Phagocytes/Leukocytes

Question 1

Leukocytes

Answer 1

Aka (WBCs) are produced in the bone marrow. Normal WBC count 5,000 - 10,000/mm3.

Question 2

Neutrophils

Answer 2

• AKA Polymorphonuclear neutrophils (PMNs). Most abundant - about 60% of our WBCs.
• Predominate in early inflammatory responses around 6-12hrs after initial injury.
• Their job is to ingest bacteria, dead cells, and cellular debris.
• Cells are short lived and become a component of the purulent exudate.

Question 3

Eosinophils

Answer 3

• Mildly phagocytic. Account for about 3% of WBCs.
• Defense against parasites and regulation of vascular mediators.
• Seen in individuals that may have a GI parasitic infection or someone that has/had an allergic reaction.

Question 4

Basophils

Answer 4

• Least prevalent granulocytes. Account for 1% of WBCs.
• Primary role is unknown.
• Act like mast cells.

Question 5

Monocytes

Answer 5

• Account for 6% of WBCs.
• Monocytes are produced in bone marrow, enter the circulation, and migrate to the inflammatory site where they develop into macrophages.

Question 6

Macrophages

Answer 6

• Account for 6% of WBCs.
• Macrophages typically arrive at the inflammatory site 24hrs or later after neutrophils. Very efficient - can live for months to years, are capable of cellular division, and they can proliferate at the site of infection.

Question 7

Dendritic cells

Answer 7

• In peripheral organs and skin. Major link between innate and acquired immune responses.
• Migrate through lymph vessels to lymph tissue and interact with T-lymphocytes to generate an acquired immune response.

Question 8

Natural killer cells (NKC)

Answer 8

• About 30% of WBCs.
• Recognize and eliminate cells infected with viruses.
• Inhibitory and activating receptors to allow differentiation between normal and abnormal cells.
• Produce cytokines and toxic molecules.

Question 9

Phagocytosis

Answer 9

• Process by which a cell ingests and then disposes of foreign material. (Think of them like pac-man).
• Production of adhesion molecules.

Question 10

Margination (pavementing):

Answer 10

Adherence of leukocytes to endothelial cells.

Question 11

Diapedesis

Answer 11

Emigration of cells through the endothelial junctions.

Question 12

Chemotaxis

Answer 12

Migrate towards the area of inflammation.