Leukocytes

Leukocytes

white blood cells, larger than erythrocytes w/ more prominent nuclei

What are the two types of leukocytes

Granulocytes and Agranulocytes

Granulocytes

Cytoplasm contains granules that release when cell is activated, can be seen w dyes

Agranulocytes

no granules in cytoplasm

Functional Characteristics of Leukocytes

• Chemotaxis

• Margination

• Diapedesis

Chemotaxis

attraction to chemical stimuli

CAMs stands for

cell adhesion molecule (protein that helps cells stick to each other)

Margination

Sticks to endothelial cells via CAMs

Diapedesis

ability to squeeze between endothelial cells to migrate out of blood (fight infection)

Neutrophils

A PMN cell that is first to show up to fight infection and survives 1-2 days after leaving blood.

PMN stands for

polymorphonuclear cell

What do neutrophils produce to destroy bacteria

Phagocytic cells, lysosomal cell, and respiratory bust (chemicals made to kill bacteria)

Eosinophils

Bi-lobed nucleus cells found in blood/mucosal linings made to attack large parasites and combat some types of asthma

What do eosinophils produce?

Histaminases, enzymes that break down histamine

Basophils

S-shaped nucleus cells that increase granules and enhances the effect of mast cells (increases inflammation)

Histamine released by granules in basophils causes

vasodilation & increase in capillary permeability which causes inflammation and allergy responses

Heparin releases by granules in basophils cause

anticoagulation which decreases blood clotting

Monocytes

C-shaped nucleus cells that leave the blood to become macrophages, largest WBC and stimulate other cells. Found most in chronic infections

Monocytes stimulate:

1. Chemotaxis

2. Phagocytize and present to lymphocyte

3. Attract fibroblasts to create scare tissues

What are the three classes of lymphocytes

• T cells

• B Cells

• Natural Killer Cells

T-Cells

cellular immunity

B-Cells

antibody immunity

Natural Killer Cells

immunological surveillance

Differential count

counts # of each type of WBC in blood sample indicating what type of infection is present

Leukopenia

inadequate # of WBC = impairs immune response

Leukocytosis

Excessive # of WBC, can be normal during infection

Leukopoiesis

process of producing leukocytes

Process of Leukopoiesis

1. Hemocytoblast

2. Two cell lines:

   • Myeloid Line

   • Lymphoid line

3. Produces committed cells

   • Myeloblast & Monoblast

   • Lymphoblast

The myeloid line produces

every other cell types

The lymphoid line produces

lymphocytes