9. how the body responds to infection

Question 1

primary lymphoid organs

Answer 1

thymus, bone marrow (b cells differentiate- some may start here and leave early to mature in thymus)

Question 2

Answer 2

Question 3

secondary lymphoid tissues

Answer 3

spleen

lymph nodes

mucosa associated lymphoid tissue

Question 4

infectious agents

Answer 4

Viruses

Bacteria

Fungi

Protozoa

Worms

Question 5

Answer 5

Question 6

what is different about mast cells

Answer 6

they dont circulate in blood

Question 7

what are the two categories of secreted mediators of immunity

Answer 7

Question 8

innate immunity

Answer 8

• Quickly activated
• Remains the same on repeated exposure to the

same microbe

• Moderate efficiency
• General response to categories of microbes
• Recognition of ‘pathogen-associated molecular

patterns’ (PAMPs), eg. bacterial lipopolysaccharide,

viral double-stranded RNA

•Recognition by ‘pattern recognition receptors’ (PRRs)

that are widely expressed, eg. toll-like receptors

Question 9

adaptive immunity

Answer 9

• More slowly activated
• Improves on repeated exposure to the same microbe
• High efficiency
• Specific response tailored to individual microbes
• Recognition of antigens specific to each type of

microbe

•Recognition by antigen-specific receptors clonally

expressed by lymphocytes

Question 10

stages of a primary immune response

Answer 10

1. epithelial barrier
2. immediate local response: complement proteins and macrophage
3. early induced response (innate/ inflammatory): activation of mast cells and macrophages attract leucocytes and serum proteins (more complement)
4. later adaptive response: antigen carriage by dendritic cells to lymphoid tissue, activation T and B lymph, recirculation,

then memory cells following primary immune response

Question 11

Answer 11

Question 12

primary vs secondary immunodeficiency

Answer 12

primary: genetic
secondary: acquired during life (AIDS)