Types of Leukocytes and its functions

Lab 4: Cardiology - Blood Histology, Blood Vessels & Heart Dissection

neutrophils (granulocyte)

• release hormones called cytokines that attract other phagocytes to a site of injury

  • phagocytize microbes such as bacteria at local wound sites

• cells are short lived (about 10 hours in blood) and may only live 30 minutes until they succumb to the toxins released by the pathogens they have ingested

• make potent oxidizing agents and peptides capable of destroying bacteria

  • has 2 to 5 lobed nucleus (MULTI-LOBED)

eosinophils (granulocyte)

• fight multicellular PARASITIC infections and PARASITIC eukaryotes (ex. worms) in the gut

  • releases destructive enzymes that digest their targets

  • bi-lobed nucleus & cytoplasm filled with orangish granules

basophils (granulocyte)

• migrate to injured tissue and release histamine (vasodilator) and heparin (anticoagulant)

  • histamine initiate a localized inflammatory response

• mast cells in the tissues are very similar to basophils and induce a similar inflammatory response

• bi-lobed nucleus & cytoplasm filled with violet-blue granules

lymphocytes (agranulocyte)

• main cells that populate lymph nodes, glands and other lymphatic tissue

• responsible for the specific immune response to infection

• 2nd most abundant leukocytes and mature into T cells and B cells that orchestrate cellular and humoral (antibody) immunity

  • some T cells attach to and destroy foreign cells by releasing cytotoxic chemicals

  • B cells become sensitive to a specific antigen, then synthesize and release antibodies into the blood

• has large, round, dark0staining nucleus that takes up NEARLY the entire cell

  • size of lymphocyte is variable

monocytes (agranulcoyte)

• when monocytes migrate out of the bloodstream, they become large, phagocytic cells called macrophages

• have little function in circulating blood

  • highly phagocytic toward bacteria and viruses

    • present antigens (from previously phagocytized material) that help activate the immune system

• kidney shaped/round nucleus and large amount of cytoplasm