Cells found in connective tissue that contains many basophilic granules rich in
histamine and heparin sulfate.
They release histamine and heparin reacting to injuries and cause the immediate
reddening and weal of the skin. They are very similar to
basophils
and possibly derived from the same stem cells.
There are two types of mast cells: those from connective tissue and
a distinct set of mucosal mast cells which are T cell dependent on their
activities.