KINE 2011 Lecture Notes - Lecture 19: Thymus, Microorganism, White Blood Cell
Document Summary
Leukocytes (white blood cells), theses are round, are bigger than red blood cells. They originate from the haemopoietinic stem cell in bone marrow they have the same undifferentiated multipotent stem cells as erythrocytes. Total number of wbcs and percentage of each type may vary considerably to meet defense needs. Mobile units of body"s immune defense system. They will eventually leave circulation and go on to fight an infection: focusing here on cells in circulation (blood), other wbc types discussed later (chapter 10) In circulations, there are 5 different types: neutrophils: phagocytes, eat things like bacterial cells to get rid of them. 60-70: eosinophils: defense against parasites (intestinal worms); allergies, basophils: release histamines (allergies); can secrete heparin (blood fat clearance). Rarest wbc, so there is a difficulty in studying them: monocytes: in transit, will become macrophages, dendritic cells in tissues, lymphocytes: two types; b and t lymphocytes. T lymphocytes are part of cell mediated immune response.