Aims

• Differentiate acute vs. chronic inflammation.

• Differentiate apoptosis vs. necrosis.

• Readings: Robbins, Chapters 1 & 2

Terms

• Cytokine- Secreted proteins that function as mediators of immune and inflammatory reactions. Secreted primarily by macrophages, NK cells, and T-cells.

• Chemokine- Family of low molecular weight cytokines that stimulate leukocyte movement and regulate migration of leukocytes from blood to tissues.

Robbins Basic Pathology 2-8

Relationship between Acute and Chronic Inflammation

Robbins’ Basic Pathology 2-8 7th Ed. & 2-5 8th Ed.

Inflammation Chronology

Adapted from Robbins’ Basic Pathology 2-2

Major Manifestations of Acute Inflammation

• Vascular changes– Vascular

_________________________• Resulting in increased blood flow.

– Extravasation of fluid and plasma proteins

• Results in edema an deposition of plasma proteins.

• Cellular events– Leukocyte extravasation and

accumulation

Robbins’ Pathologic Basis of Disease Table 3-6

Mediators of Inflammation

Robbins’ Basic Pathology 2-24 7th Ed.

Serous inflammationskin blisterfluid edema

Histology of Acute Inflammation

Robbins’ Basic Pathology 2-4 7th Ed.

Fibrinous inflammationfibrin leaks out of vessels

Histology of Acute Inflammation

Ulcerationssurface of an organshedding of necrotic tissue

Suppurative inflammationPus = PMNs, edema, necrotic cell debris

Vascular Changes Following an Injury

• Transient vasoconstriction (seconds) followed by vasodilation.– Results in increased blood flow.

• Slowing of blood flow.– Due to increased vascular permeability.

• Leukocyte margination.– Leading to leukocyte extravasation.

Adapted from Robbins’ Basic Pathology 2-3 7th Ed.

Edema

• Hydrostatic pressure– ______________________

in inflammation.• Due to dilation of arterioles

resulting in more blood flow to capillaries.

• Colloid osmotic pressure– Decreases in inflammation.

• Due to loss of plasma proteins into interstitial fluid.

Robbins’ Basic Pathology 2-19 7th Ed. & 2-9 8th Ed.

Resolution of Inflammation• Return to normal

permeability.

• Drainage of edema into lymphatic vessels.

• Pinocytosis/phagocytosis of edema fluid.

• Phagocytosis of PMNs and debris by macrophages.

Sherwood’s Human Physiology 12-2

Summary of Acute Inflammation