After an antigen presenting cell engulfs and degrades a pathogen, it displays fragments complexed with class II MHC molecules on the cell surface. A specific helper t cell binds to a displayed complex via its antigen receptor and an accessory protein called CD4. This interaction promotes secretion of cytokines by the antigen presenting cell. Proliferation of the helper t cell, stimulated by cytokines from both cells gives rise to clone of activated helper t cells with receptors for the same MHC complex. Following proliferation, helper T cells secrete other cytokines which help activate b cells and cytotoxic t cells.

• Chapter 43 The Immune System Quizlet
• The Lymphatic System

After antigen presenting cell engulfs and degrades pathogen it displays fragment with II MHC. A helper t cell that recognizes complex is activated with aid of cytokines secreted from antigen presenting cell. When a b cell with receptors for the same epitope internalizes the antigen it displays an antigen fragment on the cell surface in a complex with a II MHC molecule. T cell binds to b cell, activating it. Activated b cell proliferates and differentiates into memory b cells and plasma cells.

1 Biology 120 J. Greg Doheny Chapter 43 The Immune System The immune system consists of a network of ducts and vessels called the Lymphatic System, and. 38) The following events occur when a mammalian immune system first encounters a pathogen. Medical surgical nursing study guide. Place them in correct sequence and then choose the answer.

9) Salmonella bacterial poisoning can be initiated when A) the microbe survives the acidic environment of the stomach and resists lysosomal degradation in macrophages. B) the chemotactic messengers released by the microbe do not attract sufficient neutrophils to entirely destroy the infection. C) there is a delay in selection of the population of eosinophils that recognize and fight these microbes. D) the microbes release chemical messengers that make them resistant to phagocytosis. E) The combination of foods eaten at the meal reduces the pH of the stomach sufficiently so that ingested microbes are not destroyed.

13) Ancient peoples sought to identify the indicators of inflammation because A) seeing such signs would be cause for their seeking out a healer in their community. B) the presence of the signs of inflammation in a patient could be a condemnation of the healer. C) the ancients probably knew of plant derivatives that could reduce the pain of inflammation.

D) the presence of these signs suggests that healing was taking place; otherwise, the patient would likely die. E) the signs of inflammation served as a caution to keep people away from the patient. 28) B cells have antigen receptors that bind to antigens that are either freely dissolved or present on the surface of invading/foreign cells. T cells have antigen receptors that A) are active only in lymph nodes. B) bind only to antigens present on the surface of the invading/foreign cells. C) bind only to freely dissolved antigens in the plasma. D) bind to antigens presented on major histocompatability complexes by host cells.

E) bind to antigens that are either freely dissolved or present on the surface of invading/foreign cells. 48) Select the pathway that would lead to the activation of cytotoxic T cells.

A) B cell contact antigen → helper T cell is activated → clonal selection occurs B) body cell becomes infected with a virus → new viral proteins appear → class I MHC molecule-antigen complex displayed on cell surface C) self-tolerance of immune cells → B cells contact antigen → cytokines released D) complement is secreted → B cell contacts antigen → helper T cell activated → cytokines released E) cytotoxic T cells → class II MHC molecule-antigen complex displayed → cytokines released → cell lysis. 50) Arrange these components of the mammalian immune system as it first responds to a pathogen in the correct sequence.

Pathogen is destroyed. Lymphocytes secrete antibodies. Antigenic determinants from pathogen bind to antigen receptors on lymphocytes. Lymphocytes specific to antigenic determinants from pathogen become numerous. Only memory cells remain. A) I → III → II → IV → V B) III → II → I → V → IV C) II → I → IV → III → V D) IV → II → III → I → V E) III → IV → II → I → V.

66) A diseased patient is exposed to an unknown agent while out of the country. The patient's blood is found to have a high proportion of lymphocytes with CD8 surface proteins in her blood, a likely result of A) the patient having encountered a bacterial infection which elicited CD8+ T cells. B) the disease having been caused by a multicellular parasite, such as can be encountered in polluted water sources.

C) the CD8 proteins having been discharged from these lymphocytes to lyse the infected cells. D) a viral infection eliciting proliferation of CD8+ cytotoxic T cells. E) the CD8 proteins having 'marked' the surface of cells that accumulate after the infection is over and signal patient recovery.

67) The switch of one B cell from producing one class of antibody to another antibody class that is responsive to the same antigen is due to A) mutation in the genes of that B cell, induced by exposure to the antigen. B) the rearrangement of V region genes in that clone of responsive B cells. C) a switch in the kind of antigen-presenting cell that is involved in the immune response. D) a patient's reaction to the first kind of antibody made by the plasma cells. E) the rearrangement of immunoglobulin heavy-chain C region DNA.

68) The number of MHC protein combinations possible in a given population is enormous. However, an individual in that diverse population has a far more limited array of MHC molecules because A) the MHC proteins are made from several different gene regions that are capable of rearranging in a number of ways. B) MHC proteins from one individual can only be of class I or class II. C) each of the MHC genes has a large number of alleles, but each individual only inherits two for each gene. D) once a B cell has matured in the bone marrow, it is limited to two MHC response categories.

E) once a T cell has matured in the thymus, it can only respond to two MHC categories. 69) A bone marrow transplant may not be appropriate from a given donor (Jane) to a given recipient (Jane's cousin Bob), even though Jane has previously given blood for one of Bob's needed transfusions, because A) even though Jane's blood type is a match to Bob's, her MHC proteins may not be a match. B) a blood type match is less stringent than a match required for transplant because blood is more tolerant of change. C) for each gene, there is only one blood allele but many tissue alleles. D) Jane's class II genes are not expressed in bone marrow. E) Bob's immune response has been made inadequate before he receives the transplant. 72) An immune response to a tissue graft will differ from an immune response to a bacterium because A) MHC molecules of the donor may stimulate rejection of the graft tissue, but bacteria lack MHC molecules.

B) the tissue graft, unlike the bacterium, is isolated from the circulation and will not enter into an immune response. C) a response to the graft will involve B cells and a response to the bacterium will not.

D) a bacterium cannot escape the immune system by replicating inside normal body cells. E) the graft will stimulate an autoimmune response in the recipient. 76) The ability of some viruses to remain inactive (latent) for a period of time is exemplified by A) influenza, a particular strain of which returns every 10-20 years. B) herpes simplex viruses (oral or genital) whose reproduction is triggered by physiological or emotional stress in the host.

C) Kaposi's sarcoma, which causes a skin cancer in people with AIDS, but rarely in those not infected by HIV. D) the virus that causes a form of the common cold, which recurs in patients many times in their lives. E) myasthenia gravis, an autoimmune disease that blocks muscle contraction from time to time. Mutant fruit flies that make only one antimicrobial peptide were tested for survival after infection with Neurospora crassa fungi or with Micrococcus luteus bacteria. 81) The results shown in the graphs support the hypothesis that A) adding the defensin gene to such mutants protects them from fungal infection. B) adding the drosomycin gene to such mutants protects them from fungal infection.

C) wild-type flies with the full set of genes for antimicrobial peptides are highly susceptible to these infective agents. D) the presence of any single antimicrobial peptide protects against both infective agents. E) even the wild-type flies rarely, if ever, survive for five days. 86) In Cases 1 and 2 in the table, the mothers would be able, if needed, to supply blood to the newborn even seven to nine months after birth; the same would not be true for Case 3. This is because A) the fetus in Case 3 would provoke an immune response in the mother that would carry over after the birth.

B) the newborn in Case 3 would soon be able to make antibodies to the B antigen of the mother. C) newborn children, until about age 2, do not make appreciable antibodies, except against Rh+ antigen.

D) passive immunity would have worn off for the third newborn, but not for the other two. E) this difference is based on which of the mothers has been nursing her children, not on blood antigens. 88) After a long and cold winter, Jim was excited to start exploring the woods behind his new home.

His first adventure included exposure to poison ivy without any reaction. A month later, though, a second walk through the woods was not so great, since two days later Jim had a terrible rash that lasted for weeks. The fact that the rash took two days to develop indicates that this immune response was an example of A) humoral immunity. B) cell-mediated immunity. C) innate immunity. D) the activation of Toll-like receptors. E) the activation of the complement system.

An otherwise healthy student in your class is infected with EBV, the virus that causes infectious mononucleosis. The same student had already been infected when she was a child, at which time she had merely experienced a mild sore throat and swollen lymph nodes in her neck. This time, though infected, she does not get sick.

90) The EBV antigen fragments will be presented by the virus-infected cells along with A) complement. B) antibodies. C) class I MHC molecules. D) class II MHC molecules. E) dendritic cells. Immunodeficiencies can be genetic in origin, and two examples are Bruton's agammaglobulinemia, an X-linked disorder, and DiGeorge syndrome, caused by a deletion from chromosome 22. Bruton's disorder results in underdeveloped B cells, whereas DiGeorge syndrome results in a missing or seriously underdeveloped thymus.

91) Select the description that likely indicates a child with Bruton's disease. A) baby girl Denise, with low level of antibody response to streptococcal infection B) baby boy John, with immature T cells, missing CD4 receptors C) baby boy Jeff, with no plasma cells following infection by bacterial pneumonia D) baby girl Susan, with no evidence of a thymus gland E) baby boy Matt, with very low circulating antigens. Immunodeficiencies can be genetic in origin, and two examples are Bruton's agammaglobulinemia, an X-linked disorder, and DiGeorge syndrome, caused by a deletion from chromosome 22.

Bruton's disorder results in underdeveloped B cells, whereas DiGeorge syndrome results in a missing or seriously underdeveloped thymus. 92) Bruton's disorder will likely include A) the failure of heavy-chain gene rearrangement in B cells. B) the failure to incorporate CD4 receptors into cell membranes. C) an underexpression of the gene for the β chain of the T cell receptor.

D) an underexpression of the gene for the CD8 receptor molecule. E) the inability of the bone marrow cells to interact with MHC molecules. Immunodeficiencies can be genetic in origin, and two examples are Bruton's agammaglobulinemia, an X-linked disorder, and DiGeorge syndrome, caused by a deletion from chromosome 22.

Chapter 43 The Immune System Quizlet

Bruton's disorder results in underdeveloped B cells, whereas DiGeorge syndrome results in a missing or seriously underdeveloped thymus. 93) Assume that a DGS-like phenotype was produced in a specific 'gene-knockout' mouse, one lacking expression of HA3, a Hox gene known to be involved in developmental regulation in the mouse. The phenotype of the HA3 knockout can be ascertained by A) a bone marrow biopsy. B) an assay for environmental agents known to cause birth defects. C) a chest X-ray. D) the measurement of the proportion of CD4 cells to total lymphocytes.

The Lymphatic System

E) an autopsy examination of the adrenal glands. 96) Which statement best describes the difference in responses of effector B cells (plasma cells) and cytotoxic T cells? A) B cells confer active immunity; cytotoxic T cells confer passive immunity. B) B cells kill pathogens directly; cytotoxic T cells kill host cells. C) B cells secrete antibodies against a pathogen; cytotoxic T cells kill pathogen-infected host cells. D) B cells carry out the cell-mediated response; cytotoxic T cells carry out the humoral response.

E) B cells respond the first time a pathogen is present; cytotoxic T cells respond subsequent times.