Human Anatomy & Physiology: Review Questions - Immunity Flashcards

All of the following are considered innate body defenses except.

C) Antibodies

The process by which neutrophils squeeze through capillary walls in response to inflammatory signals is called:

A) Diapedesis

Antibodies released by plasma cells are involved in:

D) All of the above

Which of the following antibodies can fix complement?

D) IgG,

Which antibody class is abundant in body secretions?

A) IgA

D) Haptens

B) B Lymphocytes

Cells that can directly attack target cells include all of the following except:

C) Helper T cells

Which of the following is involved in the activation of a B cell?

D) cytotoxic T cell

The cell type most often invaded by HIV

D) Helper T cell

complement fixation promotes all of the following except

D) interferon release

1. Phagocyte
(b) Neutrophil
(g) Macrophage

2. Release histamine
(d) Mast cell
(i) Basophil

3. Release perfoins
(a)Natural killer cell
(e)Cytotoxic T cell

4. Lymphocyte
(a)Natural killer cell
(e)Cytotoxic T cell
(f)B cell
(h)Helper T cell

5. Effector cells of adaptive immunity
(e)Cytotoxic T cell
(h)Helper T cell

6. Antigen-presenting cell
(c)Dendritic cell
(f)B cell
(g)Macrophage

Besides acting as mechanical barriers, the skin epidermis and mucosae of the body have other attributes that contribute to their protective roles.
Cite the common body locations and the importance of mucus, lysosome, keratin, acitd ph, and cilia.

Mucosae are found on the outer surface of the eye and in the linings of all body cavities open to the exterior,such as the digestive, respiratory, urinary, and reproductive tracts. The epidermis is the outermost covering of the body surface. Mucus provides a sticky mechanical barrier that traps pathogens.

Lysosyme, an enzyme that destroys bacteria, is found in saliva and lacrimal fluid.

Keratin, a tough waterproofing protein in epithelial membranes, presents a physical barrier to microorganisms on the skin. It is resistant to most weak acids and bases and to bacterial enzymes and toxins.

The acid pH of skin secretions inhibits bacterial growth. Vaginal secretions and urine (as a rule) are also very acidic. Hydrochloric acid is secreted by the stomach mucosa and acts to kill pathogens.

Cilia of the upper respiratory tract mucosae sweep dust and bacteria-laden mucus superiorly toward the mouth, restraining it from entering the lower respiratory passages.

(pp. 767-768)

Explain why attemps at phagocytosis are not always successful; cite factors that increase the likelihood of success

Attempts at phagocytosis are not always successful because to accomplish ingestion, the phagocyte must first adhere to the particle. Complement proteins and antibodies coat foreign particles, providing binding sites to which phagocytes can attach, making phagocytosis more efficient.

(p. 768)

What is complement? How does it cause bacterial lysis? what are some of the other roles of complement?

The term complement refers to a heterogenous group of at least 20 plasma proteins that normally circulate in an inactive state. Complement is activated by one of two pathways (classical or alternative) involving the plasma proteins. Each pathway involves a cascade in which complement proteins are activated in an orderly sequence leading to the cleavage of C3. Once C3b is bound to the target cell's surface, it enzymatically initiates the remaining steps of complement activation, which incorporates C5 through C9 (MAC) into the target cell membrane, ensuring lysis of the target cell.

Other roles of complement include opsonization, inflammatory actions such as stimulating mast cells and basophils to release histamine (which increases vascular permeability), and attracting neutrophils and other inflammatory cells to the area.

(pp. 774-775)

Interferons are referred to as antiviral proteins. What stimulates their production, and how do they protect unifected cells? what cells of the body secrete interferons?

Interferons are secreted by virus-infected cells. They diffuse to nearby cells where they interfere with the ability of viruses to multiply within these cells. Cells that form interferon include macrophages, lymphocytes, and other leukocytes.

(pp. 773-774)

Differeniate between humoral and cell mediated adaptive immunity.

Humoral immunity is provided by the antibodies in the body's fluids. Cell-mediated immunity is provided by non-antibody-producing lymphocytes, i.e., T cells.

(p. 776)

Although the adaptive immune system has two arms, it has been said, "no T cells, no immunity" Explain

Cytokines released by helper T cells help to amplify and regulate both the humoral and cellular immune responses as well as the innate defense responses.

(pp. 791-792)

Define immunocompetence and self-tolerance. How is self-tolerance achieved?

Immunocompetence is the ability of the immune system's cells to recognize foreign substances (antigens) in the body by binding to them. Acquisition is signaled by the appearance of a single, unique type of cell surface receptor protein on each T or B cell that enables the lymphocyte to recognize and bind to a specific antigen.

(p. 777)

Differentiate between a primary and a secondary immune response. Which is more rapid and why?

A primary immune response results in cellular proliferation, differentiation of mature effector and memory lymphocytes, and the synthesis and release of antibodies—a series of events that takes 3 to 6 days. The secondary immune response results in huge numbers of antibodies flooding into the bloodstream within hours after recognition of the antigen, as well as an amplified cellular attack. Secondary responses are faster because the immune system has been primed to the antigen and sizable numbers of sensitized memory cells are already in place.

(pp. 780-781)

Define antibody. Using an appropriately labeled diagram, describe the structure of an antibody monomer. Indicate and label variable and constant regions, heavy and light chains

Antibodies are proteins secreted by plasma cells in response to a specific antigen, and they are capable of binding to that antigen. See Fig. 21.14 for a look at basic antibody structure.

(p. 783)

What is the role of the variable regions of an antibody? Of the constant regions?

The variable region of an antibody is the portion of the antibody that binds to the different antigens. There is a different variable region for each different antigen. The constant region of the antibody is used to separate the antibodies into the different classes. There are only five different constant regions and all members of a specific antibody class have the same constant region.

(p. 783)

Name the five antibody classes and describe where each is more likely to be found in the body

The antibody classes and their probable locations in the body include the following:

Class IgD—virtually always attached to B cells; B cell receptor

Class IgM—monomer attached to B cells; pentamer free in plasma (during primary response)

Class IgG—in plasma

Class IgA—some in plasma, most in secretions such as saliva, tears, intestinal juice, and milk

Class IgE—secreted by plasma cells in skin, mucosae of gastrointestinal and respiratory tracts and tonsils

(p. 784; Table 21.3)

How do antibodies help defend the body?

Antibodies help defend the body by complement fixation, neutralization, agglutination, and precipitation. Complement fixation and neutralization are most important in body protection.

(pp. 784-785)

Do vaccines produce active or passive humoral immunity? Explain your answer. Why is passive immunity less satisfactory?

Vaccines produce active humoral immunity because most contain dead or extremely weakened pathogens that have the antigenic determinants necessary to stimulate the immune response but are generally unable to cause disease. Passive immunity is less than satisfactory because neither active antibody production nor immunological memory is established.

(pp. 781-782)

Describe the process of activation of a CD4 T cell

Activation of CD4 cells involves both antigen binding and co-stimulation. The CD4 cells bind only to antigen linked to class II MHC proteins, typically found on the surface of antigen-presenting cells (APCs). Before a CD4 cell can proliferate and form clones, it has to recognize one or more co-stimulatory signals; this involves binding to yet another surface receptor on the APC and the reception of cytokines, such as interleukins.

(pp. 789-790)

Describe the specific roles of helper, regulatory, and cytotoxic T cells in normal cell mediated immunity

Helper T cells function to chemically or directly stimulate the proliferation of other T cells and of B cells that have already become bound to antigen. Suppressor T cells function to temper the normal immune response by dampening the activity of both T cells and B cells by releasing cytokines that suppress their activity. Cytotoxic T cells function to kill virus-invaded body cells and cancer cells and are involved in rejection of foreign tissue grafts.

(pp. 791-792)

Name several cytokines and describe their role in the immune response.

Cytokines are soluble glycoproteins released by activated T cells. They enhance the defensive activity of T cells, B cells, and macrophages.

Specific cytokines and their role in the immune response are summarized in Table 21.4.

Define hypersensitivity. List three types of hypersensitivity reactions. For each, note whether antibodies or T cells are involved and provide two examples.

Hypersensitivity is an antigen-induced state that results in abnormally intense immune responses to an innocuous antigen. Immediate hypersensitivities include anaphylactic shock and atopy. Subacute hypersensitivities include cytotoxic and immune complex hypersensitivities. All of these involve antibodies. Delayed hypersensitivities include allergic contact dermatitis and graft rejection. These hypersensitivities involve T cells.

(pp. 797-799)

What events can result in autoimmune disease?

Autoimmune disease results from changes in the structure of self-antigens, ineffective or inefficient lymphocyte programming, and by cross-reaction of antibodies produced against foreign antigens with self-antigens.

(p. 799)

What accounts for the declining efficiancy of the immune system with age?

Declining efficiency of the immune system with age probably reflects genetic aging.

(p. 799)

a. Jenny has severe combined immunodeficiency disease (SCID), in which T cells and B cells fail to develop. At best there are only a few detectable lymphocytes. If left untreated, this condition is fatal.

b. Jenny's brother has the closest antigenic match, as both children are from the same parents.
c. Bone marrow transplant using umbilical cord stem cells is the next best chance for survival. It is hoped that by replacing marrow stem cells, the populations of T cells and B cells would approach normal.

d. Epstein-Barr virus is the etiologic agent of infectious mononucleosis, usually a self-limiting problem with recovery in a few weeks. Rarely, the virus causes the formation of cancerous B cells—Burkitt's lymphoma.

e. SCID is a congenital defect in which there is a lack of the common stem cell that develops into T cells and B cells. AIDS is the result of an infectious process by a virus that selectively incapacitates the CD4 (helper) T cells. Both result in a severe immunodeficiency that leaves the individual open to opportunistic pathogens and body cells that have lost normal control functions (cancerous).

Some people with a deficit of IgA exhibit recurrent respiratory tract infections. Explain this observation.

If there is a deficit of IgA, which is a secretion of antibodies, it means that the body cannot fight off any unwanted pathogens and that's the reason behind the reoccurring infections

Capillary permeability increases and plasma proteins leak into the interstitial fluid as part of the inflammatory process. Why is this desirable?

It is desirable because when there is an injury, the clotting proteins in the interstitial fluids forms a gel like fibrin mesh that forms a scaffold for permanent repair. This isolates the injured area and prevents the spread of bacteria and other harmful agents to the surrounding tissues

Costanza was picking grapes in her father's arbor when she felt a short prickling pain in her finger. She ran crying to her father, who removed an insect stinger and calmed her with a glass of lemonade. Twenty minutes later Costanza's finger was red, swollen, and throbbing where she had been stung. What type of immune response was she exhibiting? What treatment would relieve her discomfort?

The type of immune response that Costanza is exhibiting is known as anaphylactic shock. Epinephrine is the drug of choice to reverse these histamine mediated affects

Caroline, a pregnant 29 year old woman who is HIV positive and has no signs of AIDS. Which of Caroline's cells are infected by the virus and why can this be devastating to the immune system?

Although Caroline's TH cells are the main HIV targets, other cells displaying CD4 protein are at risk as well. It is devastating because, in time, a profound deficit of B cell and cytotoxic cell function develops, sending the whole immune system into disorder