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A response that is uniquely directed against pathogenic Bordetella pertussis would involve what component?


First line defenses have what aspect in common with each other?

They are physical barriers against invading pathogens.

Both the innate and adaptive defenses of the immune system work to prevent

the penetration and colonization by pathogens, and the diseases they cause.

If a new bacterial pathogen entered a human body through an accidental needle stick, the first cell that would try to kill the pathogen would likely be

a phagocyte.

What direct effect do histamines and leukotrienes have on capillaries?

They allow capillary walls to open and become leaky.

Diapedesis is

the migration of phagocytes through blood vessels to the site of tissue damage.

Why is vasodilation important to tissue repair?

It allows for an increased delivery of oxygen, nutrients, and phagocytes to the site of damage.

Pus is comprised of

dead phagocytes.

Which of the following can release histamines?

Cells from damaged tissues and the complement pathway

Which type of cell directly attacks infected cells?

Cytotoxic T-cells

Cytokines are produced by which of the following cells?

Helper T-cells

HIV directly infects T-cells. Why is this problematic for cell-mediated immunity?

Cytotoxic T-cells begin to attack the virally infected T-cells, reducing the number of T-cells in the body.

How do helper T-cells and cytotoxic T-cells work together?

Helper T-cells produce cytokines to activate other cells of the immune system.

Which receptor on the helper T-cell recognizes the specific antigen from an antigen-presenting cell?


TH2 cells produce cytokines that activate

B cells.

Which proteins on the antigen-presenting cell are recognized by the helper T-cell?

MHC proteins

When do helper T-cells develop into TH1 or TH2 cells?

After proliferation into a clonal population

Natural killer cells are activated by

TH1 cells.

You step on something in the yard and get a puncture wound that does not bleed freely. Antigens from any microbes that entered the wound will most likely end up in the

lymph nodes of the groin.

The humoral immune response is attributed to the action of

B lymphocytes.

Which of the following cytokines act as a signal between leukocytes?


A single B lymphocyte can recognize multiple antigenic determinants.


Cytokines are soluble regulatory proteins that act as intercellular signals and include substances such as interleukins, interferon, and growth factors.
Cytokines are soluble regulatory proteins that act as intercellular signals and include substances such as interleukins, interferon, and growth factors.


Where are MHC molecules located on a cell?

On the surface of the cell

What is a feature of the small fragments presented by MHC-I proteins?

They are small peptides, roughly 8-10 amino acids long.

Which organelle assists directly with the presentation of MHC-I antigens?

The endoplasmic reticulum

When does MHC-II loading occur?

During the fusion of vesicles containing MHC-II proteins with vesicles containing digested pathogens

Which of the cells listed below can present antigens on Class II MHC proteins?


Which of the following are phagocytic cells found in the epidermis?

dendritic cells

Which of the following contributes to protecting the eyes from microbial invasion?

tears contain lysozyme and salt and mechanically flush particles from the eyes.

The resident microbiota have no role in defense against pathogen invasion.


What does the plasma membrane of a phagocyte attach to on a microorganism?


The process by which a phagocyte moves toward a chemical signal at the site of an infection is called


Which of the following phagocytic processes occurs last in the sequence?


What is the role of opsonins?

They create "handles" that make it easier for the pseudopods of phagocytes to attach to the microbe invader.

What is a phagolysosome?

The structure that results from the fusion of a phagosome and a lysosome.

Chemotaxis is

the movement of cells toward or away from a chemical stimulus.

Which of the following is NOT one of the signs of inflammation?


Some Toll-like receptors (TLRs) are found on the surface of host cells and recognize specific microbial molecules.


Interferons work against viruses.


The complement cascade results in

damage resulting in cell lysis.

Diapedesis is the process of

the squeezing of cells through the lining of capillaries to attack invading microbes.

Opsonization is

the coating of a pathogen by complement.

Stage 1 in phagocytosis

Chemotaxis of phagocyte to microbes

Stage 2 in phagocytosis

Adherence. Phagocytes attach to microorganisms

Stage 3 in phagocytosis

Ingestion of microbes by phagocytes

Stage 4 in phagocytosis

Fusion of a series of vesicles, including lysosomes

Stage 5 in phagocytosis

Killing of microbes by enzymes and other chemicals

Stage 6 in phagocytosis

Elimination (exocytosis)

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