Components Of The Immune System

Question 1

What is the most fundamental function of the immune system?

Answer 1

Ability to recognize self and nonself
Must be nonreactive to self

Question 2

What are the two types of immunity?

Answer 2

Innate and acquired

Question 3

What are the characteristics of the innate immune system?

Answer 3

• Nonspecific
• Elements we’re born with
• Available on short notice
• Physical and chemical

Question 4

What are the characteristics of the acquired immune system?

Answer 4

• Specialized
• Acquired after contact with a particular agent
• Immunization happens with first contact
• Creates immunity to attacks from the same agent in the future

Question 5

What is immunization?

Answer 5

• Part of gaining acquired immunity
• Contact with an agent triggers lymphocyte activation and antibody production

Question 6

What cell lineage are adaptive immune cells derived from?

Answer 6

Mainly lymphoid, but some cells from the myeloid lineage have a role in adaptive immunity

Question 7

What cells are derived from the myeloid lineage? (6)

Answer 7

• Macrophages
• Dendritic cells
• Neutrophils
• Eosinophils
• Basophils
• Mast cells

Question 8

What do macrophages do?

Answer 8

• Phagocytosis and activation of batericidal mechanisms
• Antigen presentation

Question 9

Where are macrophages found?

Answer 9

Mainly in tissues

Question 10

What are macrophages derived from?

Answer 10

Myeloid lineage, blood monocytes

Question 11

What do dendritic cells do?

Answer 11

• Antigen uptake in peripheral sites
• Antigen presentation in lymph nodes

Question 12

Where are dendritic cells found?

Answer 12

Lymphoid organs

Question 13

What are dendritic cells derived from?

Answer 13

Myeloid lineage, monocytes

Question 14

What do macrophages and dendritic cells have in common?

Answer 14

• Antigen presentation
• Innate immune response
• Phagocytosis

Question 15

What is the function of neutrophils?

Answer 15

• Phagocytosis
• Activation of bactericidal mechanisms

Question 16

What is the function of eosinophils?

Answer 16

Killing antibody-coated parasites

Question 17

Name the granulocyte cells

Answer 17

• Neutrophils
• Eosinophils
• Basophils

Question 18

Why are granulocytes referred to as polymorphonuclear cells?

Answer 18

Have an oddly shaped nucleus with one or more lobes

Question 19

What is the function of mast cells?

Answer 19

Release of granules with histamine and other active agents

Question 20

What do basophils and mast cells have in common?

Answer 20

• Found in tissues
• Respond to parasites
• Release mediators that make endothelium more permeable —> neutrophils reaching tissue from circulation

Question 21

Where do B-cells mature?

Answer 21

In the bone marrow

Question 22

What do B-cells do?

Answer 22

• Have antigen-specific Ig receptors
• Activated B-cells differentiate into plasma cells
• Plasma cells make antibodies specific to antigen
• Adaptive immunity

Question 23

Where do T-cells mature?

Answer 23

In the thymus

Question 24

What is the receptor on T-cells called?

Answer 24

T-cell receptor (TCR)

Question 25

What are the main types of T-cells?

Answer 25

- CD4 helper T-cells - CD8 cytotoxic/killer T-cells

Question 26

What do CD4 T-cells do?

Answer 26

- Recognise antigens presented to them by APCs - Activate other immune cells (CD8, B cells, macrophages) - Specialize into subsets to coordinate immune response - Memory formation for future immune response

Question 27

Where do natural killer cells mature?

Answer 27

In the bone marrow

Question 28

What do natural killer cells do?

Answer 28

- Innate immune response - Kill cancer and virus infected cells - Have some function in adaptive immunity

Question 29

Why is the thymus important?

Answer 29

- T-cell maturation site - Removes self-reactive T-cells

Question 30

Where are plasma cells found?

Answer 30

- Lymph nodes They are B-cells that have been triggered by an antigen

Question 31

What can finding plasma cells in the blood be indicative of?

Answer 31

Cancer - myeloma

Question 32

What are the 3 antigen presenting cells?

Answer 32

- Dendritic cells - Macrophages - B-lymphocytes

Question 33

What do antigen presenting cells do?

Answer 33

- “Chew up and spit out” - Digest antigen and present peptides via MHC class II molecules to CD4 cells - Link between innate and adaptive immune system

Question 34

Why do lymph nodes swell with infection?

Answer 34

Response to infection 1) Proliferation of immune cells 2) Inflammatory response to immune system signals 3) Accumulation of pathogen and immune cell debris 4) Localized infection of lymph node

Question 35

How do immune cells find pathogens to respond to them?

Answer 35

Lymphocyte recirculation - Lymphocytes enter the lymphatic system and adhere inside lymph nodes - Lymph from infection site reaches nearest lymph node (draining lymph node) - Immune response ensues