Acute Inflammation

Question 1

What are the 5 recognised signs of inflammation?

Answer 1

1. reddening - increase blood flow to the area due to dilation of the arteries
2. swelling- fluid from dilated blood vessels into the inflamed tissue
3. increased temperature
4. pain- chemical mediators are released into damaged tissue
5. loss of function

Question 2

What are some of the causes of inflammation? (4)

Answer 2

micro-organisms, trauma, immune responses e.g. hypersensitivity, malignant neoplasms

Question 3

What is acute inflammation? How are these infections generally resolved?

Answer 3

sudden onset & lasts a few hours- a few days
resolved by regeneration with hosts defence mechanisms - becomes scar tissue via fibrosis

Question 4

How can we distinguish acute and chronic inflammation by physical appearance?

Answer 4

acute- swollen, red
chronic- pale, shrunken

Question 5

What happens at the capillary bed to cause dilation?

Answer 5

capillary sphincters which prevent arteriole blood entering the capillary network fails leading to a rush of blood into the capillary network

Question 6

What are the three stages to acute inflammation?

Answer 6

1. Initial Phase
2. Exudate phase
3. Migration of Leukocytes

Question 7

What happens in the initial phase of Acute Inflammation?

Answer 7

Hyperaemia occurs - arteriole and capillary dilation via the use of chemical mediators

Question 8

What happens in the Exudate phase of Acute Inflammation?

Answer 8

increase in vascular permeability due to endothelial cell contraction (contraction is caused by histamine release by mast cells)
contraction releases exudate fluid into surrounding tissue

Question 9

What does the Leukocyte migration stage of Acute Infection do? (3)

Answer 9

margination- altered blood flow and loss of axial stream
chemotaxis attract and activate leukocytes, fibrin degradation products & cytokines
white blood cells emigrate via intracellular junctions

Question 10

What role do Neutrophils play in Inflammation? (2)

Answer 10

Fusion of phagosome with lysosomes to kill or degrade material
secretion and/or release of granules into exudate to enhance acute inflammatory response

Question 11

How are Neutrophils recruited for use in an inflammatory response? (2)

Answer 11

1. they loosely stick to walls in small veins and capillaries and roll along
2. at the junction between endothelial cells the neutrophils migrate out and travel to the site of damage

Question 12

What role do Mast Cells play in inflammation?

Answer 12

degranulate in tissue injury, releasing histamine and serotonin (which are chemical mediators of vasodilation, chemotaxis and pain)

Question 13

What is Pyrexia and what agents are responsible for it?

Answer 13

Pyrexia= fever
Pyrogens act on temperature control centres in the hypothalamus to raise body temp

Question 14

Where are Pyrogens found?

Answer 14

Gram negative organisms - in their cell walls
Damaged tissue cells- the necrosis releases pyrogens
Antigens- antibody complexes release pyrogens

Question 15

Briefly summarise the sequence of events in Acute Inflammation? (6)

Answer 15

1. Momentary Vasoconstriction
2. Dilation
3. Exudation of fluid into tissues
4. Margination of leukocytes
5. Emigration of leukocytes through endothelium
6. Increased temperature

Question 16

Name three functions of Inflammatory Exudate? (there’s 6)

Answer 16

• Dilutes the toxic agent
• The protein components may contain antibodies ( IgG) - which attack or coat (opsonise) the irritant
• Contains fibrin which immobilises the irritant
• Wash away the irritant if on a surface, e.g. skin and alimentary tract
• Bring the irritant via the lymphatic vessels to the local lymph nodes

Question 17

Snakes Can Fit Down Hose Pipes

Answer 17

Types of exudate fluid
Serous Catarrhal Fibrinous Diphtheritic Haemorrhagic Purulent

Question 18

Briefly describe Serous exudate fluid and when does this appear?

Answer 18

appears in mild vascular injury in an organ/ vessel
clear - cloudy fluid with little protein in

Question 19

Briefly describe Catarrhal exudate and where does this occur?

Answer 19

Occurs on mucous membranes with goblet cells or mucous glands
Varies from watery to gelatinous & cloudy/ pinkish in colour

Question 20

Where does Fibrinous exudate appear? What does it look like?

Answer 20

Occurs in severe cases of endothelial injury where Fibrinogen has escaped from the blood.
Appears as yellow coagulum on the surface of tissues

Question 21

What can Fibrinous exudate lead to?

Answer 21

Cysts- can coagulate to form a cyst

Question 22

When does Diphtheritic exudate fluid appear and why is it hard to remove?

Answer 22

appears in severe forms of fibrinous exudate where there is necrosis of underlying tissues
firmly adheres to tissues (removing it leads to tearing of tissues)

Question 23

In what pathology is Diphtheritic exudate found normally?

Answer 23

in fungal infections- the toxins penetrate the underlying tissues which causes coagulative necrosis

Question 24

What is the main component needed for Haemorrhagic exudate to form?

Answer 24

Haemorrhage

Question 25

Where is Haemorrhagic exudate found commonly? What happens if its widespread vs localised?

Answer 25

seen in lymph nodes, lungs and intestines in cases of severe inflammation
widespread= death
localised= bruising

Question 26

What does Purulent exudate consist of? What makes it a fluid?

Answer 26

Pus- a mixture of dead and dying neutrophils with necrotic cells and pyogenic agent
Proteolytic enzymes released by the dying neutrophils lyse tissue cells to form a fluid

Question 27

What happens to an abscess inside a cavity?

Answer 27

Macrophages digest the necrotic remains and fibrous tissue organises the interior- resulting in a fibrous scar