Apoptosis

Intended/controlled cell death

Intrinsic pathway

triggered by stress or DNA damage (regulated by the mitochondria)

Extrinsic pathway (mitochondrial)

Activated by external signals like death molecules binding to death receptors on the cell membrane.

Essential for

Removing cells that are diseased or damages

Removal of malfunctioning cells

Example of developement

Formation of fingers or wearing away the inner lining of the uterus

What does it destroy?

Infected cells

Cells with DNA damage

Cancer cells

Mitochondrial Pathway

Death receptor

Stage 1

Capsases are activated in the cell

Stage 2

Cell contents are digested by caspases

Stage 3

Cell shrinks and the Nucleaus condenses

Stage 4

Cell membrane blebs and fragments.

Stage 5

Partition of cytoplasm and nucleaus into apoptotic bodies that are cleared by phagocytes.

Phagocytosis

After apoptosis, the cellular wate must be removed. Specialised white blood cells called phagocytes eat the apoptotic bodies in a process called phagocytosis

Necrosis

Cell death that is triggered by external factors (disease, trauma infection

Death receptor

when activated by its ligand, it triggers a signaling cascade that leads to the activation of caspase