Exam 3: Study Guide 16/17

Question 1

Differentiate between non-specific (innate) and specific (adaptive) mechanisms of defense.

Answer 1

o Non-specific:
 Works the same regardless of the microorganism
o Specific:
 Born with the cells not the mechanism because the body needs to build a custom plan of attack

Question 2

List the non-specific mechanisms of defense discussed in class and give example of each.

Answer 2

o Mechanical barriers: skin, nose hairs, mucus, cilia, flushing
o Chemical Factors: Sweat, sebum, enzymes (tears and saliva), gastric juices, defensins and interferon

Question 3

List the components of vertebrate blood and describe the function of each component.

Answer 3

o Components:
 Plasma:
* Plasma proteins (albumins, globulins, fibrinogen
* Serum
 Cell Components:
* Erythrocytes, platelets, leukocytes

Question 4

Define leukocytosis, leukopenia, edema and erythema.

Answer 4

o Leukocytosis: increase in number of White Blood Cells; associated with bacterial infections
o Leukopenia: decrease in number of White Blood Cells; associated with viral infections
o Edema: Swelling
o Erythema: Redness

Question 5

Differentiate between a cell blood count and a cell blood count with differential

Answer 5

o Cell Blood Count: Counts all the blood’s cells and tells the number of RBC, WBC, and Platelets.
o Cell Blood Count with Differential: Counts all the blood’s cells and differentiates between the WBC kinds

Question 6

Explain the characteristics and the functions of the inflammatory response.

Answer 6

o Characteristics:
 Edema (swelling), Erythema (redness), Heat and Pain
o Functions:
 To destroy and remove the injurious agent
 If this not possible then it limits the effects on the body by confining or walling off the agent and its byproducts
 To repair/replace damaged tissue

Question 7

Describe the stages of inflammation.

Answer 7

o Stages:
 Chemotaxis: Tissue macrophages initiate phagocytosis and secrete cytokines
 Vasodilation: capillary walls dilate, causing edema, heat, redness and pain. More phagocytes come to the site of injury
 Phagocyte migration: margination and diapedesis
 Fibrin wall: forms around injury preventing the spread of pathogens
 Repair: cannot be finished until the injurious agent and its products are completely removed. Tissue’s ability to regenerate depends on the damaged tissue

Question 8

Define phagocytosis and describe the four phases of this mechanism.

Answer 8

o Phagocytosis is the capture and digestion of foreign particles
o Stages:
 Chemotaxis: Cytokines attract macrophages and neutrophils to infected tissues (sounds alarm to eat before an infection breaks out)
 Adherence: Attachment of microbe to phagocyte surface
 Ingestion: Via endocytositic vesicle called phagosome
 Digestion: phagosome pinches off the cell membrane and fuses with the lysosome

Question 9

Explain what neutrophil extracellular traps are.

Answer 9

o Neutrophils that transform into extracellular fibers (NETS)
o They are in places with a lot of microorganisms
o They burst to release a net that traps the microorganisms confining them so the macrophages and neutrophiles can move in and eat them.

Question 10

Describe the action of natural killer cells and of interferon.

Answer 10

o Natural Killers destroy virus-infected and abnormal cells

Question 11

Differentiate and describe the classical and alternate complement pathways.

Answer 11

o Classical Complement Pathways: Specific; The antibody-microbe complexes
o Alternate Complement Pathways: Nonspecific; Proteins that active C3 convertase

Question 12

List the organs and cells that compose the immune system.

Answer 12

o Spleen
o Thymus Gland
o Bone marrow
o Lymph nodes
o Lymphoid tissues
o Lymph ducts and vessels

Question 13

Define antigen, antigenic epitope and antibody.

Answer 13

o Antigen: A substance that provokes an immune response in the body, typically a part of a microbe or pathogen, which the immune system recognizes as foreign
o Antigenic Epitope: Also known as an antigenic determinant, this is the specific part of an antigen that is recognized by the immune system, particularly by antibodies, B cells, or T cells.
o Antibody: A protein produced by B cells in response to an antigen. Antibodies recognize and bind to specific epitopes on antigens to neutralize or destroy pathogens

Question 14

Describe the origins and subpopulations of T and B lymphocytes and their functions.

Answer 14

o Origins:
 B Lymphocytes: B cells originate and mature in the bone marrow. After maturation, they move to the lymphatic system, where they circulate and encounter antigens.
 T Lymphocytes: T cells also originate in the bone marrow but mature in the thymus. Once matured, they also circulate through the lymphatic system and blood, prepared to recognize antigens presented by infected or abnormal cells.
o Subpopulations:
 B Cells: Plasma cells and memory B cells
 T Cells: Memory T cells, suppressor, helper T cells

Question 15

Explain the role of the Major Histocompatibility Complex

Answer 15

o The role of MHC is to act as a bar code
o It displays on the cells surfaces and the recognition molecule goes through and says this is my code and then when it isn’t there code, they call everyone to come and kill it
o This prevents out immune system from attacking itself

Question 16

Differentiate between cell-mediated (cytotoxic) immunity and antibody-mediated (humoral) immunity

Answer 16

o Cell-mediated:
 Controlled by T cells and in directed against cells of the body that have been infected by agents such as viruses
o Antibody-Mediated:
 Regulated B cells and antibody production to defend the body against invading viruses and bacteria agents

Question 17

List the different types of B and T lymphocytes and describe their roles.

Answer 17

o Naïve T cells turn to effector t cell
o Helper T cells
o Cytotoxic T cells
o Memory cells

Question 18

Describe the structure of an antibody.

Answer 18

o Protein that consist of four polypeptide chains
 2 light chains
 2 heavy chains
o Heavy chain types: G, M, A, D
o Light chain types: kappa and lambda
o Have 2 antigen binding sites
Have constant domains and variable domain

Question 19

List the different classes of antibodies (immunoglobulins).

Answer 19

o IgM-first but short-lived immunoglobulin to appear in circulation after B cell stimulation. Normally appears as a complex of five immunoglobulin molecules (pentamer)
o IgG-major circulating antibody. Crosses placenta providing immunity to fetus and newborn
o IgA- provides resistance in the respiratory and gastrointestinal tracts. Passed to the newborn in mother’s first milk (colostrum)
o IgD- surface receptor on B lymphocytes activating them
o IgE- play a role in allergic reactions

Question 20

Describe the mechanism for cell-mediated (cytotoxic) immunity

Answer 20

o Then the cell mediated immune response is activated to eliminate “non-self” cells.
 T cells control and regulate these activities

Question 21

Describe the mechanism for antibody-mediated (humoral) immunity.

Answer 21

o The humoral immune response involves:
 activation of B cells.
 production of antibodies against the identified antigen

Question 22

Define antigen-presenting cell, clonal selection, clonal expansion, memory, cytokines, and lymphokines.

Answer 22

o Antigen-presenting cell: immune cells that help the body fight off infections by displaying antigens
o Clonal selection: process of producing B and T cells
o Clonal expansion: process where a single cell rapidly divides to create a large number of genetically identical cells
o Memory: a partially activated cell that knows viruses so when they come back the can kill them quicker
o Cytokines: protein to help control inflammation in the body
o Lymphokines: protein mediator produced by lymphocytes

Question 23

Describe the different ways in which antibodies can function.

Answer 23

o By binding to specific antigens on pathogens and then neutralizing the harmful effects by not allowing them to enter the cell

Question 24

Describe the primary and secondary immune response.

Answer 24

o Primary: response that occurs the first time the body encounters a pathogen
o Secondary: antibody response is more powerful and sustained (occurs with a subsequent infection by the same pathogen

Question 25

Explain how the different types of vaccines work.

Answer 25

o Trigger an immune response to defend against harmful substances

Question 26

Describe the four types of acquired immunity.

Answer 26

o Naturally acquired active immunity arises from an exposure to antigens and often follows a disease
o Artificially acquired active immunity results from a vaccination
o Naturally acquired passive immunity stems from the passage of IgG across the placenta from the maternal to the fetal circulation
o Artificially acquired passive immunity is induced by an injection of antibodies (antitoxins) taken from the circulation of an animal or another person