Session 2

Question 1

Suggest some causes of acute inflammation

Answer 1

Microbial infections, hypersensitivity reactions (acute phase), physical agents, chemicals, tissue necrosis

Question 2

What are the 4 clinical features of acute inflammation?

Answer 2

Rubor (redness), Tumor (swelling), Calor (heat), and Dolor (pain and loss of function)

Question 3

What are the 3 key changes in acutely inflamed tissues?

Answer 3

Changes in blood flow, exudation of fluid into tissues, infiltration of inflammatory cells

Question 4

How does the blood flow changes in acute inflammation?

Answer 4

Transient vasoconstriction (few seconds) and then vasodilation of arterioles and capillaries, resulting in increased blood flow (heat and redness)

Question 5

How does the permeability of the blood vessels change in acute inflammation?

Answer 5

Increase in permeability causes exudation of protein rich fluid into tissues and the slowing of circulation (swelling)

Question 6

What is stasis?

Answer 6

Stagnation or cessation of blood flow

Question 7

What changes in hydrostatic pressure and intersitium colloid osmotic pressure will cause fluid to flow out of vessels

Answer 7

Increase in hydrostatic pressure and increase in colloid pressure of interstitium cause an increase in fluid flow out of the vessel

Question 8

How is hydrostatic pressure increased in acute inflammation?

Answer 8

Arteriolar dilation

Question 9

Why does interstitial colloid pressure increase in acute inflammation?

Answer 9

Increased permeability of vessel walls leads to loss of fluid into the interstitium

Question 10

What is the clinical term for an excess of fluid in the interstitium?

Answer 10

Oedema

Question 11

What is the difference between transudate and exudate fluid loss?

Answer 11

Exudate: high protein content fluid (seen in inflammation)
Transudate: fluid loss due to hydrostatic pressure imbalance inly (low protein content)

Question 12

Which cells is histamine released from in the immediate response to cause acute inflammation?

Answer 12

Mast cells, basophils, and platelets

Question 13

Why is histamine released?

Answer 13

In response to many factors, such as physical damage, immunological reactions, complement proteins (C3a, C5a), interleukins, factors from neutrophils and platelets

Question 14

What does histamine cause?

Answer 14

Vascular dilation, a transient increase in vascular permeability and pain

Question 15

How does histamine and leukotrienes cause vascular leakage?

Answer 15

Stimulate endothelial contraction, which forms gaps in the endothelium

Question 16

How do IL-1 and TNF cause vascular leakage?

Answer 16

Stimulate cytoskeletal reorganisation that creates gaps in the endothelium

Question 17

How does VEGF cause vascular leakage?

Answer 17

It increases transcytosis (the channels across the endothelial cytoplasm)

Question 18

Name the two prominent kinins. What is there general effect?

Answer 18

Bradykinin and kallidin; increase vascular permeability

Question 19

Name two complement proteins important in the release of histamine from mast cells and which act as chemoattractants for white blood cells. Which WBC in particular do they attract?

Answer 19

C3a, and C5a; neutrophils

Question 20

Name some general actions of prostaglandins

Answer 20

The constriction or dilation of vascular smooth muscle cells, the aggregation/disaggregation of platelets, and the control of cell growth

Question 21

What is the action of chemokines?

Answer 21

Induce chemotaxis, important in recruiting inflammatory cells to the site of infection

Question 22

What are interleukins predominantly synthesised by? What is their action?

Answer 22

CD4 T lymphocytes; they promote the development and differentiation of T, B and haematopoietic cells

Question 23

What are interferons?

Answer 23

Proteins made and released by host cells in response to the presence of pathogens such as viruses, bacteria, parasites or tumour cells; they trigger an immune response

Question 24

What is TNF?

Answer 24

Tumour necrosis factor-alpha is a cytokine involved in systemic inflammation, produced mainly by macrophages

Question 25

What are the actions of TNF?

Answer 25

Primary role of TNF is in the regulation of immune cells; TNF is able to induce fever, apoptotic cell death, inflammation and other effects in order to inhibit tumorigenesis and viral replication

Question 26

What are leukotrienes?

Answer 26

Family of inflammatory mediators produced in leukocytes by the oxidation of arachidonic acid; they use lipid signalling in order to regulate an immune response, and can cause smooth muscle contraction

Question 27

Which 2 mediators are the most important in increasing blood flow?

Answer 27

Histamine and prostaglandins

Question 28

Which 2 mediators are the most important in increasing vascular permability?

Answer 28

Histamine and leukotrienes

Question 29

Which 3 mediators are the most important in causing neutrophil chemotaxis?

Answer 29

C5a, LTB4, bacterial peptides

Question 30

Which mediator is the most important in stimulating phagocytosis?

Answer 30

C3b

Question 31

Which is the most important cell of acute inflammation?

Answer 31

Neutrophils (polymorphonuclear leukocyte)

Question 32

How do neutrophils infiltrate the interstitium? (in four words)

Answer 32

Margination, rolling, adhesion, emigration

Question 33

How do neutrophils to the site of action?

Answer 33

Via chemotaxis, using chemoattractants

Question 34

What is the chief action of neutrophils? What is it facilitated by?

Answer 34

Phagocytosis; opsonins (Fc and C3b)

Question 35

Describe the O2 dependent killing mechanisms of neutrophils

Answer 35

Produces superoxide and hydrogen peroxide, and HOCl-, which cause damage to the antigen

Question 36

Describe the O2 independent killing mechanisms of neutrophils

Answer 36

Involve lysozymes and hydrolases, bacterial permeability increasing protein and cationic proteins (defensins)

Question 37

What are the three main functions of exudate in acute inflammation?

Answer 37

Delivers plasma proteins to area of injury, dilutes toxins, increases lymphatic drainage

Question 38

What is the general function of the infiltrate of inflammatory cells in acute inflammation?

Answer 38

Removes pathogenic organisms and necrotic debris

Question 39

What are the general functions of vasodilation in acute inflammation?

Answer 39

Increases delivery, increases temperature

Question 40

What are the general functions of pain and loss of function in acute inflammation?

Answer 40

Enforces rest, reduces chance of further traumatic damage

Question 41

What are the systemic effects of acute inflammation?

Answer 41

Fever, leucocytosis, acute phase response, shock

Question 42

What is fever produced by in acute inflammation?

Question 43

What is leucocytosis? Which mediators produce an accelerated release from the marrow?

Answer 43

White blood cell count above normal range for blood; IL1 and TNF

Question 44

What is the acute phase response?

Answer 44

Decreased appetite, raised pulse, altered sleep patterns and changes in plasma concentrations of acute phase proteins

Question 45

What are the potential outcomes of acute inflammation?

Answer 45

Complete resolution, chronic inflammation, death

Question 46

What are possible mechanisms of resolution?

Answer 46

Mediators have short half-lives, they may be inhibited or inactivated by degradation. They may be diluted in the exudate.

Question 47

Why is the fluid of a skin blister clear?

Answer 47

There are relatively few inflammatory cells, unless bacterial infection develops

Question 48

What occurs to cause a skin blister?

Answer 48

Collection of fluid between epidermis and lower layers; the fluid forms a cushion for the tissue underneath, allowing it to resist further damage and undergo repair

Question 49

What causes an abscess?

Answer 49

Inflammatory exudate forces tissues apart, with liquefactive necrosis in the centre