A&P chapter 20 *

Define immune surveillance.

Immunize surveillance is the constant monitoring of normal tissues by NK cells sensitive to abnormal antigens on the surface of cells.

Describe immunosuppression.

Immunosuppression is the partial or complete reduction of the immune response in a person. It is also induced to enhance the survival of organ transplant recipients.

What is anaphylaxis?

In anaphylaxis, an immune response to circulating antigen stimulates mast cells throughout the body to release chemicals that prompt the inflammatory response.

Describe inflammation.

Inflammation, also called the inflammatory response, is a localized response to injury in the body. It is characterized by redness (rubor), swelling(tumor), heat (calor),and pain Dolor). Lost function (function laesa) is also commonly associated with inflammation.

A child falls off her bike and skins her knee. Which form of immunity will be activated immediately?

Innate (nonspecific) immunity will be activated immediately in the child with a skinned knee.

What is the difference between a lymphocyte and lymph?

Lymphocytes are the primary cells of the lymphatic system. These cells respond to pathogens, abnormal body cells, and foreign proteins such as toxins released by bacteria. Lymph is the interstitial fluid the has entered a lymphatic vessel and surrounds lymphocytes.

Explain lymphedema.

Lymphedema is the accumulation of interstitial fluids the results from blocked lymphatic drainage. If the condition persists, connective tissues lose their elasticity, and the swelling becomes permanent.

Describe red pulp and white pulp found in the spleen.

Red pulp contains large numbers of red bold cells; white pulp resembles lymphoid nodules and contains lymphocytes.

Define sensitization.

Sensitization is the process by which a B cell prepares to undergo activation after encountering a specific antigen. During sensitization, the the specificcy antigens are brought into the cell where they become bound to Class II MHC proteins. Together, they then appear at the cell surface.

What are the functions of the lymphatic system?

The function of the lymphatic system are to provide immunity (the ability to defend the body against infection, illness,and disease) and to return tissue fluid to the bloodstream.

Provide a plausible explanation for the increased incidence of cancer in the elderly.

The increased incidence of cancer in the elderly may result from a decline in immune surveillance.

How does the integumentary system protect the body?

The integumentary system provide a physical barrier that is the first line of defense in preventing pathogens and toxins from entering body tissues. Skin secretions flush the surface, hair protects against physical abrasion, and the multiple layers of the skin's epithelium create an interlocking barrier.

Name the two large lymphatic vessels into which the lymphatic trunks empty.

The lymphatic trunks empty into the thoracic duct and the right lymphatic duct.

What is the major histocompatibiity complex (MHC)?

The major histocompatibility complex (MHC) is a portion of the chromosome 6 containing genes that control the synthesis of membrane glycoproteins.

Identify the three main classes of lymphocytes.

The tree main classes of lymphocytes are T cells, B cells, and natural killer (NK) cells.

Which two cells coordinate adaptive immunity?

The two cells responsible for coordinating adaptive immunity are T cells and B cells.

Which cells constitute and maintain the blood-thymus barrier?

Thymine epithelial cells in the cortex maintain the blood-thymus barrier.

Define tonsil, and name the five tonsils.

Tonsils are large lymphoid nodules in the walls of the pharynx. The five tonsils are the left and right palatine tonsils, a single pharyngeal tonsil (adenoid), and a pair of lingual tonsils.

Which type of immunity develops when a child is given the polio vaccine?

A child who receives the polio vaccine develops artificially induced active immunity.

A rise in the level of interferons in the body suggests what kind of infection?

A rise in the level of interferons suggests a viral infection.

How do abnormal antigens attached to Class I MHC proteins initiate an immune response?

Abnormal antigens attached to class I MHC proteins of an infected cell are displayed on the surface of the cell's plasma embrace. The recognition of such antigens by CD8 T cells initiates an immune response.

Define allergy and allergen.

An allergy is an inappropriate one excessive immune response to all gen, which is an antigen the triggers and allergic reaction.

Describe the structure of an antibody.

An antibody molecules consist of two parallel pairs of polypeptide chains: a pair of long, heavy chains and a pair of short, light chains. Each chain contains both constant segments and variable segments. The constant segments of the heavy chains form the base of the antibody molecule; the free tips of the two viable segments form the antigen binding sites.

Describe antigenic determinant site.

An antigenic determinant site is the part of the antigen molecule to which an antibody molecule binds.

Describe antigen presentation.

Antigen presentation occurs when an antigen-glycoproteins, or antigen-MHC protein, combination capable of activating T cells appears in a plasma membrane (typically that of a macrophage). T cells sensitive to this antigen are activated if they contact the antigen of the plasma membrane of the antigen-presenting cell.

List the ways that antigen-antibody complexes can destroy target antigens.

Antigen-antibody complexes help to destroy antigens through seven processes: neutralization, prevention of bacterial and viral adhesion, activation of complement, opsonization, attraction of phagocytes, stimulation of inflammation, and precipitation and agglutination.

Define autoimmune disorders.

Autoimmune disorders are diseases that result from the production of antibodies (called autoantibodies) directed against normal substances in the body (self-antigens).

Which cells are responsible for antibody-mediated immunity?

B cells are responsible for antibody-mediated immunity.

Which cells are involved in inflammation?

Basophils and mast cells are involved in inflammation.

Beginning at the trabecular arteries, trace the path of blood through the spleen.

Beginning with the arteries, blood then flows to the central arteries----> capillaries----> reticular tissues of red pulp----> sinusoids----> trabecular veins.

Identify the type of T cell whose plasma membrane contains CD8 markers and the type with CD4 markers.

CD* markers are found on cytotoxic T cells, memory Tc cells, and suppressor T cells; CD4 markers are on all helper T cells.

If NK cells are engaged in immune surveillance, how do cancer cells spread?

Cancer cells can mutate such that either they do not display tumor-specific antigens, or they secrete chemicals that destroy NK cells. This ability to escape detection is called immunological escape.

Define chemotaxis.

Chemotaxis is phagocytes movement in response to attraction to or repulsion from chemical stimuli.

Where are Class I MHC proteins and Class II MHC proteins found?

Class I MHC proteins are in the plasma membranes of all uncleared body cells. Class II MHC proteins are only in the plasma membranes of antigen-presenting cells (APCs) and lymphocytes.

Explain the function of cytokines secreted by helper T cells.

Cytokines secreted by activated T cells aid in coordinating specific and nonspecific defense and regulate cell-mediated and antibody-mediated immunity.

Which cells can be activated by direct contact with virus-infected cells?

Cytotoxic T cells and NK cells can be activated by direct contact with virus-infected cells.

What is the function of lymphatic vessels?

Lymphatic vessels transport lymph from peripheral tissues to venous system.

What is the effect of histamine released by complement system activation?

Histamine release by mast cells and basophils in tissues increases local inflammation, thereby accelerating blood flow to the region.

Which chemicals do mast cells and basophils release when stimulated in an allergic reaction?

Histamines, leukotrienes, and other chemicals that cause pain and inflammation are released when mast cells and basophils are stimulated in an allergic reaction.

Distinguish between innate immunity and adaptive immunity.

Innate immunity is nonspecific and does not distinguish one type of threat from another. Adaptive immunity is specific and protects against particular threats.

How does innate immunity protect us from disease?

Innate immunity protects us using physical barriers such as skin, phagocytes that engulf pathogens, immune surveillance of abnormal cells, interferons to defend from viruses, complement to assist antibodies, inflammation to limit the spread of infection, and fever.

Define interferons.

Interferons are small proteins that are released by activated lymphocytes, macrophages, and cells infected with viruses; they trigger the production of antiviral proteins that interfere with viral replication within tissue cells.

Trace the path of lymph trough a lymph node, beginning at the afferent lymphatic.

Lymph flow through a lymph node: afferent lymphatics----> subcapsular space------>outer cortex-----> deep cortex------> medullary sinus----> efferent lymphatics.

What structure prevents the back flow of lymph in some lymphatic vessels?

Lymphatic valves prevent the back flow of lymph in some lymphatic vessels.

Name the lymphoid tissue that protects epithelial lining the digestive, respiratory, unitary, and reproductive tracts.

Mucosa-associated lymphoid tissue that protects epithelial inning the digestive, respiratory, urinary, and reproductive tracts.

How do NK cells detect cancer cells?

NK cells recognize unusual proteins, called tumor-specific antigens, on the plasma membranes of cancer cells. When these antigens are detected, the NK cells then destroy the abnormal cells.

Define opsonization.

Opsonization is the process by which the coating of pathogens with antibodies and complement proteins makes the pathogens more susceptible to phagocytosis.

What is the function of overlapping endothelial cells in lymphatic capillaries?

Overlapping endothelial cells in lymphatic capillaries act as one-way valves that permit the entry of fluids and solutes but prevent their return to the intercellular spaces.

If you observed a higher-than-normal number of plasma cells in a sample of lymph, would you expect antibody levels in the blood to be higher or lower than normal?

Plasma cells produce and secrete antibodies, so observing an elevated number of plasma cells in the lymph would lead you to expect higher-than-normal antibody levels in the blood.

Which cells produce antibodies?

Plasma cells produce antibodies.

Distinguish between primary and secondary lymphoid tissues and organs?

Primary lymphoid tissues and organs are sites where lymphocytes are formed and mature. Secondary lymphoid tissues and organs are sites where lymphocytes are activated and cloned.

What effect do pyrogens have in the body?

Pyrogens increase body temperature (produce a fever), which can mobilize defenses, accelerate repairs, and inhibit pathogens.

Describe CD markers.

T cell plasma membranes contain proteins called CD (cluster of differentiation) markers. Cells with CD8 markers respond to antigens presented by class I proteins and are on cytotoxic T cells, memory Tc cells, and suppressor T cells. Cells with CD4 markers respond to antigens presented by class II MHC proteins.

Identify the types of phagocytes in the body and differentiate between fixed macrophages and free macrophages.

The body's phagocytes are neutrophils, eosinophils, and macrophages. Fixed macrophages are scattered among connective tissues and do not move; free macrophages are mobile and reach injury sites by migrating through adjacent tissues or traveling in the bloodstream.

Briefly explain the role of complement proteins.

The complement proteins of the complement system interact with each other in chain reactions that ultimately produce activated forms that target bacterial membrane, stimulate, inflammation. Attract phagocytes, or enhance phagocytosis.

What are the properties of adaptive immunity?

The properties of adaptive immunity are specificity, versatility, immunologic memory, and tolerance.

What tissues are involved in lymphopoiesis?

The red bone marrow, thymus, and peripheral lymphoid tissues are involved in lymphopoiesis.

Describe the drainage of the right lymphatic duct and the thoracic duct.

The right lymphatic duct collects lymph from the right side of the body superior to the diaphragm; the thoracic duct collects lymph from the body inferior to the diaphragm and from the left side of the body superior to the diaphragm.

Which would be more affected by a lack of memory B cells and memory T cells: the primary response or the secondary response?

The secondary response would be more affected by a lack of memory cells, which are produced in response to an initial exposure to an antigen during the primary response.

What is the function of the spleen?

The spleen filters the blood; the phagocytes it contains identify and engulf pathogens or infected cells circulating the blood.

Identify the three major types of T cells activated by Class I MHC proteins.

The three major types of T cells activated by class I MHC proteins are cytotoxic T cells, memory Tc cells, and suppressor T cells.

Describe the gross anatomy of the thymus

The thymus I'd pink, grainy organ ranging in weight from 12 g by age 50. A capsule covers the thymus and divides it into two lobes, and fibrous partitions called septa divide the lobes into lobules.

Where is the thymus located?

The thymus is located in the anterior and mediastinum, posterior to the sternum.