Chapter 43 The Immune System Answers
BIO152
Chapter 43 – The Immune System
1. Describe the function of the immune system.
Function: protect body from pathogens + foreign objects, destroy infected or malignant cells, and remove cellular debris.
System includes: thymus, spleen, lymph nodes and tissues, stem cells, white blood cells, antibodies.
2. Compare innate and acquired immunity, and how they differ in terms of how quickly they attack a pathogen, and how they recognize a pathogen.
Innate immunity- immediate defense upon infection and foundation for adaptive immunity
-rapid response
-distinguishes non-self from self- molecular recognition. then, receptor molecules bind specifically to molecules from foreign cells or viruses.
-recognition of traits shared …show more content…
by broad ranges of pathogens w/ small set of receptors.
Acquired immunity(adaptive)- activated when innate immune respond to the infection
-slower response
-has different receptors for each of particular part of a particular molecule in a particular pathogen.
-recognition of trails specific to particular pathogens w/ many receptors
Innate immunity defenses found in human (vertebrates) (goals 3-10):
3. Describe each barrier defense, where each is located in the body, and how each works to combat infections.
Barrier defense-
-location: skin, mucous membranes in digestive, reparatory, urinary, and reproductive tracts.
-function to combat infections: -produce mucus- for defense by trapping microbes and other particles. ex. lungs -saliva/tears/mucous secretions- provide a washing action that prevents fungi and bacteria dwelling on our skin -creates hostile environment to protect immune system- ex. lysozyme in tears/saliva kills most of the bacteria near that area
4. Explain the role of Toll-like receptors (TLRs) in combating infections, including what types of cells typically have TLRs, and what happens when pathogens bind TLRs.
Toll-like receptors (TLRs)- recognizes a molecular pattern or characteristic on certain pathogens -ex. lipopolysaccharide and flagellin are bacteria found in fungi and viruses. -TLR detects these- response factors
-then, phagocyte cells engulf them- in vacuoles
-vacuoles fuses with lysozyme to destruct these pathogens. -produce gases in lysozyme with poison -lysozyme and other enzymes inside vacuoles can degrade pathogens
5. Define phagocytosis, and explain how phagocytes combat pathogens. Name the four major types of phagocytes found in humans, where the normally reside in the body, and their role in combating pathogens.
phagocytosis- engulfing pathogens for destruction
4 major types of phagocytes in humans:
1. Neutrophils where: circulate in the blood and travel into tissues role: phagocyte
-they form pus(dead phagocytes)
2. Macrophages: "big eaters" where: migrate throughout body, others reside permanently in organs + tissues role: phagocyte - secrete cytokines- calls for help -attract Neutrophils
3. Dendritic cells: where: mainly tissues like skin, places where it contact the environment role: eat and present antigens
4. Eosinophils: where: often found beneath mucosal surfaces role: low phagocytic activity, help kill parasites, worms
6. Explain what types of cells are targeted and destroyed by natural killer cells.
-detect abnormal array of surface proteins- that has virus-infected + cancerous cells.
-if detected- they kill invaders by releasing chemicals
7. Explain how interferons combat pathogens, where they originate, and how they function to combat pathogens.
interferons- proteins that provide innate defense by interfering with viral infections -ex. virus-infected body cells produce- interferons function: let other cell know there is infection + stop the spread of the virus in the body -ex. hepatitis c
8. Describe the role of complement proteins in innate immunity, when and where they are present, where they originate, where they act, and what they combat.
complement protein- about 30 proteins in blood plasma combat: bind + lyse (burst) pathogens originate: made by liver when: they can be triggered by cytokines of infection; cascading effect
9. Describe the inflammatory response, including the four characteristics of inflammation
-characteristics: redness, heat, swelling, and pain
-inflammatory response- the changes brought about by signaling molecules released upon injury or infection
10. (rubor, tumor, calor, dolor), how inflammation is triggered, and how it affects blood vessels of the infected tissue, the effect on neutrophils. (Everything in Figure 43.8 – important!) figure 43.8
mast cells- found in connective tissue
blood vessels: vasodilatation occur- allowing more blood to flow to the damaged tissue -& increased permeability of the blood vessels
11. Know how two types of cells found in your tissues that can trigger inflammation, the chemical messengers they release, and the results of sending these chemical messengers. (Figure 43.8 – important!)
-mast cells and macrophages triggers inflammation - chemical messengers: histamine & cytokines
roles of chemical messengers:
- cause vasodilatation
- attracts Neutrophils from capillaries (which can phagocytosis cell debris & heal tissue)
12. Define antigens, epitope, and antigens receptors.
antigens- found on the surface of pathogens -usually foreign + large molecule that's either protein or polysaccharides -trigger production of antibodies when bonded with a antigen receptors
epitope (antigenic determinants)- parts of antigen; it connects to antigen receptors. -it predicts with type of antibody should be made depending on the shape -on the same antigen, it has multiple epitope ex. ONE antigen can trigger to make different antibody ie. antibody A, B, C shown above
antigen receptors- protein located on immune cells that has a specific biding site for antigen -detects antigens from pathogens -there's various types of antigen receptors
13. Describe the antigen receptors found on the surface of Bone marrow lymphocytes (also know as B cells), and the result when they bind antigen.
B cells:
-Y-shaped molecule
-has 4 polypeptide chains: 2 identical heavy chains and 2 identical light chains.
Binding:
-attaches to epitopes of antigen
-activate antibody to circulate in body fluids
-antigen receptors -> secrete antibody/immunoglobulin (they come off) -difference: secreted rather than membrane bonded
-works like a lock and key
-the antibodies can fit into antigens located on the pathogen or free antigens floating
14.
Describe the antigen receptors on the surface of T lymphocytes (also known as T cells), and the result when they bind antigen.
T cells:
-2 polypeptide chains: alpha and beta chain
- variable(v) regions- antigen-biding site
-constant (c) region- the main body of the antigen receptor
Binding:
-T-cells only bind to antigen that are presented on the surface of host cell
15. Describe the protein structure and function of an antibody/immunoglobulin, and where the variable (V) and constant (C) regions are found.
-structure: antibody/immunoglobulin formed from the antigen receptors on the B Cell -turned into soluble structure rather than membrane bonded
-function: bind to antigens on the pathogens of FREE floating antigens
- structure: variable(v) regions- amino acids are different in each B cell constant (c) region- amino acids are constant
-function: bind to host cell's MHC and antigen fragments at antigen presentation
16. Explain the function of the MHC molecules, and their role in antigen presentation.
-MHC molecule- host protein that displays the antigen fragments on the cell
surface
-pathogen infects or takes over host cell
-host cell cleave antigen into smaller peptides- makes antigen fragments
-binds antigen fragment on- MHC molecule inside the cell
-antigen presentation- display the antigen fragment in a exposed groove of the MHC protein
-T cell antigen receptor recognize and bonds- adaptive immune response
17. Explain how the particular structure of a lymphocyte’s antigen binding site forms during development using gene rearrangement.
Variable(v) region- shuffled; cut + pasted randomly this allows for millions of different variable regions for the BCR
18. Explain why the antigen receptors of lymphocytes are tested for self-reactivity during development, and what happens to cells that are self-reactive.
-In bone marrow, they make sure they don't attack self
-if it's self-reactive- kills itself by apoptosis
19. Describe the role of clonal selection (Figure 43.14) in the immune response.
clonal selection- antigen selects which lymphocyte(different versions of b or t cells) & clone through proliferation(mitosis)
- activated by antigen binding to matching antigen receptor
-once attached + activated, T cell undergoes multiple cell division (clone) -daughter cells either become Effector Cells or Memory Cells.
20. For B cells, distinguish between the function of effector cells (plasma cells) and memory cells, and when each are produced after exposure to antigen. Describe how plasma cells help combat an infection.
Effector Cells- short-lived cells- effect immediately -In B cells- plasma cells secretes antibodies from antigen receptor Memory Cells- long-lived cells- saved until later -It can respond rapidly, when exposure to same antigen in the body later in the time
21. Describe the cellular basis for immunological memory, know why vaccines work (secondary immune responses), how vaccinations work, and the example of smallpox.
immunological memory: responsible for the long-term protection that a prior infection or vaccination provides against many disease. -if you survive infection, you'll be immune to it forever
primary immune response: first exposure to a pathogen, get symptoms, feel sick. -Takes 10-17 days after the initial exposure; body makes lot of antibodies from effector cells from cloning -also stores memory cells for later secondary immune response: second exposure to the same pathogen, no symptoms, faster, more efficient response -memory cells from primary immune response- enable rapid formation of clones of thousand of effector cells
why/how vaccination works:
-inject patients w/ weakened viruses (measles, polio, flu) -from this, our body makes: memory B cells -> protect us from future exposure to the same pathogen
example smallpox:
-Edward Jenner: injected ppl w/ cowpox -from this people made memory cells against smallpox
-so in general, if you inject the body with small amount of pathogen/virus, our body will make memory cells & antibodies more quickly, which will prevent us to catch the same pathogen/virus again
22. Describe the roles of helper T cell in both humoral and cell-mediated immunity, and the role of an antigen-presenting cell in helper T cells function.
-A type of T cell that, when activated, secretes cytokines that promote the response of B cells (humoral response) and cytotoxic T cells (cell-mediated response) to antigens.
-Antigen-presenting cell: A cell that upon ingesting pathogens or internalizing pathogen proteins generates peptide fragments that are bound by class II MHC molecules and subsequently displayed on the cell surface to T cells. Macrophages, dendritic cells, and B cells are the primary antigen-presenting cells.
23. For T cells, distinguish between the function of effector cells (cytotoxic T cells) and memory cells, and when each are produced after exposure to antigen. Describe how cytotoxic T cells help combat an infection.
-Effector cells (cytotoxic T Cells): A type of lymphocyte that, when activated, kills infected cells as well as certain cancer cells and transplanted cells.
-Memory cells: remember weapons forever, can quickly reactivate.
24. Describe three mechanisms of how antibodies function to combat infection (Figure 43.19).
1. Neutralization (trung hòa): Antibody bound to antigens on the surface of a virus neutralizes it by blocking its ability to bind to a host cell.
2. Opsonization: Binding of antibodies to antigens on the surface of bacteria promotes phagocytosis (thực bào) by macrophages (đại thực bào) and neutrophils (bạch cầu trung tính).
3. Activation of complement system (hệ thống bổ xung) and pore formation (hình thành lỗ chân lông): Binding of antibodies to antigens on the surface of a foreign cell activates the complement system. The membrane attack complex forms pores in the foreign cell’s membrane, allowing water and ions to rush in. the cell swells and eventually lyses (thể làm tan).
25. Explain the difference between active and passive immunity, and know an example of passive immunity.
-Active Immunity: make your own antibodies
-Passive Immunity: get them from someone else (breast feeding, vaccination).
26. Describe an allergic reaction, including the roles of IgE, mast cells, and histamine (Figure 43.22).
- Allergic reactions occur when a person's immune system reacts to normally harmless substances in the environment. Allergic reactions are distinctive because of excessive activation of certain white blood cells called mast cells and basophils by a type of antibody called Immunoglobulin E (IgE).
27. Describe the infectious (truyền nhiễm) agent that causes AIDS and explain how it damages the immune system.
-Infections of the type 2 virus, which is sexually transmitted, pose a serious threat to the babies of infected mothers and can increase transmission of HIX, the virus that causes AIDS.
-The HIV (immunodeficiency virus), both escapes and attacks the adaptive immune response. It infects helper T cells w/high efficiency. It infects some cell types that have low levels of CD4 (macrophages and brain cells)
Chapter 43 – The Immune System
1. Describe the function of the immune system.
Function: protect body from pathogens + foreign objects, destroy infected or malignant cells, and remove cellular debris.
System includes: thymus, spleen, lymph nodes and tissues, stem cells, white blood cells, antibodies.
2. Compare innate and acquired immunity, and how they differ in terms of how quickly they attack a pathogen, and how they recognize a pathogen.
Innate immunity- immediate defense upon infection and foundation for adaptive immunity
-rapid response
-distinguishes non-self from self- molecular recognition. then, receptor molecules bind specifically to molecules from foreign cells or viruses.
-recognition of traits shared …show more content…
by broad ranges of pathogens w/ small set of receptors.
Acquired immunity(adaptive)- activated when innate immune respond to the infection
-slower response
-has different receptors for each of particular part of a particular molecule in a particular pathogen.
-recognition of trails specific to particular pathogens w/ many receptors
Innate immunity defenses found in human (vertebrates) (goals 3-10):
3. Describe each barrier defense, where each is located in the body, and how each works to combat infections.
Barrier defense-
-location: skin, mucous membranes in digestive, reparatory, urinary, and reproductive tracts.
-function to combat infections: -produce mucus- for defense by trapping microbes and other particles. ex. lungs -saliva/tears/mucous secretions- provide a washing action that prevents fungi and bacteria dwelling on our skin -creates hostile environment to protect immune system- ex. lysozyme in tears/saliva kills most of the bacteria near that area
4. Explain the role of Toll-like receptors (TLRs) in combating infections, including what types of cells typically have TLRs, and what happens when pathogens bind TLRs.
Toll-like receptors (TLRs)- recognizes a molecular pattern or characteristic on certain pathogens -ex. lipopolysaccharide and flagellin are bacteria found in fungi and viruses. -TLR detects these- response factors
-then, phagocyte cells engulf them- in vacuoles
-vacuoles fuses with lysozyme to destruct these pathogens. -produce gases in lysozyme with poison -lysozyme and other enzymes inside vacuoles can degrade pathogens
5. Define phagocytosis, and explain how phagocytes combat pathogens. Name the four major types of phagocytes found in humans, where the normally reside in the body, and their role in combating pathogens.
phagocytosis- engulfing pathogens for destruction
4 major types of phagocytes in humans:
1. Neutrophils where: circulate in the blood and travel into tissues role: phagocyte
-they form pus(dead phagocytes)
2. Macrophages: "big eaters" where: migrate throughout body, others reside permanently in organs + tissues role: phagocyte - secrete cytokines- calls for help -attract Neutrophils
3. Dendritic cells: where: mainly tissues like skin, places where it contact the environment role: eat and present antigens
4. Eosinophils: where: often found beneath mucosal surfaces role: low phagocytic activity, help kill parasites, worms
6. Explain what types of cells are targeted and destroyed by natural killer cells.
-detect abnormal array of surface proteins- that has virus-infected + cancerous cells.
-if detected- they kill invaders by releasing chemicals
7. Explain how interferons combat pathogens, where they originate, and how they function to combat pathogens.
interferons- proteins that provide innate defense by interfering with viral infections -ex. virus-infected body cells produce- interferons function: let other cell know there is infection + stop the spread of the virus in the body -ex. hepatitis c
8. Describe the role of complement proteins in innate immunity, when and where they are present, where they originate, where they act, and what they combat.
complement protein- about 30 proteins in blood plasma combat: bind + lyse (burst) pathogens originate: made by liver when: they can be triggered by cytokines of infection; cascading effect
9. Describe the inflammatory response, including the four characteristics of inflammation
-characteristics: redness, heat, swelling, and pain
-inflammatory response- the changes brought about by signaling molecules released upon injury or infection
10. (rubor, tumor, calor, dolor), how inflammation is triggered, and how it affects blood vessels of the infected tissue, the effect on neutrophils. (Everything in Figure 43.8 – important!) figure 43.8
mast cells- found in connective tissue
blood vessels: vasodilatation occur- allowing more blood to flow to the damaged tissue -& increased permeability of the blood vessels
11. Know how two types of cells found in your tissues that can trigger inflammation, the chemical messengers they release, and the results of sending these chemical messengers. (Figure 43.8 – important!)
-mast cells and macrophages triggers inflammation - chemical messengers: histamine & cytokines
roles of chemical messengers:
- cause vasodilatation
- attracts Neutrophils from capillaries (which can phagocytosis cell debris & heal tissue)
12. Define antigens, epitope, and antigens receptors.
antigens- found on the surface of pathogens -usually foreign + large molecule that's either protein or polysaccharides -trigger production of antibodies when bonded with a antigen receptors
epitope (antigenic determinants)- parts of antigen; it connects to antigen receptors. -it predicts with type of antibody should be made depending on the shape -on the same antigen, it has multiple epitope ex. ONE antigen can trigger to make different antibody ie. antibody A, B, C shown above
antigen receptors- protein located on immune cells that has a specific biding site for antigen -detects antigens from pathogens -there's various types of antigen receptors
13. Describe the antigen receptors found on the surface of Bone marrow lymphocytes (also know as B cells), and the result when they bind antigen.
B cells:
-Y-shaped molecule
-has 4 polypeptide chains: 2 identical heavy chains and 2 identical light chains.
Binding:
-attaches to epitopes of antigen
-activate antibody to circulate in body fluids
-antigen receptors -> secrete antibody/immunoglobulin (they come off) -difference: secreted rather than membrane bonded
-works like a lock and key
-the antibodies can fit into antigens located on the pathogen or free antigens floating
14.
Describe the antigen receptors on the surface of T lymphocytes (also known as T cells), and the result when they bind antigen.
T cells:
-2 polypeptide chains: alpha and beta chain
- variable(v) regions- antigen-biding site
-constant (c) region- the main body of the antigen receptor
Binding:
-T-cells only bind to antigen that are presented on the surface of host cell
15. Describe the protein structure and function of an antibody/immunoglobulin, and where the variable (V) and constant (C) regions are found.
-structure: antibody/immunoglobulin formed from the antigen receptors on the B Cell -turned into soluble structure rather than membrane bonded
-function: bind to antigens on the pathogens of FREE floating antigens
- structure: variable(v) regions- amino acids are different in each B cell constant (c) region- amino acids are constant
-function: bind to host cell's MHC and antigen fragments at antigen presentation
16. Explain the function of the MHC molecules, and their role in antigen presentation.
-MHC molecule- host protein that displays the antigen fragments on the cell
surface
-pathogen infects or takes over host cell
-host cell cleave antigen into smaller peptides- makes antigen fragments
-binds antigen fragment on- MHC molecule inside the cell
-antigen presentation- display the antigen fragment in a exposed groove of the MHC protein
-T cell antigen receptor recognize and bonds- adaptive immune response
17. Explain how the particular structure of a lymphocyte’s antigen binding site forms during development using gene rearrangement.
Variable(v) region- shuffled; cut + pasted randomly this allows for millions of different variable regions for the BCR
18. Explain why the antigen receptors of lymphocytes are tested for self-reactivity during development, and what happens to cells that are self-reactive.
-In bone marrow, they make sure they don't attack self
-if it's self-reactive- kills itself by apoptosis
19. Describe the role of clonal selection (Figure 43.14) in the immune response.
clonal selection- antigen selects which lymphocyte(different versions of b or t cells) & clone through proliferation(mitosis)
- activated by antigen binding to matching antigen receptor
-once attached + activated, T cell undergoes multiple cell division (clone) -daughter cells either become Effector Cells or Memory Cells.
20. For B cells, distinguish between the function of effector cells (plasma cells) and memory cells, and when each are produced after exposure to antigen. Describe how plasma cells help combat an infection.
Effector Cells- short-lived cells- effect immediately -In B cells- plasma cells secretes antibodies from antigen receptor Memory Cells- long-lived cells- saved until later -It can respond rapidly, when exposure to same antigen in the body later in the time
21. Describe the cellular basis for immunological memory, know why vaccines work (secondary immune responses), how vaccinations work, and the example of smallpox.
immunological memory: responsible for the long-term protection that a prior infection or vaccination provides against many disease. -if you survive infection, you'll be immune to it forever
primary immune response: first exposure to a pathogen, get symptoms, feel sick. -Takes 10-17 days after the initial exposure; body makes lot of antibodies from effector cells from cloning -also stores memory cells for later secondary immune response: second exposure to the same pathogen, no symptoms, faster, more efficient response -memory cells from primary immune response- enable rapid formation of clones of thousand of effector cells
why/how vaccination works:
-inject patients w/ weakened viruses (measles, polio, flu) -from this, our body makes: memory B cells -> protect us from future exposure to the same pathogen
example smallpox:
-Edward Jenner: injected ppl w/ cowpox -from this people made memory cells against smallpox
-so in general, if you inject the body with small amount of pathogen/virus, our body will make memory cells & antibodies more quickly, which will prevent us to catch the same pathogen/virus again
22. Describe the roles of helper T cell in both humoral and cell-mediated immunity, and the role of an antigen-presenting cell in helper T cells function.
-A type of T cell that, when activated, secretes cytokines that promote the response of B cells (humoral response) and cytotoxic T cells (cell-mediated response) to antigens.
-Antigen-presenting cell: A cell that upon ingesting pathogens or internalizing pathogen proteins generates peptide fragments that are bound by class II MHC molecules and subsequently displayed on the cell surface to T cells. Macrophages, dendritic cells, and B cells are the primary antigen-presenting cells.
23. For T cells, distinguish between the function of effector cells (cytotoxic T cells) and memory cells, and when each are produced after exposure to antigen. Describe how cytotoxic T cells help combat an infection.
-Effector cells (cytotoxic T Cells): A type of lymphocyte that, when activated, kills infected cells as well as certain cancer cells and transplanted cells.
-Memory cells: remember weapons forever, can quickly reactivate.
24. Describe three mechanisms of how antibodies function to combat infection (Figure 43.19).
1. Neutralization (trung hòa): Antibody bound to antigens on the surface of a virus neutralizes it by blocking its ability to bind to a host cell.
2. Opsonization: Binding of antibodies to antigens on the surface of bacteria promotes phagocytosis (thực bào) by macrophages (đại thực bào) and neutrophils (bạch cầu trung tính).
3. Activation of complement system (hệ thống bổ xung) and pore formation (hình thành lỗ chân lông): Binding of antibodies to antigens on the surface of a foreign cell activates the complement system. The membrane attack complex forms pores in the foreign cell’s membrane, allowing water and ions to rush in. the cell swells and eventually lyses (thể làm tan).
25. Explain the difference between active and passive immunity, and know an example of passive immunity.
-Active Immunity: make your own antibodies
-Passive Immunity: get them from someone else (breast feeding, vaccination).
26. Describe an allergic reaction, including the roles of IgE, mast cells, and histamine (Figure 43.22).
- Allergic reactions occur when a person's immune system reacts to normally harmless substances in the environment. Allergic reactions are distinctive because of excessive activation of certain white blood cells called mast cells and basophils by a type of antibody called Immunoglobulin E (IgE).
27. Describe the infectious (truyền nhiễm) agent that causes AIDS and explain how it damages the immune system.
-Infections of the type 2 virus, which is sexually transmitted, pose a serious threat to the babies of infected mothers and can increase transmission of HIX, the virus that causes AIDS.
-The HIV (immunodeficiency virus), both escapes and attacks the adaptive immune response. It infects helper T cells w/high efficiency. It infects some cell types that have low levels of CD4 (macrophages and brain cells)