Final answer:
The three types of polymorphonuclear granulocytes (PMNs) are neutrophils, eosinophils, and basophils, each having distinctive staining characteristics and functions in the immune system's response to infection and injury.
Step-by-step explanation:
The three types of polymorphonuclear granulocytes (PMNs) in the human immune system are neutrophils, eosinophils, and basophils. These are all types of white blood cells with a lobed nucleus and visible granules in their cytoplasm after histological staining, with each type having its specific staining characteristics and functions.
- Neutrophils are the most common type of granulocytes that stain light lilac. They have a multi-lobed nucleus and play a crucial role as first responders during injury or infection.
- Eosinophils contain larger granules that stain reddish-orange and have a two to three-lobed nucleus. They are particularly involved in fighting parasitic infections and allergic reactions.
- Basophils are the least common type of granulocytes with large granules that stain dark blue to purple and a two-lobed nucleus. They are part of the inflammatory response and are involved in allergic reactions.
All of these granulocytes are produced in the red bone marrow and have a short lifespan. Each type of granulocyte is classified according to the type of stain that best highlights their granules, and they differ from agranulocytes, such as monocytes and lymphocytes, which have fewer and less obvious granules.