Blood - Neutrophils, Eosinophils, Basophils, Monocytes, and lymphocytes

What are neutrophils?

Granular WBCs that are highly mobile and phagocytic.

What percentage of circulating WBCs are neutrophils?

50–70%.

What is another name for neutrophils?

Polymorphonuclear leukocytes.

What does the nucleus of a neutrophil look like?

Multilobed.

How long do neutrophils live in the bloodstream?

10 hours or less.

What is the main function of neutrophils?

Phagocytize and destroy bacteria.

Which WBCs usually arrive first at an injury?

Neutrophils.

What is pus?

A mixture of dead neutrophils and cellular debris.

What is degranulation?

Reduction in the number of cytoplasmic granules as their contents are released.

What chemicals do neutrophils release that help inflammation?

Prostaglandins and leukotrienes.

What are eosinophils?

Granular WBCs that attack parasites and help regulate inflammation.

What percentage of circulating WBCs are eosinophils?

2–4%.

What do eosinophils engulf?

Bacteria, protozoa, and cellular debris.

What do eosinophils attack by releasing toxic compounds?

Large parasites.

What are eosinophils sensitive to?

Allergens.

How do eosinophils help control inflammation?

They release enzymes that reduce inflammation caused by mast cells and neutrophils.

What are basophils?

Granular WBCs that enhance local inflammation.

What percentage of circulating WBCs are basophils?

Less than 1%.

What does histamine do?

Dilates blood vessels.

What does heparin do?

Prevents blood clotting.

How do basophils affect inflammation?

They enhance local inflammation by releasing histamine and other chemicals.

What are monocytes?

Large agranular WBCs that become macrophages in tissues.

What percentage of circulating WBCs are monocytes?

2–8%.

How long do monocytes remain in the bloodstream?

About 24 hours.

What do monocytes become after entering tissues?

Macrophages.

What is the main function of macrophages?

Aggressively engulf large pathogens and debris.

What chemicals do monocytes/macrophages release?

Chemicals that attract other phagocytes and fibroblasts to injured areas.

What are lymphocytes?

Agranular WBCs involved in specific immune defenses.

What percentage of circulating WBCs are lymphocytes?

20–40%.

What is the main function of lymphocytes?

Specific defense against foreign substances and abnormal cells.

Where are most lymphocytes found?

Lymphatic organs and connective tissues.

What are the 3 classes of lymphocytes?

T cells, B cells, and natural killer cells.

What do T cells do?

Carry out cell-mediated immunity and coordinate immune responses.

What do B cells do?

Carry out humoral immunity involving antibodies.

What do B cells differentiate into?

Plasma cells that produce antibodies.

What do natural killer (NK) cells do?

Detect and destroy abnormal cells.