chapter 11

Question 1

what is the job of antibodies?

Answer 1

• lets the body know when it needs to mobilize the immune response
  
  • has to recognize substances/cells that need to be eliminated
  • and to be recognized by other components of the immune system

Question 2

what does the term antigen refer to?

Answer 2

• what antibodies recognize

Question 3

antibodies have a Y shaped structure containing?

Answer 3

• 2 heavy chains and 2 light chains that are linked by disulfide bonds
  
  • the “top” ends of the Y shaped structure (the part with both the heavy and light chains) have a hypervariable antigen-recognizing area, and tehr est of the antibody structure can be recognized by other cells of the immune system

Question 4

the specific site on an antigen that is recognized by an antibody is known as the?

Answer 4

• epitope

Question 5

what is the primary job of T cells?

Answer 5

• directly attack compromised/foreign cells or mobilize responses to them based on antigen fragments that are presented by major histocompatability complex (MHC) class I and II

Question 6

what is MHC class I?

Answer 6

• a protein expressed on the plasma membrane of all nucleated cells that is unique in each individul
• its job is to receive fragments of the proteins being expressed inside of a cell and to present themon the outside of the cell as antigens that T cells can respond to
• if all is well, T cells will not respond because the “antigens” in question are just normal pieces of cellular machinery and T cells that would inappropriately respond to such stimuli were eliminated during their maturation process
• however, cells infected by viruses can present viral antigens on MHC class I and incipient tumor cells are likely to fail to present appropriate proteins

Question 7

what is MHC class II?

Answer 7

• expressed in a smaller range of cells: primarily macrophages, macrophage like cells, such as dendritic cells and B cells
• serves as a source of external information
  
  • ex. when a macrophage consumes a microbe, some fragments of it will be displayed in a complex formed with MHC class II on the cell membrane. this complex is recognized by helper T cells and a larger immune response then ensues

Question 8

the process by which cells present antigens on their membranes is known as?

Answer 8

• antigen presentation

Question 9

what is immunohistochemistry or immunostaining?

Answer 9

• western blotting and enzyme-linked immunosorbent assays (ELISA) is used to visualize specific proteins
  
  • key is that the protein of interest serves as an antigen that is visualized after it reacts with an antibody that has been modified so that it can be visualized using fluorescence or staining with an appropriate dye

Question 10

what is the innate immune response?

Answer 10

• the non-specific immune response
• the component of the immune system that mounts a broad-spectrum defense against threats, but does not involve the recognition of specific foreign bodies and molecules

Question 11

that innate immune response can be split into?

Answer 11

• the non-cellular and cellular components

Question 12

what is the non-cellular component of the innate immune response?

Answer 12

• includes anatomical barriers and signalling molecules such as cytokines and complement proteins

Question 13

what is the cellular component of the innate immune response?

Answer 13

• includes a range of white blood cell types (leukocytes) that play various roles in responding to threats
• the various components of the innate immune system can act independently or be coordinated in the process od inflammation

Question 14

what are the WBC’s and their roles?

Answer 14

• neutrophils- most common type. their main role is to phagocytose invading bacteria, and can be thought of as the first responders to infection
• lymphocytes- next most common type which cotnain B cells, T cells and natural killer cells. B and T cells are involed in the adaptive immune response. NK cells are best known for killing virally infected cells, and detecting and controlling early signs of cancer. As well as protecting against disease, specialized NK cells are also found in the placenta and may play an important role in pregnancy
• monocytes- next common- they travel to various tissues in the body and then differentiate into macrophages or dendritic cells
• eisonophils- target parasitic infections
• basophils- involved in allergic responses
• mast cells- function similarly to basophils but tend to be located specifically in mucous membranes and connective tissue

Question 15

what are phagocytes?

Answer 15

• refers to any cell that engages in phagocytosis or the englufment and destruction of one cell by another
• phagocytes include neutrophils, monocytes, macrophage, dendritic cells, and mast cells

Question 16

what is complement in the innate immune system

Answer 16

• refers to a signalling cascade of many proteins that function to destroy the pathogens in question (opsonization), to recruit phagpcytes to destroy the pathogens in question, and/or to initiate the inflammatory process

Question 17

what are cytokines?

Answer 17

• a broad and diverse class of signalling protiens that are involved in coordinating the immune response and inflammation

Question 18

what are interferons?

Answer 18

• subset of cytokines that are best known for having antiviral effects
• they are released by infected cells when recpetors located in the cytoplasm or p.m. recognize certain microbial biomolecules
• once released, they have 2 major effects: they signal nearby cells to prepare themselves to defenf against a viral infection and they upregulare the overall immune response

Question 19

what is inflammation?

Answer 19

• a reponse to cellular injury ot the presence of pathogens that results in the clinically noticeable signs/symptoms of redness, heat, pain, and swelling
• the inflammatory cascade ultimately results in vasodilation in the affected area and increased permeability of blood vessels
• vasocilation results in increased blood flow and increased permeability results in plasma being able to migrate from the blood into the affected tissue

Question 20

what is the adaptive immune system?

Answer 20

• the part of the immune system that “learns” to recognize specific invaders/pathogens

Question 21

what re B cells?

Answer 21

• antibodies because the basic job of B cells is to learn to recognize antigens and to secrete large amounts of antibodies in reponsse
• after being produced in the bone marrowm they move to lymphatic tissue
• before tehy have “seen” an antigen, they are known as naïve, through random recombination, naïve B cells express receptors for many different antigens, and some may never encounter a matching antigen at all
• once a B cell is presented with a matching antigen, it proliferates in a process knwon as clonal selection
• activated B cells either become plasma cells or memory cells
• involved in humoral immunity which refers more specifically to the immune effects of antibodies, whereas T cells are involved in cell-based immunity

Question 22

what are T cells?

Answer 22

• cell-mediated branch of the adaptive immune system
• respond to the MHC classes I and II
• cytotoxic CD8⁺ T cells recognize and destroy cells that present abnormal MHC class I proteins by injecting substances that induce apoptosis
• CD4⁺ T cells respond to cells presenting MHC class II by secreting special cytolines that recruit other immune cells to mount a reaction

Question 23

what are memory T cells and suppressor T cells?

Answer 23

• “remember” antigens that they have been exposed to
• reduce the immune response once an infection has been adequately dealt with and to help prevent self-reactivity, which can cause autoimmune diseases

Question 24

where are T cells produced and mature?

Answer 24

• produced in the bone marrow, mature in the thymus
• the vast majority of immature T cells are discarded
• T cells that fail to respond appropriately to MHC class I and II are eliminated through positive selection
• T cells that over react- reactive against self cells- are eliminated through negative selection

Question 25

organs important to the anatomy of the immune system:

Answer 25

• bone marrow- WBC are produced here
• spleen- contributes to the circulatory system by breaking down senescent red blood cells and holding a reserve of blood, but the area of the white pulp contributes to the immune system. it is rich in lymphocytesnand a site for the activation of B cells. also coordinates the immune response
• thymus where T cells mature

Question 26

what is the lymphatic system?

Answer 26

• part of the circulatory and immune systems
• drains interstitial fluid from the space surrounding the cells of the tissue
  
  • lymph capillaries collect this fluid and empty into lymph vessels which converge into lymphatic ducts which then empty into the circulatory system

Question 27

what are lymph nodes?

Answer 27

• organized clusters of lymphatic system that can be thought of as filtration points for the lymphatic fluid where reservoirs of B and T cells are stored

Question 28

what are key organs of the lymphatic system?

Answer 28

• the thymus
• spleen
• red bone marrow

Question 29

what are the main functions of the lymphatic system?

Answer 29

• maintenance of fluid balance
• transport of other mateirals from the extracellular space back into the bloodstream
• lipid transport from the digestive system into the bloodstream
• production and maturation of lymphocytes

Question 30

what are allergies?

Answer 30

• occurs when the immune system mounts a response against some exogenous stimulus that is actually harmless

Question 31

what are autoimmune disorders?

Answer 31

• occur when the body mistakenly recognizes self cells as being non-self and mounts an immune response against them