102 Inflammation

Question 1

What are mast cells & what is their role?

Answer 1

Resident cells which are involved in wound healing, defence, allergy & anaphylaxis. Contain granules of histamine and heparin

Question 2

What is the role of dendritic cells and where are they found?

Answer 2

Initiate innate immune response - found in lymphoid tissue and in the blood stream. Capture and process antigens

Question 3

What are macrophages and what is their role?

Answer 3

Antigen presenting cells which also phagocytose >1 pathogen at a time. Lyphokines stimulate.

Question 4

What are NKCs?

Answer 4

Cells which kill tumour cells - antigen not needed here

Question 5

Name the 3 granulocytes - what are their roles?

Answer 5

• Basophils contain granules of heparin and histamine. Degranulation of these in allergic response. Release IgE too
• Eosinophils - antihistamine role –> release histaminases. Kills nematodes
• Neutrophils –> diapedisis to site of inflammation/infection + phagocytosis of 1 or 2 pathogens at a time

Question 6

Describe the classical pathway of the complement system

Answer 6

• Antibodies bind to antigens on a microbe, C1 then binds to AB and is activated to cleave C4 –> C4a and C4b.
• C4 b binds to surface receptor on microbe and C4a degranulates elsewhere.
• C1 then cleaves C2 into C2a and C2b (this binds to C4b to produce C3 convertase enzyme which cleaves C3 into a and b parts).
• C3b = opsinisation on microbe - immune system attacks

Question 7

What are cytokines and what do they do?

Answer 7

Cellular signalling proteins which bind to receptors intra/extracellularly to initiate a signalling cascade e.g. to initiate transcription in the nucleus of a cell. Also inflammatory mediators

Question 8

Name the gross parts of the spleen and explain their general function

Answer 8

Red pulp = removes/destroys damaged RBCs. White pulp = acts like lymph node –> macrophages here for phagocytosis of pathogens. Present antigens to T-helper cells which produce cytokine. B cell amplification to generate ABs against the pathogens

Question 9

What is MAC and what is its role in immune response

Answer 9

Membrane attack complex - forms a transmembrane channel in the cell wall of a pathogen and causes influx of fluid = cell lysis and death

Question 10

What can mitochondrial damage lead to?

Answer 10

ATP depletion –> cell death

Question 11

What are the mediators of the vascular changes which happen in inflammation? What happens to the speed of the blood flow here - why?

Answer 11

• Histamine and NO cause vasodilation to increase the blood flow to the site of inflammation.
• Histamine and cytokines increase the permeability of the vessels (high protein exudate –> swelling)
• Blood flow slows to allow transmigration of the leukocytes

Question 12

What are the 5 steps of leukocyte traveling to the site of inflammation?

Answer 12

1. migration
2. rolling
3. adhesion
4. transmigration
5. migration towards chemotactic signal

Question 13

What affect do chemokines released from macrophages have on leukocytes during inflammation?

Answer 13

Chemokines activate the integrins on the leukocytes which make them ‘sticky’

Question 14

What are the systemic consequences of acute inflammation? (6 listed)

Answer 14

1. fever
2. anorexia
3. malaise
4. somnolence
5. tachycardia
6. hypotension

Question 15

Name 3 causes of chronic inflammation

Answer 15

1. persistent infection
2. prolonged exposure to toxic agent
3. autoimmunity

Question 16

What are granulomas?

Answer 16

Collection of epithelial histocytes - specialised macrophages in a collection. Can have a necrotic core - dead cells and pathogens