General Pathology Lecture 7: Acute Inflammation

What is the normal protective response of vascularized tissue to noxious stimulus or injury?

Inflammation

What are the four cardinal signs of inflammation?

1. Rubor (Redness)

2. Tumor (Swelling)

3. Calor (Heat)

4. Dolor (Pain)

What is the onset of acute inflammation described as?

Abrupt

What is the duration of acute inflammation described as?

Short

What two things is acute inflammation often associated with?

1. Sudden injury

2. Early repair

What kind of reaction is caused by acute inflammation?

Exudative reaction

Which three things arrive from the vasculature in an exudative reaction?

1. Fluid

2. Serum proteins

3. Leukocytes

In what two situations can acute inflammation become chronic inflammation?

1. Injury persists

2. Required for full repair

What kind of reaction is caused by chronic inflammation?

Proliferative reaction

Which three cells are proliferated in chronic inflammation?

1. Fibroblasts

2. Endothelial cells

3. Chronic inflammatory cells

What are the three inflammatory cells of chronic inflammation?

1. Macrophages

2. Lymphocytes

3. Plasma cells

When does chronic inflammation resolve? (2)

1. Source of injury is removed

2. Tissue finishes remodeling

What are the vascular hallmarks of acute inflammation?

1. Increase blood flow

2. Increase vascular permeability of fluid and plasma

What are the cellular hallmarks of acute inflammation?

Recruitment and stimulation of inflammatory cells

What are the four steps of acute inflammation after bacteria enters the wound?

1. Platelets release blood-clotting proteins

2. Mast cells mediate vasodilation

3. Neutrophils and macrophages kill bacteria

4. Inflammation continues until wound is repaired

What do macrophages secrete to attract immune cells to the site of injury?

Cytokines

What are the two vascular responses to injury?

1. Increased permeability

2. Slow down

What does increased vascular permeability allow for?

Filter and deliver soluble factors to injury site

Why does the vascular system slow down as a response to injury?

Concentrates supplies to areas of need

Which two cardinal signs are caused by vasodilation?

1. Rubor

2. Calor

Which two cardinal signs are caused by increased vascular permeability causing exudation of fluid?

1. Tumor

2. Dolor

Why does increased vascular permeability cause pain?

Tissue distension that compresses nerve endings

What are the three systemic signs of acute inflammation?

1. Fever

2. Leukocytosis

3. Lymphadenopathy

The production of what causes fevers?

Endogenous pyrogens

What is caused by leukocytosis?

Increase in white blood cell number

What is caused by lymphadenopathy?

Increased production of immune cells

What is the initial response of vasculature to injury before dilation?

Transient vasoconstriction

What is the purpose of vasodilation?

Increase local blood flow

How much can local blood flow increase through vasodilation?

10x

What condition is caused by vasodilation?

Erythema

How does vasculature leak fluid into the extravascular space? (2)

1. Endothelial cell retraction

2. Gap formation

What is the degree of leaking of vasculature dependent on?

Severity of injury

What happens to fluid from vessels in vascular stasis?

Lost without losing blood cells

What happens to blood viscosity in vascular stasis?

Increases

What happens to blood flow in vascular stasis?

Slows

What is the action of leukocytes during vascular stasis?

Leukocyte margination

What follows stasis after an injury?

Leukocyte extravasation to injury site

What causes the initial capture of leukocytes during leukocyte margination?

Selectins

What allows leukocytes to cross the membrane during leukocyte margination?

Integrins

What are the selectins that causes rolling in leukocyte margination?

L-selectin

What are the selectins that causes adherence in leukocyte margination?

ICAM-1

What is swelling from fluid leakage called?

Inflammatory edema

What is the thin, clear, watery fluid released during mild inflammation?

Serous exudate

What is serous exudate mainly made of?

Plasma proteins with low proteins

Which edema fluid is thick and opaque yellow pus?

Purulent exudate

What two things is purulent exudate rich in?

1. Neutrophils

2. Cell debris

What are the two methods of draining purulent exudate?

1. Fistulous tract

2. Incision

What is the main role of edema?

Dilute toxins in tissue

How does edema inactivate toxins?

Proteolysis

What does edema contain that serves as a scaffold for movement of inflammatory cells and initiates repair?

Fibrinogen

What are the two inflammatory cell actions?

1. Chemotaxis

2. Phagocytosis

What is the directed movement of white blood cells to the area of injury called?

Chemotaxis

What is 60 - 70% of white blood cells in the body?

Neutrophils

What is the primary action of neutrophils?

Phagocytosis

Is the half life of neutrophils long or short?

Short

What is the nucleus of neutrophils described as?

Multilobular

What does the granular cytoplasm of neutrophils contain?

Lysozymes

What is the second line of response to injury in acute inflammation?

Monocytes

What is 3 - 8% of white blood cells in the body?

Monocytes

What is the nucleus of monocytes described as?

Large mononuclear

What component of monocytes allow phagocytosis?

Lysozymes

What do monocytes become when they migrate out of the blood stream?

Macrophages

What do monocytes regulate?

Switch from acute to chronic inflammation

What condition does the vasoactive mediators lead to?

Edema

What condition does the chemotactic factors lead to?

Inflammation