Leucocytes Flashcards
What are leukocytes?
Leukocytes are white blood cells that play an important role in defence and immunity
They account for only about 1% of the blood volume.
What is granulopoiesis?
Granulopoiesis is the formation of granulocytes, which follows a common line of development from myeloblast to myelocyte
Granulocytes include neutrophils, eosinophils, and basophils.
What are the three types of granulocytes?
The three types of granulocytes are:
* Neutrophils
* Eosinophils
* Basophils
How do granulocytes differ in staining?
Granulocytes are named based on the dyes they take up:
* Eosinophils take up eosin (red acid dye)
* Basophils take up methylene blue (alkaline)
* Neutrophils are purple because they take up both dyes
What is the primary function of neutrophils?
Neutrophils protect the body against bacterial invasion and remove dead cells and debris from damaged tissues.
What are chemotaxins?
Chemotaxins are chemical substances released by damaged cells that attract neutrophils to an area of infection.
What is diapedesis?
Diapedesis is the process by which neutrophils squeeze through capillary walls to reach affected areas.
What is phagocytosis?
Phagocytosis is the process by which cells, like neutrophils, engulf and kill bacteria.
What is pus composed of?
Pus consists of dead tissue cells, dead and live microbes, and phagocytes killed by microbes.
What is the role of eosinophils?
Eosinophils are involved in the elimination of parasites and are active in allergic inflammation.
What do eosinophils release when binding to an infecting organism?
Eosinophils release toxic chemicals stored in their granules.
What substances do basophils contain?
Basophils contain heparin, histamine, and other substances that promote inflammation.
What triggers basophils to release their granule contents?
Basophils release their granule contents in response to an allergen binding to antibody-type receptors on their membrane.
What are mast cells?
Mast cells are similar to basophils but are found in tissues rather than in circulation.
What percentage of the total leukocyte count do agranulocytes make up?
Agranulocytes (monocytes and lymphocytes) make up 25 to 50% of the total leukocyte count.
