BIOL 273 - Unit 6.1 +6.2

Question 1

What are key features of the immune system

Answer 1

• Lymphoid tissues and immune cells
• Chemicals that coordinate and execute function

Question 2

What are the three major functions of the immune system

Answer 2

1. Protecting the body
2. Remvoes dead/damaged tissue and cells
3. Tries to recognize and remove abnormal cells

Question 3

Pathologies when the immune system does not perform normally

Answer 3

Incorrect response (autoimmunity)
Overreactive response (allergies)
Lack of response (Immunodeficiency)

Question 4

What are pathogens and the types of pathogens

Answer 4

disease causing agents
- Bacteria 🧫
- Viruses 🦠

Question 5

Bacteria 🧫

Answer 5

• Can be intracellular or extracellular
• surrounded by a cell membrane and cell wall
• survive and reproduce outside host
• most can be killed by drugs (antibiotics)

Question 6

Viruses 🦠

Answer 6

• Intracellular pathogens
• not cells - cannot produce alone
• some have envelope derived from host cell membrane
• cannot be killed by antibiotics (instead antiviral drugs)
• new viral particles can either rupture host cell or bud off from host cell

Question 7

Immune system organs are called what and why

Answer 7

lymphoid organs because they have lymphocytes (subset of leukocytes)

lymphoid organs are connected by blood vessels and the lymph vessels

Question 8

Lymph

Answer 8

conduit for immunologically active cells to travel through

Question 9

Regions of the body outside lymphoid organs

Answer 9

periphery

Question 10

Primary lymphoid organs

Answer 10

Organs where lymphocytes develop
- Bone marrow - B lymphocytes mature
- Thymus - T lymphocytes mature

Question 11

Secondary lymphoid organs

Answer 11

Organs where lymphocytes interact and initiate responses
Spleen, lymph nodes, tonsils and Gut Associated Lymphoid tissue (GALT)

Filters blood and lymph for pathogens and pathogen containing lymphocytes

Question 12

Describe the two structures of the secondary lymphoid organs

Answer 12

Afferent lymph vessel: brings in lymphocytes from periphery (towards secondary lymphatic organ)

Efferent lymph vessel: allows them to keep circulating (exiting secondary lymphatic organ)

Question 13

What is it called when there is a fibrous connective wall on secondary lymphoid organs

Answer 13

Encapsulated (fibrous wall) ex. Spleen and lymph nodes

Diffuse (no wall) ex. Tonsils and GALT

Question 14

What are the six main types of leukocytes cells

Answer 14

1. Eosinophils
2. Basophils (Mast cells)
3. Neutrophils
4. Monocytes (Macrophages)
5. Lymphocytes
6. Dendritic cells

Question 15

What are Granulocytes (leukocytes)

Answer 15

cells that have prominent cytoplasmic granules

Eosinophils, basophils, neutrophils

Question 16

What are phagocytes (leukocytes)

Answer 16

can engulf and ingest pathogens

Neutrophils, macrophages, dendritic cells

Lysosomal enzymes digest pathogen

Question 17

What are cytotoxic cells (leukocytes)

Answer 17

(killer T-cells)
kill other cells, even self-cells

Eosinophils and some lymphocytes

ex. Tc lymphocytes, natural killer cells

Question 18

What are antigen presenting cells (APC’s) (leukocytes)

Answer 18

Display fragments or pathogens on cell surface

Some lymphocytes, dendritic cells and macrophages

Question 19

Antigens (Ag)

Answer 19

antibody generator - substances that are recognized by an antibody and induces an immune response

Question 20

Antibodies (ab)

Answer 20

proteins that bind specifically to Ag’s and target pathogens for destruction

Question 21

Eosinophils (primary role and where is it found)

Answer 21

cytotoxic granulocytes with bright pink staining granules

Role in defence against parasites and function in allergic response (degranulate)

Found in digestive tract lungs, genital tract, and skin

Question 22

How do eosinophils respond to antigens and during allergic responses

Answer 22

respond by binding to an antibody-coated parasite and degranulate - spew granule contents

Granule contents ; damage and kill parasites - cytotoxic

Also degranulate in allergic responses

Question 23

basophils

Answer 23

granulocytes involved in allergic responses

have large dark blue staining granules (granulocyte)

Basophils in blood (rare in numbers), mast cells in tissue - found in digestive tract, lungs and skin

Granules contain histamine. heparin, cytokines

Question 24

How do basophils respond to allergic responses

Answer 24

degranulate

Question 25

Neutrophils

Answer 25

granulocytes that are phagocytic Most abundant leaves circulatory system to attack pathogens in tissues Granules contain cytokines that cause fever and start other inflammatory responses

Question 26

Monocytes

Answer 26

precurser cells of tissue macrophages move into tissues to become macrophages function as scavengers and phagocytose bacteria Have a role in adaptive immune response - phagocytosed pathogens are digested, and fragments are placed on the cell surface (APCs)

Question 27

Lymphocytes

Answer 27

key player in adaptive immune response dont last long in circulation and mostly found in lymphoid tissues

Question 28

Dendritic cells

Answer 28

phagocytic antigen presenting cells (APCs) (like macrophages) have long thin process found in skin and organs recognize and engulf pathogens (pathogens are digested and placed on cell surface) Activated cells than migrate to secondary lymphoid organs to present the antigens to lymphocytes

Question 29

Describe the steps to the development of red blood

Answer 29

produced in bone marrow derived from pluripotent haematopoietic stem cells give rise to uncommitted stem cells give rise to progenitor cells (that develop in each cell type)

Question 30

B lymphocytes

Answer 30

produced in the bone marrow Produces antibodies - which can be found on the cell surface as receptors (which can then interact with antigens)

Question 31

Why are B lymphocytes called B lymphocytes

Answer 31

leaves the bone marrow to mature in the Bursa of fabricius

Question 32

T lymphocytes

Answer 32

produced in bone marrow but migrates to the thymus to mature Use contact dependent signalling via T-cell receptor on T cell membrane via MHC antigen complexes CANNOT bind to free antigens

Question 33

Why are T lymphocytes called T lymphocytes

Answer 33

because they mature in the thymus

Question 34

MHC

Answer 34

Major Histocompatibility complex - proteins expressed on surface cells that display "self antigens" and "non self antigens" to T cells

Question 35

Two classes of MHC that interact with T cells and where are they located

Answer 35

Class I - on all nucleated cells Class II - on APCs

Question 36

T cell subtype: Cytotoxic T cells / killer T cells

Answer 36

Recognizes Antigen presented on Class I MHC Kills cell that expresses appropriate antigen

Question 37

T cell subtype: Helper T cells

Answer 37

Recognize antigen presented on Class II MHC Promote differentiation of B cels and T cells and can activate macrophages

Question 38

T cell subtype: Regulatory T cells (Tregs)

Answer 38

recognize antigen presented on Class II MHC Suppress other immune cells to prevent excessive immune responses