Slides in this set
Is a programmed cell death involved in development that occurs in
· The Tail of a tadpole falls off as it changes into a frog.
· Also in humans, apoptosis kills off tissue that link fingers to
prevent webbed hands…read more
Cells should normally die in an orderly fashion, undergo 50 mitotic
divisions (hayflick constant) and a series of other stages leading to
a tidy cell death.
Whereas cell necrosis is an untidy and damaging cell death which
generally occurs after a trauma involving the release of hydrolytic
1. The cytoskeleton is broken down by enzymes.
2. The cell shrinks as cytoplasm condenses and organelles become
tightly packed, the membrane blebs and the nucleus starts to
disintegrate. Chromatins condense and nuclear envelope breaks.
3. Cell breaks up into vesicles
4. Phagocytosis occurs whereby the cell fragments are ingested
and digested by phagocytic cells e.g. WBCs. (components are
reused, no harmful enzymes released)…read more
The process is controlled by a range of signals e.g. cytokines,
hormones, growth factors and nitric oxide.
Different tissues use different signals.
(nitric oxide induces apoptosis it acts as a vasodilator making the
mitochondrial membrane more permeable to H+ destroying the
proton gradient)…read more