Topic 13: Organs of the immune system, Natural immunity; The complement system

Question 1

What should be mentioned in this topic?

Answer 1

• Organs of the immune system
• Natural immunity
• The complement system

Question 2

Organs of the immune system

Answer 2

Primary (central) and Secondary(peripheral)

Primary (central)
•Thymus
•Bursa (B-equivalents): Embryonic liver Bone marrow

Secondary(peripheral)
•Lymph nodes
•Spleen
•MALT Mucosa Associated LymphTissue 
•GALT Gut Associated LymphTissue

Question 3

Natural immunity:

Answer 3

Non-specific, less effective, immediately acting response

• Main molecular components
• Main cellular components
• Functional characteristics
• Humoral factors:

Question 4

Natural immunity:

Main molecular components

Answer 4

• Complement factors and their receptors
• Heat shock proteins
• Fc receptors
• Inflammatory cytokines, histamine,

Question 5

Natural immunity:

Main cellular components

Answer 5

• Macrophages
• Natural killer cells
• Granulocytes
• Dendritic cells

Question 6

Natural immunity:

Functional characteristics

Answer 6

• None antigen specific
• No immunological memory
• Rapid reactivity
• Linear amplification of the reaction

Question 7

Natural immunity:

Humoral factors

Answer 7

• Complement system
• Lysosin
• C-reactive protein
• Interferon – proteins released from virus-infected cell that inhibits viral replication

Question 8

The complement system:

Activation of cascade

Answer 8

The cascade is activated in three ways:

• Classic adaptive pathway
  - Known antigen-antibody complex
• Natural hereditary alternative pathway:
  - unknown antigen appears
• MBL:mannosebinding lectin
  - Binds oligosaccharides of certain virus/bacteria

Question 9

The complement system:

3 Funtions of the Complement

Answer 9

The 3 Funtions of the Complement
1. Complement has an intrinsic ability to LYSE bacterial membrane.
2. Complement initiates CHEMOTAXIS, Complement-factors attract phagocytes to the site of
the reaction.
3. Stimulate OPSONIZATION, facilitating bacterial phagocytosis (resulting in Inflammation)