Apoptosis Flashcards
Apoptosis
Apoptosis is coordinated and genetically programmed cell suicide in which unwanted host cells are eliminated in various physiological and pathological tyms
It is caspase dependent programmed cell suicide
Affecting single cell or small grp of cells
No inflammation and no collateral tissue damage
Energy dependent process
What are the physiological conditions in which apoptosis occur
Embryogenesis (hands formations tail regression)
Physiological involution of cells in harmone dependent tissue eg :endometrial lining amd shedding of ovarian follicles ,regression of lactating breast
Normal cell replacement as in interstial epithelium
Loss of immature b and T cells inBM and thymus
Eliminating blood cells after performing theirs work
What are the pathology conditions apoptosis is seen
Collateral damage occurring to the to host cell in cancer therapy irradiation
Endoplasmic stress if more number of misfolded proteins are accumulated they
Lead to apoptosis
Parkinson’s Alzheimer’s diseases
Cell death by cytotoxic cell I transplant rejection
Certain viral infections =council man bodies in viral hepatitis and cd4 depletion in hiv
What are the morphological features of apoptosis
Small number of cells are involved
Cell shrinkage is the earliest feature due to damage to cytoskeleton
Cell organelles are tightly packed thus imparting eosinophilic nature to cytoplasm
What are the nuclear changes occurring in the apoptosis
Pyknosis = chromatin condensation or nuclear compaction
Karyorrhexix= nuclear fragmentation due to activity of endonuclease
Most characteristic feature
What are morphological features of membrane
Cell membrane shows the blebs and projections
Overall morphological features of apoptosis
Single cell involvement Shrunken Eosinophilia of cytoplasm Pyknosis Karyohexxisi Cell memes blebs Apoptostic bodies Phagocytosis
WhAt are apoptosis bodies
These are cell membrane bound spherical structures containing cell organelles but no nucleus
How can we identify or count the apoptosis cells
Haemotoxylin and feulgen stain the condensed chromatin
Immunoflourscence stain with active caspase 3 anitibody
Fluorescent staining with Annexin v to locate phosphatidyl serine on the surface of cell mem
Mechanism of apoptosis
Extrinsic pathway
Intrinsic pathway
What are prop apoptotic genes
BAX BAK BIM BAD P53 Apaf1 Cytochrome c Corticosteroids Bclx5
Apoptosis
Genetically programmed
Cell suicidal
Atp dependent
What is extrinsic mechanism
Signals comes from outside
Bind to death receptors
It has 2 phases Intiation and execution
Explain initiation phase of extrinsic pathway
Normally death receptors are present on the cells
Two types
FAS/ cd95 receptors
TNF receptors
Stimulus com in the form
fas ligand
Now the receptors come together and form cytoplasmic death domain FADD fas associated death domain
Convert pro caspase 8 to nrml caspase
Fas protein
Fas receptors attached
Multiple fas receptors come together
Cytoplasmic death domain FADD
Pro caspase to caspase
Host for is acted
TNF protein
TNF receptors attached
Multiple receptors come together
Tradd formed on cytoplasmic side TNF receptor associated death domain
Pro caspase to caspase
