Cell Death Flashcards
How do cells die? (3)
Necrosis
Apoptosis
Autophagy
When is apoptosis important?
Embryological development
Normal tissue homeostasis
Neoplastic disease
Apoptosis is used to remove
Unwanted cells in developing tissues
Extrinsic cell death pathways
Signals from external environment causes cells to apoptose
Intrinsic cell death pathways
Intracellular responses to cell damage causes cells to apoptose
Extrinsic pathway (3 parts)
external ligands bind to ‘death receptors’
receptors transduce death signal
activation of caspases
Intrinsic pathways (4 parts)
cell injury, radiation, toxins, free radicals
absence of growth factors
cytochrome c released by mitochondria
activation of caspases
key features of apoptosis, 7
activation of caspases cells shrink lose contact with other cells chromatin condensation membrane blebbing DNA fragmentation packaging of organelles
Apoptotic bodies contain:
intact mitochondria
lysozomes
ribosomes
Apoptotic bodies are phagocytosed by
neighbouring cells or macrophages
In apoptosis, cell contents not allowed to leak into extracellular space, therefore there is no
Inflammatory response
In cell viability test, trypan blue and propidium iodide will only enter
Non-viable, therefore permeable cell
Trypian blue stains cell ….. and the PI stains the nucleus ….
Blue
Red
TUNEL assay is method for detecting ….. by …..
DNA fragmentation
Labelling terminal end of nuclei acid
TUNEL assay relies on nicks in DNA which can be identified by an
enzyme
Apoptest uses flourescent marker attached to
annexin V
In apoptest, flourescent marker will attach to a specific … whch flips to outside during…
Phospholipid
Apoptosis
Autophagy is a form of …. and literally means…..
cell death
eating yourself
Autophagy allows …… of cell components and a source of …. in a starving cell
recycling
energy
Autohpagy steps (4)
cellular componenets for autophagosome
lysozome fuses with autophagosome
lysozyme degrades cell components
raw materials released and made available for energy metabolism
phagocyte involved in apoptosis or autophagy?
Apoptosis
DNA laddering involved in apoptosis or autophagy?
Apoptosis
organelles preserved in vacuoles in apoptosis or autophagy?
Apoptosis
cytoskeleton preserved in apoptosis or autphagy?
autophagy
caspase dependant, apoptosis or autophagy?
apoptosis
Necrosis is cell death resulting from
lethal injury
Necrosis, planned or not?
Not
3 main types of necrosis
coagulative
caseous
liquefactive
in necrosis, release of cell contents leads to (2)
denatured proteins
enzyme release
3 mechanical changes in cellular necrosis
karyorrhexis- nucleus fragmentation
karyolysis- compete dissolution of nucleus
pyknosis- cell shrinkage
in coagulative necrosis, tissue appears
firm and pale as if cooked
tissue affected by coagulative necrosis digested and cleared by
polymorphs and phagocytes
In liquefactive necrosis, cells appear…as a result of…
semi liquid
hydrolytic enzymes
caseous necrosis typically caused by (3)
Mycobacteria
funghi
foreign substances
In caseous necrosis, necrotic area appears
not quite liquid, but outline of tissue doesnt remain
caseous necrotic tissue resembles soft crumbly cheese and is
soft and white
haemotoxykin and eosin makes caseous necrotic tissue appear
homogenously pink
haemotoxykin and eosin makes caseous necrotic tissue appear
homogenously pink
Gangrene is used to describe tissue which is
black and dead
Gangrene is seen mostly in lower …. in patients which severe ….
limbs
aterosclerosis
Dry gangrene occurs mostly with which sort of necrosis
coagulative
Wet gangrene occurs when
tissue is infected with gram -ve bacteria, liquefactive necrosis
Fibrinoid necrosis occurs in…..
what is deposited in damaged necrotic cells?
arteries
fibrin
Autolytic change: where is it seen?
hear stops pumping and cells become irreversibly what?
Enzymes leak from cells and…
post mortem tissue
ischaemic
digest adjacent structures
necrotic tissue may become calcified, when cell undergoes necrosis, large amounts of …. enter the cell, and combines with ….. to produce
calcium
phosphates
crystals
what is dystrophic calcification
extracellular calcification, formed in vesicles
angiogenesis is
the formation of new blood vesseld toprovide blood for a structure.
