51) Which of the following are the MOST active type of leukocytes, phagocytically, and are usually the first to arrive at an injury site?

A) neutrophils

B) eosinophils

C) basophils

D) lymphocytes

E) erythrocytes

52) ________ are large phagocytic WBCs that remain in circulation for only about 24 hours before entering peripheral tissues to become tissue macrophages.

A) Neutrophils

B) Eosinophils

C) Basophils

D) Lymphocytes

E) Monocytes

53) The white blood cells that are important in leaving the blood vessels and phagocytizing large materials, releasing chemicals that draw fibroblasts to the injured areas, are

A) neutrophils.

B) eosinophils.

C) basophils.

D) lymphocytes.

E) monocytes.

54) Which cell population of WBCs migrate to sites of injury and cross the capillary wall to accumulate within damaged tissues, where they discharge their granules into the interstitial fluids?

A) monocytes

B) eosinophils

C) basophils

D) lymphocytes

E) neutrophils

55) Thrombocytopenia is defined as a deficiency of

A) antibodies.

B) erythrocytes.

C) platelets.

D) eosinophils.

E) neutrophils.

56) Platelets are

A) giant, multinucleated cells.

B) cytoplasmic fragments.

C) immature leukocytes.

D) fixed macrophages.

E) surface antigens.

57) Platelets

A) are phagocytic.

B) are a major component of the vascular clotting system.

C) are a component of the unformed elements of blood.

D) are lymphocytes.

E) have multi-lobed nuclei.

58) How long do platelets circulate before being removed by phagocytes?

A) 9-12 days

B) 6-18 hours

C) 2-3 days

D) 4-8 weeks

E) 1-2 months

59) A blood clot attached to the wall of a vessel is called a(n)

A) embolus.

B) thrombus.

C) plaque.

D) coagulant.

E) platelet plug.

60) Drifting blood clots, air bubbles, or fat globules are called ________.

A) thrombi

B) plaques

C) clotting factors

D) emboli

E) hemostatic elements