Granule (cell biology)

In cell biology, a granule can be any structure barely visible by light microscopy. The term is most often used to describe a secretory vesicle.

Leukocytes

A group of leukocytes called granulocytes contain granules and play an important role in the immune system. The granules of certain cells, such as Natural killer cells, contain components which can lead to the lysis of neighboring cells.

Platelets

The granules of platelets are classified as dense granules and alpha granules.