Final answer:
Basophils are white blood cells related to mast cells that play a significant role in allergic and hypersensitivity reactions by releasing histamines and other inflammatory mediators.
Step-by-step explanation:
Among the white blood cells, basophils are the cell type that is related to connective tissue mast cells and is particularly involved in allergic and hypersensitivity reactions. Basophils, which contain granules and have a bilobed nucleus, play a crucial role in the body's defense mechanisms. They secrete histamines, which are responsible for dilating blood vessels and increasing their permeability as part of the inflammation process. They also produce heparin, which inhibits blood clotting. Both mast cells and basophils are implicated in releasing inflammatory molecules during allergic responses. In type I hypersensitivity reactions, such as allergies to pollen, these cells release histamine and other mediators that can lead to symptoms characteristic of allergic responses.