$$\text{Serum} = \text{Plasma} - \text{Fibrinogen}$$

Question 1

Which of the following best describes the function of lysozyme found in human tears?

Accepted Answer

Lysozyme destroys the peptidoglycan layer of Gram-positive bacterial cell walls.

Question 2

A patient presents with a fever and increased eosinophil count. Which of the following is the most likely cause?

Accepted Answer

A parasitic worm infestation

Question 3

Which chemical secreted by sebaceous glands helps keep skin pliable and lowers skin pH, thus inhibiting bacterial growth?

Accepted Answer

Sebum

Question 4

What is the primary function of neutrophil extracellular traps (NETs)?

Accepted Answer

To bind and kill bacteria by trapping them in a mesh of DNA and proteins

Question 5

Which of the following is NOT a component of plasma?

Accepted Answer

Platelets

Question 6

During phagocytosis, which step involves the fusion of lysosomes with the phagosome to form a phagolysosome?

Accepted Answer

Killing

Question 7

Which of the following statements about normal microbiota is TRUE?

Accepted Answer

Normal microbiota compete with pathogens for nutrients and help stimulate the second line of defense.

Question 8

Which blood cell type is most involved in adaptive immunity?

Accepted Answer

Lymphocytes

Question 9

A laboratory analysis shows an increase in lymphocytes. What is the most likely explanation?

Accepted Answer

The patient has a viral infection.

Question 10

Which of the following is the correct sequence of events in phagocytosis?

Accepted Answer

Chemotaxis → Adherence → Ingestion → Killing → Elimination

Question 11

Which of the following is a function of the membrane attack complex (MAC) formed during complement activation?

Accepted Answer

MAC drills a hole in the pathogen’s cytoplasmic membrane, leading to cell lysis.

Question 12

Which equation best represents the conversion of plasma to serum?

Accepted Answer

$$	ext{Serum} = 	ext{Plasma} - 	ext{Fibrinogen}$$

Question 13

Which of the following is a characteristic of acute inflammation?

Accepted Answer

It is typically beneficial and important to the second line of defense.

Question 14

Which of the following is TRUE regarding fever?

Accepted Answer

Fever results when pyrogens trigger the hypothalamus to increase the body’s core temperature.

Question 15

Which of the following is a mechanism by which eosinophils kill pathogens?

Accepted Answer

Secreting toxins onto the surface of parasitic helminths

Question 16

Which of the following is a function of natural killer (NK) cells?

Accepted Answer

Secreting toxins onto the surface of virally infected cells and tumors

Question 17

Which pathway of complement activation involves antibodies binding to antigens?

Accepted Answer

Classical pathway

Question 18

Which of the following best describes diapedesis?

Accepted Answer

The passage of blood cells through capillary walls into tissues

Question 19

Which of the following is a role of antimicrobial peptides in innate immunity?

Accepted Answer

They act against a variety of microbes by disrupting membranes and inhibiting cell wall synthesis.

Question 20

A patient’s blood sample shows an increase in neutrophils. Which condition is most likely present?

Accepted Answer

Bacterial infection

Innate Immunity: The Body’s First and Second Lines of Defense

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