Leukocytes and the Immune System Quiz

Which of the following is the most abundant type of white blood cell (WBC) in healthy adult human blood, accounting for approximately 62.0% of the total WBCs?

• Eosinophils

• Basophils

• Monocytes

• Neutrophils

• Lymphocytes

What is the approximate average number of white blood cells (WBCs) per microliter of blood in a healthy adult human?

• 500,000

• 1,000

• 7,000

• 150,000

• 5,200,000

Monocytes, while still in the blood, are described as immature cells with little ability to fight infectious agents. What do they become once they enter the tissues, often increasing their diameter as much as fivefold?

• Neutrophils

• Lymphoblasts

• Macrophages

• Erythrocytes

• Platelets

Which process describes the movement of neutrophils and monocytes squeezing through the intercellular gaps between endothelial cells of blood capillaries and postcapillary venules into tissue spaces?

• Ameboid motion

• Chemotaxis

• Opsonization

• Diapedesis

• Exocytosis

Which characteristic of a particle or substance is least likely to promote its phagocytosis by neutrophils and macrophages, according to the selective procedures for phagocytosis?

• A rough surface on the particle.

• Adherence of antibodies to the particle's membrane.

• The presence of C3 molecules (from the complement cascade) attached to the particle.

• A natural substance of the body with a protective protein coat.

• Being a dead tissue or foreign particle without a protective coat.

The monocyte-macrophage cell system, also known as the reticuloendothelial system, is a widespread defense system throughout the body. Which of the following cell types is not considered a core component of this system?

• Mobile macrophages

• Fixed tissue macrophages

• Kupffer cells in the liver sinusoids

• Alveolar macrophages in the lungs

• Neutrophils

What is the primary role of Kupffer cells in the liver sinusoids, particularly regarding bacteria from the gastrointestinal tract?

• To synthesize hemoglobin.

• To produce bile pigment bilirubin.

• To phagocytize bacteria, preventing their entry from the portal blood into general systemic circulation.

• To store iron in the form of ferritin.

• To regulate red blood cell production based on oxygen levels.

During an inflammatory response, which cells provide the first line of defense within minutes by rapidly enlarging and, for previously sessile cells, becoming mobile?

• Neutrophils from the blood.

• Newly produced granulocytes and monocytes from bone marrow.

• Macrophages already present in the tissues (e.g., histiocytes, alveolar macrophages, microglia).

• Lymphocytes.

• Basophils.

Eosinophils are weak phagocytes but are often produced in large numbers in response to which type of infection, and they kill these invaders by attaching to them and releasing substances such as hydrolytic enzymes, reactive forms of oxygen, and major basic protein?

• Bacterial infections

• Viral infections

• Parasitic infections

• Fungal infections

• Autoimmune conditions

Acute total leukopenia, a severe decrease in the number of white blood cells, can lead to which of the following life-threatening conditions if untreated?

• Increased resistance to infection.

• Rapid invasion of adjacent tissues by bacteria, leading to ulcers and severe infections, often resulting in death without treatment.

• A significant increase in red blood cell production.

• Enhanced blood clotting.

• Muscle hypertrophy.