Immune System

Question 1

Innate Immunity

Answer 1

Composed of defenses that are always active against infection, but lack the ability to target specific pathogens.

Question 2

Adaptive Immunity

Answer 2

Defenses that target a specific pathogen. It leads to immunological memory for quicker attack upon reinfection.

Question 3

Bone Marrow

Answer 3

Produces all leukocytes that participate in the immune system.

Question 4

Spleen

Answer 4

Location of blood storage and activation of B cells, which turn into plasma cells to produce antibodies as part of the adaptive immune system.

Question 5

Humoral Immunity

Answer 5

When the antibodies dissolve and act in the blood after leaving the bone marrow.

Question 6

Thymus

Answer 6

Site of the adaptive immune cells called T-cells.

Question 7

T-Cells

Answer 7

Main agents of cell-mediated immunity, they coordinate the immune system and kill virally infected cells

Question 8

Lymph Nodes

Answer 8

Provide a place for immune cells to communicate and mount an attack, B-cells are activated here.

Question 9

Gut-Associated Lymphoid Tissue (GALT)

Answer 9

Tonsils, adenoids, Peyer’s patches, and appendix.

Question 10

Hematopoietic Stem Cells

Answer 10

Produce granulocytes and agranulocytes.

Question 11

Lymphocytes

Answer 11

Made by agranulocytes, responsible for antibody production, immune system modulation, and targeted killing of infected cells.

Question 12

Monocytes

Answer 12

Phagocytic cells in the bloodstream, granulocytes. They become macrophages in tissues (microglia, langerhans, and osteoclasts).

Question 13

Nonspecific Immune Rsponse

Answer 13

Cells can carry these out without learning.

Question 14

Humoral Immunity Cells

Answer 14

B cells and antibodies

Question 15

Cell Mediated Immunity

Answer 15

T cell

Question 16

Noncellular Nonspecific Defenses

Answer 16

Skin: Physical barrier, contains the enzyme defensin.
Respiratory Tract: Mucous membrane with cilia that help to push up matter for expelling or swallowing.
Eye and Oral Cavity: Produce lysozyme which is secreted in tears and saliva.
Gastrointestinal Tract: Stomach secretes acid and has a lot of nonpathogenic bacteria.
Complement: Proteins in the blood that act as nonspecific defense against bacteria, it is activate via classical antigen binding pathway or an alternative.
Interferons: Proteins that prevent viral replication and dispersion, they cause nearby cells to decrease production of viral and cellular proteins.

Question 17

Macrophages

Answer 17

Type of agranulocyte that resides within the tissue. They derive from monocytes and can become a resident population within a tissue. They become activated and they phagocytize the invader through endocytosis, it digests the invader using enzymes, and it presents pieces to other cells using a protein called major histocompatibility complex (MHC). It binds to a pathogenic peptide and carries it to the cell surface, where it can be recognized by cells of the adaptive immune system. They also release cytokines to stimulate inflammation.

Question 18

MHC Molecules

Answer 18

Class 1: Displayed by all nucleated cells in the body, it can be presented on the surface of the cell. It is called the endogenous pathway because it binds antigens from inside the cell, triggers to be killed by T-cells to prevent infection.
Class 2: Displayed by antigen presenting cells like macrophages, they pick up pathogens from the environment, process them, and then present them on MHC-II. This is an exogenous pathway because the antigens originated outside the cell. Also done via dendritic cells.

Question 19

Pattern Recognition Receptors

Answer 19

They recognize the category of the invader for production of appropriate cytokines to recruit the right type of immune cells.

Question 20

Natural Killer (NK) Cells

Answer 20

A type of nonspecific lymphocyte that are able to detect the down-regulation of MHC and induce apoptosis in these virally infected cells.

Question 21

Granulocytes

Answer 21

Neutrophils: Phagocytic, follow bacteria via chemotaxis, they can detect bacteria one they have been opsonized (tagged antibody). They create pus.
Eosinophils: Involved in allergic reactions and invasive parasitic infections, they release histamine, an inflammatory mediator. Causing vasodilation.
Basophils: Involved in allergic responses, least popular leukocyte in the bloodstream under normal conditions. Mast cells have smaller granules and exist in tissues, mucosa, and epithelium.

Question 22

Humoral Immunity

Answer 22

Production of antibodies that are specific to the antigens. B-cells are lymphocytes that produce antibodies, they mature in the bone marrow and are activated in the spleen and lymph nodes.

Question 23

Immunoglobulins

Answer 23

Antibodies can carry out many different jobs in the body. They attract leukocytes to phagocytize those antigens immediately. They cause pathogens to clump together or agglutinate, making insoluble complexes than can be phagocytized. They can block the ability of a pathogen to invade tissues, neutralizing it.

Question 24

Degranulation

Answer 24

When an antigen binds to antibodies on the surface of a mast cell, exocytosis of granule contents, releasing histamine and causing an inflammatory allergic reaction.

Question 25

Structure of Antibody

Answer 25

Two identical heavy chains and two light chains. They have an antigen binding region at the Y and the variable region at the bottom.

Question 26

Hypermutation

Answer 26

Each B cell tries to find the best match for its antigen-binding region.

Question 27

Clonal Selection

Answer 27

Only B cells that bind to the antigen with high affinity will survive.

Question 28

Constant Region

Answer 28

Part of the antibody that binds to natural killer cells, macrophages, monocytes, and eosinophils have receptors.

Question 29

Naive B-Cells

Answer 29

Those that have not yet been exposed to an antigen, they wait in the lymph nodes for their particular antigen to come along.

Question 30

Primary Response

Answer 30

They will proliferate and produce either plasma cells or memory B cells. This happens 7 to 10 days.

Question 31

Secondary Response

Answer 31

If the same microbe is encountered again, the memory cells jump into action and produce the antibodies specific to that pathogen. This helps with vaccinations.

Question 32

Positive Selection

Answer 32

Maturing only cells that can respond to the presentation of antigen on MHC.

Question 33

Negative Selection

Answer 33

Causing apoptosis in cells that are self-reactive.

Question 34

Thymosin

Answer 34

Maturation of T-cells, peptide hormone secreted by thymic cells.

Question 35

Helper T Cells (CD4)

Answer 35

Coordinate the immune response by secreting chemicals known as lymphokines. They can recruit other immune cells and increasing their activity. The loss occurs in HIV infection, prevents the immune system from mounting an adequate response to infection. In AIDS, even weak pathogens can cause devastating consequences as opportunistic infections. They respond to MHCII.

Question 36

Cytotoxic T Cells (CD8)

Answer 36

Capable of directly killing virally infected cells by injecting toxic chemicals that promote apoptosis into the infected cell. They respond to antigens present on MHCI molecules. Most effective against viral infections.

Question 37

Supressor (Regulatory) T Cells

Answer 37

Express CD4 but can be differentiated form helper T cells because they also express a protein called Foxp3. They tone down the immune response once infection has been adequately contained. These cells also turn off self-reactive lymphocytes to prevent autoimmune disease: self-tolerance.

Question 38

Memory T Cells

Answer 38

They wait until the next exposure to the same antigen.

Question 39

Types of Pathogens

Answer 39

Bacteria, Viruses, Fungi, Parasites, and Prions.

Question 40

Bacterial Extracellular Pathogen Infections

Answer 40

Macrophages, MHCII presentation, cytokines attract more cells, mast cells. Travels to lymph node where it is presented to B cells, they proliferate and travel through the bloodstream to the affected tissue. Dendritic cells are also presenting the antigen to T-cells, activating a T-cell response with CD4 T cells.

Question 41

Viral Intracellular Pathogen Infections

Answer 41

Virally infected cell will begin to produce interferons, these reduce the permeability of nearby cells, reduce the rate of transcription and translation in these cells, and cause systemic symptoms. They present intracellular proteins on their surface in conjunction with MHCI in a virally infected cell. CD8 will recognize the MHCI and antigen complex as foreign and will inject toxins into the cell to promote apoptosis.

Question 42

Self-Antigens

Answer 42

Proteins and carbs present on the surface of every cell of the body. They signal to immune cells that the cell is not threatening and should not be attacked. If it fails then autoimmunity is a problem.

Question 43

Hypersensitivity Reactions

Answer 43

Allergies and autoimmunity towards non-dangerous antigens.

Question 44

Glucocorticoids

Answer 44

Potent immunosuppressive cure for autoimmune diseases.

Question 45

Active Immunity

Answer 45

Immune system is stimulated to produce antibodies against a specific pathogen. This generates antibodies via B cells upon infection. Vaccines produce artificial exposure.

Question 46

Passive Immunity

Answer 46

Transfer of antibodies to an individual. No plasma cells are transferred.

Question 47

Lymphatic Structure

Answer 47

One-way vessel that becomes larger as they move toward the center of the body, they carry lymph and join to comprise a large thoracic duct in the posterior chest, which then delivers the fluid into the left subclavian vein. Lymph nodes are small, bean-shaped structures that provide a space for cells of the immune system to be exposed to possible pathogens