Pathology part 3 Flashcards
Does necrosis require energy?
No
Is necrosis pathological?
Always
What is coagulative necrosis
Preservation of cell outline
What are dead cells consumed by?
Various enzymatic processes and cells
What is liquefactive necrosis?
Liquid viscous mass- no cell structure remains
Pus
What is liquefactive necrosis associated with?
Localised bacterial and fungal infections in the brain
What is caseous necrosis associated with?
Tuberculosis
ask for couture, PCR and look for result of ziegler neelson stain
What is caseous necrosis?
granulomatous inflammation with central necrosis
Define apoptosis
Programmed cell death in response to specific signals
Does apoptosis require energy?
Yes
Give an example of physiological apoptosis?
digit formation
removal of self reactive lymphocytes
hormonal-depandant involution
What can pathological apoptosis occur as a result of?
Injury
- radiation
- chemotherapy
- viral infection- hepatitis
- cancers
- graft versus host disease
What are the two pathways of apoptosis?
Extrinsic
Intrinsic
Describe the extrinsic pathway of apoptosis
Death receptors initiated pathway
Cell membrane receptors with death domain
What are the death receptors?
TNF and Fas
What is the role of Fas?
Recognition of self
Apoptosis in lymphocytes
What is the role of TNF?
Complex, induces apoptosis in association with inflammatory conditions
What do people with Fas mutations often get?
Autoimmune diseases
Describe the intrinsic pathway?
Mitochondrial pathway
Growth signals promote anti-apoptotic molecules in mitochondrial membrane
What are anti-apoptotic molecules in membrane replaced by?
Bax, Bak
What do Bax, Bak do?
Increase permeability of mitochondria
Release proteins that stimulate caspases
Cytochrome C
What is p53 responsible for?
Sensing cell damage and halting cell cycle
If DNA can’t be repaired then p53 stimulates caspases and induces apoptosis
What does too little apoptosis cause?
Cancer
Autoimmune disorders
What does too much apoptosis cause?
Neurodegenerative disorders
What causes apoptotic abnormalities?
Ischaemic injury
Viral infections
What is the morphology of apoptosis?
Cells shrink (pyknosis)
Chromatin condensation- nucleus clumps and breaks up
Cytoplasmic blebs- cytoplasm breaks up
Macrophages- come in to hoover
What is the cause of cellular ageing?
Many causes;
-oxidative stress- free radical damage
-accumulation of metabolism by-products;
>lipofuscin
