L58. Cell Injury Flashcards
Describe how cell injury can be reversible or irreversible.
Reversible - cells adapt when a stimulus is applied and revert when the stimulus is removed. It depends on type and severity of the injury.
Irreversible - permanent, can cause cell death.
What is aetiology?
Cause of the disease
What can cause hypoxia?
Anaemia. It disrupts respiratory processes.
What causes ischaemia?
Shortage of blood flow to a tissue caused by artery or vein blockages.
Describe agents which can lead to cell injury.
Physical agents - mechanical trauma, temperature
Infectious agents - bacteria, viruses
Chemicals - poisons, alcohol
Immunological - anaphylaxis
Give examples of specialised and generalised inadequate nutrition.
Rickets - specific
Anorexia - generalised
Give examples of specialised and generalised excessive intake.
Hypervitaminosis - specific
Obesity - generalised
Give an example of a genetic defect.
Sickle cell anaemia
What happens to DNA and plasma during reversible injury?
Their integrity is maintained.
Give examples of 2 changes which can be seen in cells during cell injury.
Cloudy swelling - cells cannot maintain fluid homeostasis
Fatty change - accumulation of lipid vacuoles in cytomplasm
Give the 4 point flow chart for irreversible injury.
Normal cell > reversible changes > point of no return > irreversible changes
What is necrosis?
Irreversible cell injury/death due to pathology
What is pyknosis?
Nucleus shrinkage
What is karyorrhexis?
Nucleus fragments
What is karyolysis?
the blue-stained nucleus DNA is digested by endonucleases
Give a sign of cell necrosis.
loss of blue-stained nucleus.
What are the 3 types of necrosis?
- Co-agulative necrosis - no protein breakdown in cells due to enzyme denaturation
- Liquefactive necrosis - digestion of dead tissue (now in a liquid state - pus)
- Caseous necrosis - tissue has a cheese-like appearance (like in TB).
What is fat necrosis?
Areas of fat destruction brought about by pancreatitis.
What is fibrinoid necrosis?
seen in immune reactions in blood vessels.
Name 2 effects of necrosis
- Loss of function
2. Inflammation
What do nuclei tell you?
Whether or not they have died (pyknosis, karyorrhexis, karyolysis)
What does the cytoplasm tell you?
How it died (co-agulation necrosis, liquefaction necrosis, caseous necrosis, fat necrosis)
What is apoptosis?
genetically programmed cell death which requires energy with no inflammation.
Give 2 causes of apoptosis.
DNA damage or cell deletion during embryogenesis.
Give the 4 stages of apoptosis.
- Cell shrinkage
- Packaging up of the nucleus.
- Intact cell membrane with cytoplasmic blebs
- Blebs break off to form apoptotic bodies which are phagocytosed.
What is atherosclerosis?
Cholesterol accumulation
What is an amyloid?
an abnormal protein which can build up due to pathology caused by chronic inflammation.
Give an endogenous pathological pigmentation.
Melanin in the mouth (internal cause - disease)
Give an exogenous pathological pigmentation
Carbon deposition in the lung alveoli from inhaled smoke (external cause)
What is dystrophic calcification?
Deposits of calcium phosphate in necrotic tissue (normal serum calcium)
What is metastatic calcification?
Deposits of calcium salts in vital tissue with raised serum calcium levels (hypercalcaemia)
Give 2 causes of hypercalcaemia.
Excess vitamin D or renal failure
