Question 1

The allergic response is primarily mediated by _____ antibodies.
A)IgG
B)IgM
C)IgA
D)IgE
E)IgD

Accepted Answer

IgE antibodies are responsible for triggering the allergic response by binding to allergens such as pollen, pet dander, or food proteins. This triggers the release of histamine and other chemicals, leading to symptoms like itching, swelling, and redness. IgG and IgM antibodies are involved in the immune response against infections, while IgA antibodies primarily protect mucosal surfaces. IgD antibodies are involved in the development and maturation of B cells in the immune system.

Question 2

Class I MHC (major histocompatibility complex)is NOT important in
A)fighting cancer.
B)recognizing infected cells.
C)identifying bacterial pathogens.
D)identifying abnormal cells.
E)presenting antigenic determinants.

Accepted Answer

Unlike helper T cells,cytotoxic T cells require class I MHC proteins for activation.This distinction helps explain the major function of cytotoxic T cells-destruction of any of the body's own altered cells that have become cancerous or infected with viruses.The crucial point is that the antigens that complex with class I MHC proteins typically arise within body cells and are thus endogenous antigens.

Question 3

Which of the following statements about antibody-mediated immunity is CORRECT?
A)It primarily defends against viruses that have already infected cells.
B)It is responsible for transplant tissue rejection.
C)It protects the body against cells that become cancerous.
D)It defends against parasites,bacteria,and viruses.
E)It primarily defends against bacteria that have already infected cells.

Accepted Answer

Antibody-mediated immunity, also known as humoral immunity, defends against parasites, bacteria, and viruses by producing specific antibodies that bind to and neutralize foreign pathogens. It does not primarily defend against viruses that have already infected cells (A), nor is it responsible for transplant tissue rejection (B). While the immune system does have mechanisms to protect against cancer, this is primarily through cell-mediated immunity rather than antibody-mediated immunity (C).

Question 4

Which of the following is true of both T cells and B cells?
A)They produce effector cells against specific pathogens.
B)They are produced from stem cells of the lymphatic system.
C)They can attack and destroy invading pathogens.
D)They typically have a short life span.
E)All of these statements are truE.

Accepted Answer

Both T cells and B cells produce effector cells against specific pathogens, are produced from stem cells of the lymphatic system, can attack and destroy invading pathogens, and typically have a short life span.

Question 5

Your patient becomes sick due to an infection by the influenza virus and now has the flu.The cells which would most directly attack and lyse virally infected host cells in this case are __________.These cells mature in the __________.
A)T cells;bone marrow
B)B cells;thymus
C)T cells;lymph nodes
D)B cells;spleen
E)T cells;thymus

Accepted Answer

T cells are the primary cells that directly attack and lyse virally infected cells. They mature in the thymus.

Question 6

During the inflammatory response,dilation of blood vessels is caused by
A)nitric oxide.
B)histamine.
C)cytokines.
D)phagocytes.
E)both histamine and nitric oxidE.

Accepted Answer

Both histamine and nitric oxide can cause dilation of blood vessels during the inflammatory response. Histamine is released by mast cells and causes immediate dilation of local blood vessels. Nitric oxide is produced by endothelial cells and causes a more sustained dilation of blood vessels. Both of these actions increase blood flow to the affected area, allowing for more immune cells to reach the site of infection or injury.

Question 7

A doctor discovers that her patient can produce antibodies against some bacterial pathogens,but he is unable to protect himself against viral infections.The doctor suspects a disorder in her patient's
A)B cells.
B)plasma cells.
C)cytotoxic T cells.
D)suppressor T cells.
E)macrophages.

Accepted Answer

Cytotoxic T cells are primarily responsible for the direct killing of virus-infected cells. A deficiency in these cells would impair the body's ability to combat viral infections, while the ability to produce antibodies against bacterial pathogens (a function of B cells and plasma cells) remains unaffected.

Question 8

_________ is a characteristic of the early stages of a local inflammation response.
A)Arteriole constriction
B)Fever
C)Attack by cytotoxic T cells
D)Release of histamines
E)Release of CD4

Accepted Answer

Release of histamines is a characteristic of the early stages of a local inflammation response. Histamines are released by mast cells and basophils in response to injury or infection, causing vasodilation and increased permeability of blood vessels, which allows for increased delivery of white blood cells to the site of inflammation. This leads to redness, heat, swelling, and pain in the affected area.

Question 9

Which of the following is TRUE of both T cells and B cells?
A)They are lymphocytes.
B)They recognize specific antigens on the cell surface.
C)When activated,they proliferate to form both effector cells and memory cells.
D)They are involved in the humoral immune response.
E)All of the responses are correct.

Accepted Answer

All of the statements are true for both T cells and B cells. T cells and B cells are both lymphocytes that recognize specific antigens on the cell surface. When activated, they form both effector cells (such as helper T cells and plasma cells) and memory cells. They are also involved in the humoral immune response, which is the body's defense against pathogens and foreign substances through the production of antibodies.

Question 10

To infect a cell,HIV must
A)bind both CD4 and a cytokine receptor.
B)bind both CD8 and a cytokine receptor.
C)bind both CD8 and a class I MHC protein.
D)kill cytotoxic T cells and bind CD4.

Accepted Answer

HIV must bind both CD4 and a cytokine receptor to infect a cell. CD4 is a protein found on the surface of certain immune cells that helps in the recognition of foreign particles, while the cytokine receptor plays a crucial role in the communication between cells of the immune system. Binding both of these proteins allows HIV to enter the host cell and replicate. Factors such as the type of cytokine receptor can affect the efficiency of HIV infection.

Question 11

HIV infection and the subsequent destruction of which cell type is most devastating to overall immune system function?
A)cytotoxic T cells
B)memory B cells
C)helper T cells
D)monocytes
E)natural killer cells

Accepted Answer

Helper T cells play a critical role in the activation and coordination of both the humoral and cellular immune responses. HIV specifically targets CD4+ helper T cells, leading to their destruction and compromising the overall immune system function. This results in an increased susceptibility to opportunistic infections and other secondary diseases.

Question 12

Generally speaking,vaccinations are effective in combating future infections because they induce the production of
A)helper T cells.
B)neutrophils.
C)prostaglandins.
D)mutations in the host genome.
E)memory cells.

Accepted Answer

Vaccinations stimulate the production of memory cells, which are long-lived cells that can quickly recognize and mount a response against a specific pathogen if it is encountered again in the future. This is the basis for the effectiveness of vaccinations. Helper T cells, neutrophils, and prostaglandins are all involved in the immune response, but they are not the primary mechanism by which vaccinations confer protection against future infections. Mutations in the host genome are not induced by vaccines.

Question 13

In mammalian defenses against invading pathogens,all of these are considered nonspecific defense mechanisms EXCEPT
A)acquired immunity.
B)the skin.
C)mucous membranes.
D)the inflammatory response.
E)antimicrobial proteins (E.g. ,interferon).

Accepted Answer

Acquired immunity is a specific defense mechanism that involves the recognition and response to specific pathogens, whereas the other options mentioned (skin, mucous membranes, inflammatory response, and antimicrobial proteins) are all nonspecific defense mechanisms that provide a general defense against a wide variety of pathogens.

Question 14

The protection provided through transfer of antibodies from mother to fetus is an example of
A)active immunity.
B)passive immunity.
C)cell-mediated immunity.
D)clonal selection.
E)autoimmunity.

Accepted Answer

The transfer of antibodies from mother to fetus is a form of passive immunity, as the fetus is not producing its own antibodies but rather receiving pre-formed antibodies from the mother's immune system. In active immunity, the individual's own immune system produces antibodies in response to an antigen. Cell-mediated immunity involves the activity of T cells, while clonal selection is the process by which B cells are selected and activated to produce antibodies. Autoimmunity refers to the immune system attacking the body's own cells and tissues.

Question 15

Antigens are
A)non-self proteins.
B)proteins on the surface of B-cell membranes.
C)proteins that consist of two light and two heavy chain polypeptide chains.
D)proteins on the surface of macrophage membranes.
E)proteins on the surface of T-cell membranes.

Accepted Answer

Antigens are foreign substances, such as proteins or carbohydrates, that can trigger an immune response in the body. They are typically recognized as non-self by the immune system.

Question 16

All of the following are components of nonspecific immunity EXCEPT
A)skin.
B)phagocytes.
C)complement.
D)lysozyme.
E)B cells.

Accepted Answer

B cells are a component of specific immunity, not nonspecific immunity. Nonspecific immunity includes physical barriers such as the skin, cellular components such as phagocytes, and soluble molecules such as complement and lysozyme.

Question 17

Which of the following is NOT involved in nonspecific defenses?
A)natural killer cells
B)monocytes
C)neutrophils
D)mast cells
E)B cells

Accepted Answer

B cells are involved in specific defenses, not nonspecific defenses. Nonspecific defenses include natural killer cells, monocytes, neutrophils, and mast cells.

Question 18

It is estimated that humans can produce over 1.5 million different types of antibodies.Which of the following statements regarding this extraordinary variation is INCORRECT?
A)We inherit over 1.5 million different and distinct immunoglobulin genes from our parents at fertilization.
B)V and J domains of antibody light chains are randomly joined.
C)Random segments of DNA can be removed from antibody genes.
D)V and J domains of antibody heavy chains are randomly joineD.
E)Cytosines in the variable regions of antibody genes can be converted to uracils via hypermutation.

Accepted Answer

We do not inherit over 1.5 million different and distinct immunoglobulin genes from our parents at fertilization. Instead, we inherit a limited number of gene segments that can be rearranged in different combinations to produce a vast array of antibodies.

Question 19

Most allergy medicines contain antihistamines that block the actions of histamine.These drugs reduce cold symptoms by directly
A)lysing virus-infected cells to prevent further propagation of the pathogen.
B)stimulating components of the immune system through the release of cytokines.
C)reducing the inflammation response.
D)stimulating the production of specific antibodies.
E)recruiting macrophages to the nasal epithelium.

Accepted Answer

Antihistamines reduce cold symptoms by blocking the actions of histamine, which is responsible for triggering inflammation in response to allergens. By reducing inflammation, antihistamines can alleviate nasal congestion, sneezing, and other allergy symptoms.

Question 20

The clonal selection theory implies that
A)related people have similar immune responses.
B)antigens activate specific lymphocytes.
C)only certain cells can produce interferon.
D)memory cells are present at birth.
E)the body selects which antigens it will respond to.

Accepted Answer

The clonal selection theory proposes that antigens selectively activate specific lymphocyte clones in order to elicit an immune response. This is the basis for the specificity of the immune system. A, C, D, and E are all incorrect because they are not direct implications of the clonal selection theory.

Quiz 41: Immune Systems

The allergic response is primarily mediated by _____ antibodies.

Class I MHC (major histocompatibility complex) is NOT important in

Which of the following statements about antibody-mediated immunity is CORRECT?

Which of the following is true of both T cells and B cells?

Your patient becomes sick due to an infection by the influenza virus and now has the flu.The cells which would most directly attack and lyse virally infected host cells in this case are .These cells mature in the .

During the inflammatory response,dilation of blood vessels is caused by

A doctor discovers that her patient can produce antibodies against some bacterial pathogens,but he is unable to protect himself against viral infections.The doctor suspects a disorder in her patient's

_________ is a characteristic of the early stages of a local inflammation response.

Which of the following is TRUE of both T cells and B cells?

To infect a cell,HIV must

HIV infection and the subsequent destruction of which cell type is most devastating to overall immune system function?

Generally speaking,vaccinations are effective in combating future infections because they induce the production of

In mammalian defenses against invading pathogens,all of these are considered nonspecific defense mechanisms EXCEPT

The protection provided through transfer of antibodies from mother to fetus is an example of

Antigens are

All of the following are components of nonspecific immunity EXCEPT

Which of the following is NOT involved in nonspecific defenses?

It is estimated that humans can produce over 1.5 million different types of antibodies.Which of the following statements regarding this extraordinary variation is INCORRECT?

Most allergy medicines contain antihistamines that block the actions of histamine.These drugs reduce cold symptoms by directly

The clonal selection theory implies that