Inflammation

Question 1

What are the 4 cardinal signs of inflammation?

Answer 1

1. Heat
2. Redness
3. Oedema
4. Pain (caused by oedema placing pressure on local nociceptors)

Question 2

Which 4 cell types are involved in an acute inflammatory response?

Answer 2

1. Platelets - aggregate, release inflammatory substances
2. Neutrophils - phagocytic WBCs
3. Basophils - in bloodstream, pro-inflammatory
4. Mast cells - in loose CT, pro-inflammatory

Question 3

Which 4 cell types are involved in chronic inflammation?

Answer 3

1. Macrophages - phagocytic WBCs, replace neutrophils
2. T lymphocytes: ‘read’ antigens and activate B lymphocytes
3. B lymphocytes: attack specific antigens
4. Fibroblasts: produce collagen to replace dead tissue cells (fibrosis)

Question 4

What are the processes involved in acute inflammation?

Answer 4

1. Vasodilation - increases blood flow to tissues
2. Increased vascular permeability - allows fluid to diffuse from blood vessels into tissue easily for delivery of WBCs and inflammatory proteins; increased interstitial fluid also allows for enhanced lymphatic drainage of pathogens and damaged tissue
3. Cellular - migration of neutrophils (phagocytic WBCs) to injured area caused by inflammatory mediators in bloodstream

Question 5

What occurs in chronic inflammation that does not occur in acute inflammation?

Answer 5

1. Macrophages replace neutrophils as the phagocytic WBC
2. Infiltration of T and B lymphocytes for specific antigen defence
3. Healing and inflammation occur concurrently (fibroblasts arrive and fibrosis occurs as new collagen is laid down)
4. Proliferation of small blood vessels as re-vascularization of injured area occurs

Question 6

What is fibrosis?

Answer 6

The laying down of new collagen fibres to replace injured or damaged tissue (type III collagen and initially disorganized, replaced by type I collagen and remodelled in later stages of healing)

Question 7

Where does inflammation fit in the stages of healing?

Answer 7

The second stage - typically Day 1 for days, weeks or months (longer in chronic inflammation or pathologies requiring longer healing) with peak inflammation Day 1-3

1. Haemostasis (4-6 hours)
2. Inflammation (Day 1 - days, weeks or months)
3. Proliferation (Day 5-7 - up to 4 weeks)
4. Remodelling (Week 4 - months or years)

Question 8

What is a granuloma?

Answer 8

A protective structure formed around an antigen or foreign substance if it cannot be healed by the body’s immune / inflammatory response.

A granuloma is made up of layers of immune and plasma cells around the antigen / foreign body, then surrounded by layers of collagen laid down by fibroblasts.