cell death Flashcards
what percentage of cell death occurs in the brain
20-80% depending on region
what are the types of cell death
apoptosis, autophagy, necrosis
autophagy description
cells degrade themselves. detected by the presence of autophagosomes prior to DNA damage
necrosis description
mostly found after injury .mitochondria stop functioning and cell bursts
apoptosis description
programmed cell death.
condensation of chromatin,
aggregation of crescent shaped figures at the nuclear membrane (pyknosis), fragmentatoin of DNA rougly 180 bp. ultimately cells are phagocytoses by macrophages
what is TUNEL staining and what used for
terminal transferase UTP Nick end labeling. labels the nicked areas of DNA using a dNTP labeled with biotin and strepavidin
apoptosis vs autophagy
autophagic vesicles form throughout the cell and form uniform cellular structures that are filled with vesicular structures. apoptosis is characterized by nuclear condensation
necrosis vs apoptosis
cells burst open.
which cells undergo programmed cell death
progenitors, differentiated neurons, and glia.
what percent of progenitors PCD
profound 10-50%
what percent of progenitors neurons
20-80 profound
what percent of progenitors glia
profound 50% of all oligodendrocytes.
what regulates neuronal PCD
trophic support
when is the most cell death
during synaptogenesis and progenitors
what else controls survival
tissue targets (adding a limb causes increased numbers of neuronal survival)
examples of neurotropins
NGF, BDNF, NT-3
TrkA cell types
DRG(70), SCG (95%), trigeminal (70), basal forebrain
TrkC cell types
DRG (20), trigeminal (20), cochlear (50%), vestibular(15%)
TrkB cell types
DRG 30, trigeminal 60, cochlear 15 vestibular 60 nodose 90 basal forebrain and cerebellum
what is the receptor for NGF
TrKA
receptor for BDNF
TrkB
how do neurotropins signal to the soma
they bind in the periphery and are internalized, then trafficked to the soma.
what does the P75 receptor do and why is it significant
it initiates cell death when signaled. it is signaled by pro nerve factors
is cell death active or passive
it is active and requires protein synthesis.
what are the intracellular cell survival pathways
pi3k-akt pathways, MAPK, JNK, CDK
how do the caspases mediate cell death?
macromolecular degeneration and DNA degradation.
what else mediates neuronal survival
depolarization and calcium signaling
