Acute Inflammation

Question 1

Acute inflammatory response cardinal signs

Answer 1

Redness- increased blood flow, instigated by arteriolar dilation
Swelling- increased permeability of blood vessels. Vessels invariably affected are venues and sometimes capillaries but arterioles can also leak of damage is severe enough.
Heat- increased blood flow
Pain- damage to nerve pain fibres and release of chemical mediators that induce pain. Include bradykinin (from plasma), serotonin and certain prostaglandins (both from cells). Also from increased tissue tension.
Loss of function- due to death of cells and or swelling which restricts movement.

Question 2

Leukocytes involved

Answer 2

Polymorphs

• neutrophils- first leukocyte at the scene and only last a few days. Neutral staining granules.
• eosinophils
• basophils

Macrophages
Second type of leukocyte to infiltrate tissue in AIR. Can survive in tissue for extended periods of time. Main purpose is phagocytosis

Question 3

Other important cells in inflammation

Answer 3

Mast cells- derived from bone marrow, found in connective tissue. Synthesise and secrete many mediators that are involved. Histamine most commonly, causing arteriolar dilation and increases permeability of venules and capillaries in acute inflammation. Also produces heparin, serotonin and prostaglandins.
Mast cell degranulation occurs in tissue trauma as well as in allergic reactions.

Platelets- contain and release many substances, particularly serotonin which can induce vasoconstriction and pain.

Injured and dying native cells-
Epithelial
Fibroblasts- most abundant connective tissue, form collagen, elastic and ground substance
Endothelial cells- line blood vessels

Question 4

Exudate

Answer 4

Fluid that accumulates in the extra cellular fluid. Process of forming this is called exudation. Comprised of plasma, various levels of plasma proteins and leukocytes.
Degrees of tissue damage will cause 3 manifestations of vascular permeability resulting in distinct types of exudates.

Question 5

Immediate transient permeability

Answer 5

Increase immediately but short lived.
Mild injuries, results in small gaps between endothelial cells in venules. Gaps due to endothelial cell contraction and largely elicited by histamine from mast cells. This allows plasma and small proteins bw gaps into interstitial fluid.
Serous exudate ensues. Clear with little plasma protein and few leukocytes in it.

Question 6

Delayed prolonged permeability

Answer 6

Vascular permeability delayed and then protracted. Eg. Sunburn.
Gaps between endothelial cells in venules and capillaries can be large and leak large amounts of plasma and plasma proteins.
Large plasma proteins such as fibrinogen enter the extra cellular tissue and get converted to fibrin.
Fibrinous exudate ensued, indicated higher degree of damage than serous.
Fibrin is normally lysed by the enzyme plasmin, which is generated when we form fibrin.

Question 7

Immediate prolonged permeability

Answer 7

Vascular permeability is increased immediately and remains for a long time.
Most severe injury, results in damage to all small blood vessels (venules, capillaries, and arterioles) and causes extensive leakage that can result in a fibrinous exudate or if in very severe trauma a combine fibrinous/ haemorrhagic exudate

Question 8

Suppurative/ purulent exudate

Answer 8

Mainly instigated by bacteria.
Large numbers of polymorphism infiltrate tissue to produce a white/ yellow exudate, pus.
Gaps between endothelial cells in venules and capillaries are quite large so large proteins such as fibrinogen will also escape into interstitial tissue to be converted to fibrin. Therefore, may lead to formation of scar.

Question 9

Chemotaxis

Answer 9

The movement of cells along a chemical gradient.

Question 10

Mediators from cells: histamine

Answer 10

Vasodilation

Increased permeability of venules

Question 11

Mediators from cells: serotonin

Answer 11

From platelets, cause vasoconstriction

Question 12

Beneficial effects of acute inflammation

Answer 12

Rid body of microbial infection
Remove dead cells in prep for healing
Create memory of foreign invaders

Question 13

Harmful effects of acute inflammation

Answer 13

May increase blood loss
Pain
Swelling may block hollow tubed organs
Swelling may reduce function of joints

Question 14

Inflammation

Answer 14

Vascular and cellular response to injury. 
-itis 
Acute- lasts a few weeks 
Sub acute - 3-4 weeks 
Chronic- months to years