Easily Forgotten Pieces of Information

Question 1

What happens when a T cell becomes activated

Answer 1

Colonial Expansion

Some activated T-cells are formed

Some memory cells are formed

Question 2

What CD number is expressed by killer T cells?

Answer 2

CD8

Question 3

What CD number is expressed by helper T cells?

Answer 3

CD4

Question 4

CD 4 cells produce cytokines: what do these do?

5

Answer 4

Activate macrophages

Activate killer T cells

Cause activation of B-cells

Cause antibody class switching (IgM to other type other than D)

Activate eosinophils

Question 5

How do CD4 cells (helper T cells) activate other cells?

Answer 5

They secrete cytokines

Question 6

What are the four ways antibodies deal with antigens?

Answer 6

Precipitation/agglutination

Lysis

Neutralisation

Opsonisation

Question 7

How do antibodies being about lysis?

Answer 7

Antibodies bind to bacterium which activated complement system - forms MAC

Question 8

How do antibodies interfere with viruses?

Answer 8

They can interfere with viral entry into host cell

Question 9

How exactly do antibodies act as opsins?

3

Answer 9

Antibodies bind to pathogens

A phagocyte has antibody receptors which bind to the pathogen

Phagocyte phagocytoses the cell

Question 10

What are the two ways of classifying immunity in separate ways?

Answer 10

Natural or artificial

Active or passive

Question 11

What are the four types of immunity?

Answer 11

Natural active
Artificial active
Natural passive
Artificial passive

Question 12

What are the functions of the lymphatic system?

Answer 12

Fluid balance
Fat absorption
Defence

Question 13

What does the lymphatic system consist of?

4

Answer 13

Lymph
Lymph vessels
Lymphatic tissue
Lymphoid organs

Question 14

What makes up the lymph vessels?

Answer 14

Lymphatic capillaries
Lymph collecting vessels
Lymphatic trunks
Lymphatic ducts

Question 15

What factors promote lymph flow?

4

Answer 15

Active skeletal muscles
Active skeletal muscles

Respiratory pump - pressure changes in the thorax during breathing

Pulsations of nearby arteries

Rhythmic smooth muscle contractions in the walls of the lymphatic trunks & thoracic duct

Question 16

What are the two types of lymphoid tissue?

Answer 16

Diffuse lymphatic tissue

Lymphoid follicles

Question 17

Describe the structure of the thymus.

5

Answer 17

Flat, bi-lobed organ situated above the heart

Lobes surrounded by a capsule and divided into lobules which are separated by trabeculae (ct)

Lobule has a cortex and medulla

Cortex = densely packed with thymocytes

Medulla = sparsely populated with mature cells

Question 18

What happens in bone marrow?

Answer 18

B cell maturation

Immature B cells proliferate and differentiate here

Question 19

List the secondary lymphoid organs.

Answer 19

Lymph nodes

Spleen

Tonsils

Appendix

Question 20

Write a note on lymph node function

3

Answer 20

Filter lymph – Antigens that enter tissue spaces are trapped in lymph nodes

Reticular fibres support the resident dendritic cells, macrophages and lymphocytes

Receive lymph from afferent lymphatic vessels and drain from efferent
lymphatic vessel

Question 21

Write a note on lymph node structure.

Answer 21

Cortex

Paracortex

Medulla

Question 22

Describe a lymph node cortex.

4

Answer 22

Outermost layer

Has a subcapsular sinus

Diffuse lymphatic tissue

Lymphatic follicles - mainly B cells - primary and secondary

Question 23

Describe a lymph node paracortex.

3

Answer 23

Beneath the cortex

Populated largely by T cells

Initial T & B cell activation occurs here

Question 24

Describe a lymph node medulla.

Answer 24

Innermost layer

Medullary cords (diffuse lymphatic tissue – many plasma cells)

Question 25

List the secondary lymphoid organs.

3

Answer 25

Spleen

Tonsils

Peyer’s patches

Question 26

What are the three characteristics of the adaptive immune system?

Answer 26

Produced target-specific receptors e.g. antibodies and T-cell receptors

Memory

Improvement upon re-exposure

Question 27

What does lysozyme do exactly?

Answer 27

It attacks the cell walls of bacteria especially gram +

Question 28

What are the physical barriers of the body?

Answer 28

Skin and mucosae

Question 29

What are the physiological mechanisms of the innate immune system?
(5)

Answer 29

Body fluids which can wash away pathogens

pH

Body temperature

Commensals

Proteins such as lysozyme

Question 30

What cells are phagocytes?

5

Answer 30

Neutrophils 
Eosinophils 
Monocyte
Dendritic Cell
Macrophage

Question 31

What cells are antigen presenters?

3

Answer 31

Monocyte
Dendritic Cell
Macrophage

Question 32

List some ways the phagolysosome kills pathogens.

6

Answer 32

Acidification

Toxic oxygen-derived products e.g. hydrogen peroxide

Toxic nitrogen oxides e.g. nitric oxide

Antimicrobial peptides e.g. defensins

Enzymes -> lysosome (cell wall)

Competitors ->lactoferrin binds iron

Question 33

What two things can be used as opsins?

Answer 33

Activated complement components (innate system)

Antibodies (adaptive immune system)

Question 34

Name a pro-inflammatory molecule.

Answer 34

Prostaglandins

Question 35

How do interferons (cytokines) interfere with virus infected cells?
(4)

Answer 35

Cells activate factors that interfere with viral replication

Cells produce RNase enzymes

Cells downregulate protein translation

Cells upregulate pro-apoptotic proteins

Question 36

What can activate complement?

Answer 36

Antigen-antibody complexes

Pathogens themselves

Question 37

How does complement cause inflammation?

Answer 37

It causes swelling

Vascular permeability

Contraction of smooth muscle

Degranulation of basophils and mast cells