Lysosomes perform several functions including intracellular digestion, extracellular digestion, autophagy, autolysis, and heterophagy. Intracellular digestion occurs entirely within cells and breaks down food, while extracellular digestion happens outside cells such as when sperm fuse with eggs. Autophagy is when lysosomes digest cellular organelles or food reserves, and autolysis is self-destruction of cells by their own lysosomal enzymes, such as during aging. Heterophagy is digestion of exterior material phagocytosed by cells.

1. Functions of lysosomes
Intracellular digestion
Extra cellular digestion
Autophagy
Autolysis
Heterophagy

2. Intracellular digestion
The digestion which entirely takes place inside the cell.
Intracellular digestion is a form of digestion which
takes place within the cytoplasm of the organism.
Intracellular digestion takes place in animals without a
digestive tract, in which food items are brought into
the cell for digestion.

3. Extracellular digestion
The digestion which takes place outside the cell.
A sperms role is to deliver a male’s nucleus to egg.
The sperm head contains a single and highly specialized
lysosome called the acrosome.
Acrosome release the enzymes (Hyaluronidases) that
allows the sperms to fuse with egg. (Extracellular digestion)
1.Zona paluceda
2.Corona rediata

5. Autophagy
Auto=self phagy=eating
When lysosomes eat reserve food(stored ;protein or
lipid)or faulty cellular organelle (mitochondria) it is
called autophagy.
Examples:
Mitophagy: The removal of damaged
mitochondria.

7. Autolysis
The destruction of whole cell by its own
enzyme,released by lysosomes.
Examples:
Autolysis occurs in ageing,or diseased
cells.
The disappearance of larval organs
during metamorphosis ( e.g. tail in frog) is due to
autolysis.
actually cells of tail destroyed.

8. Heterophagy
 digestion of exterior material taken into a cell
by phagocytosis.