterized by fat
What pathology is enzymatic fat necrosis most commonly occurring in?
Pancreatitis
What morphological description can be used to describe enzymatic fat necrosis?
Suponification
Where can enzymatic fat necrosis occur besides the pancreas?
Breast and adipose tissue directly
What is leukopenia?
Low white blood cell count under 5000
What is leukocytosis?
High white blood cell count above 10000
What can leukocytosis indicate?
Infection, cancer
What are heat shock proteins?
Proteins involved in adaptation to stressful/injurious stimuli that play an important role in normal cell metabolism and are essential for survival
When are heat shock proteins induced?
During myocardial infarction and cerebral ischemia
Increased release of heat shock proteins would (Increase/Decrease) cell death and injury?
Decrease
What are examples of heat shock proteins?
HSP 60, HSP 70, and ubiquitin
What are HSP 60 and HSP 70 known as?
Chaperonins
What is the function of HSP 60 and HSP 70?
Protein folding and targeting to final destination
What is the function of ubiquitin?
Facilitates degradation of proteins
