Cellular ageing, cell death, stem cells

Ageing theories

by product accumulation

cross-linking

free radicals

calorie restriction

biological clock

repair mechanism

Unprogrammed cell death

Necrosis

Programmed cell death

Programmed necrosis

apoptosis

autopahgy

Apoptosis

Requires ATP

Dying cells are isolated

Autophagy

induced by lack of oxygen and food deprivation

necrosis

passive

induced by physical or chemical injury on the cell

Dying cells not isolated

Role of performing and granzymes

Cytotoxic T lymphocytes and killer cells contain lyric granules that contain performing that form pores on the membrane of the target cell.

The pore formed allows for the passive diffusion of granzymes, leading to apoptosis

role of apoptosis

Erasing tissues

Creating new structures

Maintenance of constant volume and homeostasis of tissues

tissue involution

degradation of damaged cells

Asymmetric cell division

a stem cell divides into one mother cell, which is identical to the original stem cell, and another daughter cell, which is differentiated

Stochastic differentiation

when one stem cell grows and divides into two differentiated daughter cells, another stem cell undergoes mitosis and produces two stem cells identical to the original