The immune system destroys or neutralizes
a. bacteria.
b. viruses.
c. nonmicrobial foreign substances.
d. cancer cells that arise in the body.
e. All of the choices are correct.
e. All of the choices are correct.
The killing of cancerous cells by the immune system is called
a. immune oversight.
b. immune surveillance.
c. tissue immunity.
d. phagocytosis.
e. hemostasis.
b. immune surveillance.
Chemotaxis
a. refers to the chemical attraction of neutrophils to a site of inflammation.
b. is important only for innate immune responses.
c. is important only for adaptive immune responses.
d. refers to the engulfing of microbes and foreign molecules by macrophages.
e. refers to dilation of blood vessels by chemicals released by damaged tissue cells.
a. refers to the chemical attraction of neutrophils to a site of inflammation.
Which of the following statements regarding phagocytes and phagocytosis is TRUE?
a. Macrophages, monocytes, and mast cells are phagocytes.
b. Contact of phagocytes with microbes stimulates the phagocytes to release chemicals that mediate the inflammatory response.
c. Phagocytosis is stimulated by the presence of proteins called rhodopsins.
d. Phagocytosis is the process by which leukocytes exit the bloodstream.
e. Phagocytosis is a process that only occurs within the bloodstream.
b. Contact of phagocytes with microbes stimulates the phagocytes to release chemicals that mediate the inflammatory response.
Which of the following statements regarding complement is FALSE?
a. Certain complement proteins are always circulating in the blood in an inactive state.
b. Activated complement can form a membrane attack complex, which forms pores in microbe membranes.
c. Activated complement can stimulate cells to secrete inflammation-mediating chemicals.
d. The complement pathway is always dependent upon activation of the first complement protein, C1.
e. Some activated complement proteins activate other complement proteins.
d. The complement pathway is always dependent upon activation of the first complement protein, C1.
After activation of C3 of the complement system, which of these is a role of its component part, C3b?
a. It acts as an enzyme to convert nitric oxide into hydrogen peroxide.
b. It causes vasodilation of local blood vessels.
c. It acts as a chemotaxin for macrophages.
d. It stimulates the conversion of monocytes to neutrophils.
e. It acts as an opsonin that is recognized by phagocytes targeting the microbe for destruction.
e. It acts as an opsonin that is recognized by phagocytes targeting the microbe for destruction.
Which applies to the classical complement pathway, but NOT to the alternative complement pathway?
a. Activation of C3 results in the formation of C3b.
b. There is a cascade of proteins activated, which results in the killing of microbes.
c. Complement proteins serve as opsonins that facilitate phagocyte binding to microbes.
d. Antibodies activate the first complement protein (C1).
e. Complement activation leads to the development of a multiunit protein called the membrane attack complex (MAC).
d. Antibodies activate the first complement protein (C1).
Which of the following statements regarding the lymphoid organs is NOT true?
a. The primary lymphoid organs are the bone marrow and thymus.
b. The thymus secretes protein hormones, collectively called thymopoietins.
c. large numbers of macrophages and lymphocytes are found in the lymph nodes and spleen.
d. The tonsils contain lymphocytes, macrophages, and dendritic cells that respond to microbes in food.
e. Once a lymphocyte reaches a secondary lymphoid organ, it remains there for its lifetime.
e. Once a lymphocyte reaches a secondary lymphoid organ, it remains there for its lifetime.
Cytotoxic T cells
a. secrete perforin, which kills bacteria and viruses by perforating the membrane or coat that surrounds them.
b. are activated by interleukin 1.
c. require Class I MHC proteins to recognize foreign antigens.
d. are converted to plasma cells when activated by MHC proteins.
e. secrete proteins that neutralize bacterial toxins.
c. require Class I MHC proteins to recognize foreign antigens.
The bacteria Mycobacterium tuberculosis has the ability to prevent lysosomal fusion in macrophages. After phagocytosis where would this microbe be found in the macrophage?
a. Autosomes
b. Ribosomes
c. Free in the cytoplasm
d. Mitochondria
e. Phagosomes
e. Phagosomes
Which is NOT a function performed by activated macrophages?
a. They perform phagocytosis.
b. They secrete cell-killing chemicals.
c. They present antigens to T-cells.
d. They secrete cytokines involved in inflammation.
e. They produce antibodies that bind to specific antigens.
e. They produce antibodies that bind to specific antigens.
When an antigen is bound to an antibody, it binds to
a. the heavy immunoglobulin chain only.
b. the light immunoglobulin chain only.
c. a specific antigen-binding site formed by heavy and light chains.
d. a hypervariable region of immunoglobulin DNA.
e. gamma immunoglobulin only.
c. a specific antigen-binding site formed by heavy and light chains.
Which of the following is NOT a systemic effect of IL-1 in response to infection or tissue injury?
a. Induce fever
b. Increased IL-2 receptor expression
c. Stimulate inflammation
d. Secretion of acute-phase proteins by the liver
e. Stimulation of natural killer cells
e. Stimulation of natural killer cells
Which is NOT true about AIDS?
a. It is caused by a retrovirus.
b. It is caused by a virus that contains RNA.
c. It is transmitted by intimate contact with infected blood, sexual intercourse with an infected partner, or by an infected mother to her breast-fed infant.
d. Certain unusual cancers such as Kaposi's sarcoma co-occur with relatively high frequency.
e. The HIV virus preferentially enters and disables B cells
e. The HIV virus preferentially enters and disables B cells
Which two cell types are primarily responsible for graft rejection?
a. B cells and helper T cells
b. Natural killer cells and B cells
c. Marcrophages and natural killer cells
d. Cytotoxic T cells and helper T cells
e. B cells and plasma cells
d. Cytotoxic T cells and helper T cells
Which of the following statements regarding phagocytosis is TRUE?
a. Macrophages are the only phagocytes in human tissues.
b. The microbe engulfed by the phagocyte is killed by lysosomal enzymes and hydrogen peroxide.
c. Phagocytosis is controlled by a negative feedback mechanism whereby phagocytes release chemicals that inhibit further phagocytosis.
d. The microbe engulfed by the phagocyte is killed by the membrane attack complex (MAC).
e. Antibodies found inside lysosomes attack and kill microbes that are engulfed by phagocytosis.
b. The microbe engulfed by the phagocyte is killed by lysosomal enzymes and hydrogen peroxide.
In a patient taking a hypothetical immunosuppressive drug, all adaptive responses are inhibited. All innate immune responses are still functional, although some are reduced in strength. While taking this drug, which of the following events will still occur in response to infection?
a. Antigen interaction with lymphocytes
b. Production of antibodies that bind to antigens
c. B-cell differentiation into plasma cells
d. Vasodilation of local blood vessels
e. Activation of lymphocytes
d. Vasodilation of local blood vessels
One therapy option for an individual with hepatitis C virus is a drug that mimics the action of interferons. Which would be NOT true in a patient taking this drug?
a. Many cells of the body will increase their cellular production of antiviral proteins.
b. The patient will have increased immunity to viral infections.
c. The patient may have increased immunity to the progression of cancer tumors.
d. The patient will have increased immunity to bacterial infections.
e. None of these are true.
d. The patient will have increased immunity to bacterial infections.
You’re working in a clinical lab and your boss has asked you to run a test on a patient’s MHC Class I molecules. You need to isolate some cells from her collected tissues that express the Class I proteins. Which of the following cell types would you NOT use?
a. Red blood cells
b. Liver cells
c. Neurons
d. Skeletal muscle cells
e. Intestinal epithelial cells
a. Red blood cells
Autoimmune diseases are usually treated with drugs that suppress the immune system. Which of the following diseases would NOT benefit from these immunosuppressive drugs?
a. AIDS
b. Multiple sclerosis
c. Myasthenia gravis
d. Rheumatoid arthritis
e. Type 1 diabetes mellitus
a. AIDS
Which of the following cell types binds to antigens on plasma membranes of target cells and directly destroys the cells?
a. Neutrophils
b. NK cells
c. Cytotoxic T cells (CD8 cells)
d. Helper T cells (CD4 cells)
e. B cells
c. Cytotoxic T cells (CD8 cells)
Your patient has a normal helper T cell count, but very little helper T cell activity. Which of the following scenarios may explain this observation?
a. She has a mutation in her MHC II proteins making them ineffective.
b. She has low antibody activity.
c. She has a mutation in the gene for perforin and makes an ineffective version of this molecule.
d. She is HIV positive.
e. None of these answers would explain the observations seen in this patient.
a. She has a mutation in her MHC II proteins making them ineffective.
Natural killer cells
a. are activated by IL-2 and interferon-gamma.
b. only attack bacteria.
c. cannot interact with antibodies.
d. secrete interferon-gamma to activate helper T-cells.
e. have primary responsibility for mass-manufacturing antibodies against foreign antigens.
a. are activated by IL-2 and interferon-gamma.
B cells that differentiate during an initial immune response but remain dormant until being activated during a subsequent exposure to an antigen are called
a. T cells.
b. memory cells.
c. macrophages.
d. monocytes.
e. cytokines.
b. memory cells.
Which is typically present in a person with type O blood?
a. Erythrocytes carrying type A antigen
b. Erythrocytes carrying type B antigen
c. Both anti-A and anti-B antibodies in the plasma
d. Erythrocytes with both type A antigen and type B antigen
e. Plasma that has neither anti-A nor anti-B antibodies
c. Both anti-A and anti-B antibodies in the plasma
Which of the following statements regarding blood-type incompatibilities between a mother and her fetus is TRUE?
a. An Rh-negative fetus may be at risk if its mother is Rh-positive.
b. An Rh-positive fetus may be at risk if its mother is Rh-negative.
c. A fetus with type B blood may be at risk if its mother has type O blood.
d. The risk to an Rh-positive fetus of an Rh-negative mother is lessened if she has previously carried an Rh-negative fetus.
e. The greatest risk to a fetus occurs when both mother and fetus are Rh-positive.
b. An Rh-positive fetus may be at risk if its mother is Rh-negative.
Which type of allergy/hypersensitivity occurs independent of antibodies?
a. Immune-complex hypersensitivity
b. Immediate hypersensitivity
c. Cytotoxic hypersensitivity
d. Delayed hypersensitivity
d. Delayed hypersensitivity
Which of the following is NOT normally a route of transmission of HIV/AIDS?
a. Unprotected sexual intercourse with an infected partner
b. Kissing or contact with items contaminated by the saliva of an infected individual
c. Across the placenta from an infected mother to her fetus during pregnancy or delivery
d. Via breast milk during lactation
e. Transfer of contaminated blood or blood products from one person to another
b. Kissing or contact with items contaminated by the saliva of an infected individual
Which of the following cells of the immune system are capable of phagocytosis?
Check All That Apply
a. Macrophages
b. Neutrophils
c. Dendritic cells
d. Basophils
e. T lymphocytes
a. Macrophages
b. Neutrophils
c. Dendritic cells