Chapter 22 Review

List the specific functions of each of the body's lymphoid tissues and organs.

1.Lymph nodes: filtration of lymph, detection of pathogens, initiation of immune response 2.Lymphoid nodules, and MALT: defense of entrance and passageways of digestive tract and protection of epithelia lining the respiratory, urinary, and reproductive tracts against pathogens and foreign proteins or toxins 3.Spleen: filtration of blood, recycling of red blood cells, detection of blood-borne pathogens or toxins 4.Thymus: production of mature T cells and hormones that promote immune function 5.Lymphatics: movement of lymph from interstitial spaces to the venous system

Give a function for each of the following:

1.cytotoxic T cells-lymphocytes responsible for cell-mediated immunity 2.helper T cells-stimulate the activation and function of T cells and B cells 3.suppressor T cells-inhibit the activation and function of both T cells and B cells 4.plasma cells-produce and secrete antibodies 5.NK cells-recognize and destroy abnormal cells 6.stromal cells-produce interleukin-7, which promotes the differentiation of B cells 7.reticular epithelial cells-maintain the blood-thymus barrier and secrete the thymic hormones that stimulate stem cell division and T cell differentiation 8.interferons-interfere with viral replication inside the cell and stimulate activities of macrophages and NK cells 9.pyrogens-reset the body's thermostat, causing a rise in body temperature(fever) 10.T cells-provide cell-mediated immunity, which defends against abnormal cells and pathogens inside cells 11.B cells-provide humoral immunity, which defends against antigens and pathogens in the body (but not inside cells) 12.interleukins-enhance innate (nonspecific) defenses and increase T cell sensitivity and stimulate B cell activity 13.tumor necrosis factor-slow tumor growth and kill sensitive tumor cells 14.colony-stimulating factors-stimulate the production of blood cells in the bone marrow and lymphocytes in lymphoid tissues and organs

The most beneficial effect of fever is that it

1.inhibits the spread of some bacteria and viruses 2.increases the metabolic rate by to 10 percent

Give one example of each type of immunity: innate immunity, naturally acquired active immunity, artificially induced active immunity, artificially induced passive immunity, and naturally acquired passive immunity.

Innate immunity is genetically programmed; an example is immunity to fish diseases. naturally acquired immunity develops after birth from contact with pathogens; an example is exposure to chickenpox in grade school. artificially induced active immunity develops after intentional exposure to a pathogen; an example is administration of measles vaccine. artificially induced passive immunity is temporary immunity provided by injection with antibodies produced in another organism, such as antibodies against rabies. natural passive immunity is gained by acquiring antibodies via mother's milk or placental exchange.

Perforins are proteins associated with the activity of

NK cells

What are the three classes of lymphocytes, and where does each class originate?

T cells, derived from the thymus B cells, derived from bone marrow NK cells, derived from bone marrow

Paula's grandfather is diagnosed as having lung cancer. His physician takes biopsies of several lymph nodes from neighboring regions of the body, and Paula wonders why, since his cancer is in the lungs. What would you tell her?

a key characteristic of cancer cells is their ability to metastasize to break free from a tumor and form new tumors in other tissues. The primary route of metastasis is the lymphatic system, including the lymph nodes. the primary route of metastasis is the lymphatic system, including the lymph nodes. examination of regional lymph nodes for the presence of cancer cells can help the physician determine if the cancer was caught in an early stage or whether it has started to spread to other tissues.

Willy is allergic to ragweed pollen and tells you that he read about medications that can help his condition by blocking certain antibodies. Do you think that this treatment could help willy? Explain.

allergies occur when allergens bind to specific IgE antibodies that are bound to the surface of mast cells and basophils. a person becomes allergic when they develop IgE antibodies for a specific allergen. theoretically, at least, a molecule that would bind to the specific IgE for ragweed allergen and prevent the allergen from binding should help to relieve the signs and symptoms of the allergy.

Blocking the antigen receptors on the surface of lymphocytes would interfere with

antigen recognition

Compare and contrast the effects of complement with those of interferon.

complement can rupture the target cell's plasma membrane by releasing perforin, kill the target cell by secreting a cytotoxic lymphotoxin, or activate genes within the nucleus of the cell that stimulate programmed cell death (apoptosis). interferon interferes with viral replication and virus-infected cells by triggering the production of antiviral proteins.

How does a cytotoxic T cells destroy another cell displaying antigens bound to Class I MHC proteins?

cytotoxic T cells kill by rupturing the target cells' plasma membrane, by stimulating lymphotoxin secretion, or by activating genes in the nucleus that program cell death.

Phagocytes move through capillary walls by squeezing between adjacent endothelial cells, a process known as

diapedesis

How does the formation of an antigen-antibody complex cause the elimination of an antigen?

formation of an antigen-antibody complex eliminates antigens by neutralization; by agglutination and precipitation; by activating complement; by attracting phagocytes; by opsonization; by stimulating inflammation; or by preventing bacterial and viral adhesion.

Skin tests are used to determine if a person

has been exposed to a particular antigen

A decrease in which population of lymphocytes would impair all aspects of an immune response?

helper T cells

CD4 markers are associated with

helper T cells

While walking along the street, you and your friend see an elderly woman whose left arm appears to be swollen to several times its normal size. Your friend remarks that the woman must have been in the tropics and contracted a form of filariasis the produces elephantiasis. You disagree, saying that it is more likely that the women had a radical mastectomy (the removal of a breast of cancer). Explain the rationale behind your answer.

in a radical mastectomy, lymph nodes in the nearby axilla and surrounding region are removed along with the cancerous breast to try to prevent the spread of cancer cells via the lymphoid system. lymphatic vessels from the limb on the affected side are tied off, and because there is no place for the lymph to drain, over time lymphedema causes swelling of the limb.

The major histocompatibility complex (MHC)

is a group of genes that codes for human leukocyte antigens

Anatomically, lymph vessels resemble

medium veins

What seven defenses, present at birth, provide the body with the defensive capability known as innate (nonspecific) resistance?

physical barriers phagocytic cells immunological surveillance interferons complement system inflammation fever

Compared with innate defenses, adaptive defenses

protect against threats on an individuals basis

Lymph from the right arm, the right half of the head, and the right chest is received by the

right lymphatic duct

Red blood cells that are damaged or defective are removed from the bloodstream by the

spleen

Complement activation

stimulates inflammation attracts phagocytes enhances phagocytosis

Ted finds out that he has been exposed to measles. He is concerned that he might have been contracted the disease, so he goes to see his physician. The physician takes a blood sample and sends it to a lab for antibody levels and titers. The results show an elevated level and activity of IgM antibodies to rubella (measles) virus but few IgG antibodies to the virus. Has Ted contracted the disease?

ted cannot yet know whether he'll come down with the measles. ted's elevated blood IgM level and titer indicates that he is in the early stages of a primary response to the measles virus. if his immune response proves unable to control and then eliminated the virus, ted will develop the measles.

An anesthesia technician is advised that she should be vaccinated against hepatitis B, which is caused by a virus. She is given one injection and is told to come back for a second injection in a month and a third injection after six months. Why is this series of injections necessary?

the injections are timed to trigger the primary and secondary responses of the immune system. upon first exposure to hepatitis antigens, B cells produce daughter cells that differentiate into plasma cells and memory B cells. the plasma cells begin producing antibodies, which represent the primary response to exposure. however, the primary response does not maintain elevated antibody levels for long periods, so the second and third injections are necessary to trigger secondary responses, when memory B cells differentiate into plasma cells and produce antibody concentrations that remain high much longer.

The specificity of an antibody is determined by the

variable region

An investigator at a crime scene discovers some body fluid on the victim's clothing. The investigator carefully takes a sample and sends it to the crime lab for analysis. On the basis of the analysis of antibodies, could the crime la determine whether the sample of blood plasma or semen? Explain

yes, the crime lab could determine whether the sample is blood plasma, which contains IgM, IgG, IgD, and IgE, or semen, which contains only IgA.