How innate system reponds

Question 1

What reopnse is triggered the moment a phsical layer is penitrated

Answer 1

The inflamation response

Question 2

Name the 4 stages which occur during the inflamation reponse

Answer 2

• Chemical signals are released from resident tissue cells attracting more cells to infection site
• Resident cells release a 2nd chemical which vasodilates the tissues capillarys making them ‘leaky’
• Neutrophils enter blood from bone marrow -> Cling to capilary walls when chemicals from tissue cells are sensed ‘slow down’
• Neutrophils enter the tissue via the leaky capilarys and follow chemical signals to infection site which get stronger the closer they get

Question 3

Stages of phagocytosis

Answer 3

1. Phagocyte adhears to pathogen or debrie
2. Pseudopod forms around the pathogen
3. Becomes a phagosome in the cell which fuses with a lysosome
4. fusion = phagolysosome- degreades the contense of the phagolysosome
5. Any material which cannot be used by the cell is exocytosed

Question 4

What methods are used to kill phagocytosed pathogens

Answer 4

Low pH envrioment inside the phagolysosome

Reactive O and N intermediates - form molecules (H2O2) hospitiable

Enzymes: Proteases(break down proteins), Lipases (break down lipids), Nuclease (Breaks down nucleic acids)

Question 5

What is the complement system

Answer 5

9 Major protein + protien complexes, act in sequence to remove pathogens
They form enzymes to remove pathogens from blood and tissues.

Question 6

What is the three triggers of the complement system

Answer 6

Classical pathway- Anti-bodys bind to pathogens -> bind to complement
Alternative pathway- Pathogen binds to the complement system
Lectin pathway- Carbohydrate of microbe binds to the complement

Question 7

Name the 3 outcomes of the complement system

Answer 7

• Labeling (opsonisation)
• Destruction (lysis)
• Recruitment (chemotaxis)

Question 8

Describe the process of opsonisation

Answer 8

labeling of pathogens with either C3b receptors or antibodys which enable phagocytes to phagocytose them

Question 9

Describe the process of destruction (lysis)

Answer 9

Lysis occurs when the MAC (membrane attack complex) forms in the cell membrane mainly made of C9. Causes the contense of the pathogen to leave the cell

Question 10

Describe the process of recruitment

Answer 10

Chemotaxsis the process by which cells locate a region due to concentration grandients

Complement proteins C3a and C5a act to degranulate mast cell
- degranulation releases inflamitory mediators which attract phagocytes to area of infection