Unit 2- Cells & Tissues in the Immune System

Question 1

all cells of the immune system are derived from _____ _____ in the ______ _______ except T Cells which are made in the _________

Answer 1

stem cells
bone marrow
thymus

Question 2

What is Clonal expansion?

Answer 2

lymphocyte receptors with varying affinity for the antigen- the cell with the highest affinity for the most abundant antigen will have growth advantage

Question 3

What is the role of B Cells?

Answer 3

• when B cells encounter an antigen it gives rise to plasma cells (plasma cells produce antibodies)

Question 4

What is the role of T Cells?

Answer 4

recognise peptide fragments of antigen

Question 5

What two types of chains does an antibody contain?

Answer 5

two heavy chains & two light chains

Question 6

What is the top of the antibody known as? What about the bottom?

Answer 6

Top- variable region

Bottom- constant region (links the antibody to other immune defence cells)

Question 7

What are Cytokines?

Answer 7

chemical messengers secreted by the cells of the immune system

Question 8

What do Cytokines do?

Answer 8

• bind to receptors on target cells

- encourage cell growth, cell activation & direct cellular traffic

Question 9

What are Cytokines also known as? Why?

Answer 9

Interleukins

they serve as messengers between white blood cells/ leukocytes

Question 10

What are and what is the role of Natural Killer Cells?

Answer 10

Cytotoxic cells containing granules filled with potent chemicals that kill on binding

Question 11

Macrophages are called different things depending on their _______ but they’re all part of the _____-_______ _____

Answer 11

location in the body e.g. Kupffer cells (liver), monocytes (blood)

Reticulo-Endothelial System (RES)

Question 12

What are Mononuclear Phagocytes activated by?

Answer 12

T Cell Cytokines

Question 13

What do Dendritic cells do?

Where are they found?

Answer 13

initiate adaptive immune response & activate T cells

immature dendrites reside in peripheral tissue & migrate to lymph nodes as they mature

Question 14

What are Granulocytes?

Answer 14

white blood cells

Question 15

What are the three types of Granulocytes?

Briefly describe their appearance?

Answer 15

Neutrophil- darkly stained structures but light cell staining
Eosinophil- medium, staining & visible circular structures
Basophil- darkly stained

Question 16

What do Neutrophil Granulocytes do?

Answer 16

express receptors for immunoglobulin & are involved in the acute inflammatory response

Question 17

What is the role of Eosinophil Granulocytes?

Answer 17

carry receptors for IgE & are involved in the destruction of IgE coated parasites
Also respond to allergen

Question 18

What do Basophil cells do?

Answer 18

secrete chemicals responsible for immediate hypersensitivity following antigen induced aggregation

Question 19

Give examples of Primary Lymphoid Organs?

Answer 19

Bone Marrow (develop mature B cells)
Foetal liver (haemotopoesis)

Question 20

What are some Secondary lymphoid organs?

Answer 20

Spleen
Lymph Nodes
Mucosal- associated lymphoid tissue e.g. gastrointestinal, respiratory tract

Question 21

What are Lymph Nodes? Where are they found and what is their role?

Answer 21

small, bean shaped structures that are found along the lymphatic routes in the body
Contain specialised compartments where immune cells congregate and where they encounter antigens

Question 22

What is Red Pulp? Where is it found & What else does it contain?

Answer 22

Found in the Spleen
Red Pulp is a site of red blood destruction also contains White Pulp which is where lymphocytes respond to blood-borne pathogens

Question 23

What is Opsonisation?

Answer 23

the identification of an invading pathogen

Question 24

Give examples of Cells involved in Phagocytosis?

Answer 24

Macrophages
Neutrophils
Dendritic Cells

Question 25

What is the Complement Cascade?

Answer 25

the activation of one protein/ enzyme activates the next protein in the cascade.

Question 26

Which type of immunity is this:

Foreign agent is recognised by lymphocytes & acquires a memory towards it

Answer 26

Adaptive Immunity

Question 27

Upon engagement with an antigen B Cells release ______ whereas T cells release ________

Answer 27

Antibodies

Cytokines

Question 28

What are the three ways Antibodies work?

Briefly describe each mechanism.

Answer 28

1. Neutralisation- blocking the biological activity of their target molecule
2. Opsonisation- interact with receptors and allowing them to recognise and respond to the antigen (uses macrophages, neutrophils, basophils etc)
3. Complement Activation- cause direct lysis by complement recruitment