Anatomical pathology lecture 3 Pleurisy - inflamed pleura Components of acute inflammation

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Anatomical pathology lecture 3

  • Pleurisy – inflamed pleura
  • Components of acute inflammation:
  1. vascular an increase in, but relatively static flow of blood (redness, heat)
  2. cellular an increase in the number of cells and sometimes haemorrhage (swelling)
  3. exudate a protein rich, plasma-like fluid containing fibrinogen which converts to fibrin (swelling, pain, loss of function)
  • cells of acute inflammation: polymorphs and macrophages
  • polymorph – alias polymorphonuclear leucocyte, poly, neutrophil or granulocytes. All blood granulocytes are composed of 80% neutrophils 10% eosinophils and 1% basophils.
  • Macrophages are large scavenger cell, synonymous with tissue histiocyte or
  • In blood – monocyte
  • In liver – Kupffer cell
  • In brain – microglia
  • Coalesce to form
  • Epithelioid cells and later giant cells
  • Post acute injury event sequence
  1. momentary arteriolar constriction
  2. dilation of small vessels
  3. increased permeability of small vessel walls
  4. escape of protein rich exudate fluid – oedema
  5. haemoconcentration, slowing of blood dynamics
  6. margination of leucocytes, along endothelium
  7. leucocyte emigration & diapedesis of red blood cells
  8. chemotaxis of polymorphs
  9. phagocytosis by and lysis of polymorphs
  10. arrival of phagocytic macrophages
  • chemotaxis – chemotropism, attraction to a chemical stimulus and movement toward that stimulus
  • diapediesis – the passive passage blood or any of its cell constituents through the intact wall of a blood vessel
  • phagocytosis – ingestion of foreign matter or debris by a polymorphs or macrophages
  • plasma cell – activated lymphocyte of the B series, which makes immunoglobulin
  • hallmarks of acute inflammation are:
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  • polymorphs
  • macrophages
  • fibrin
  • oedema
  • exceptions
  1. where lymphoid aggregates can be found you will always see lymphocytes eg. In GIT and bronchi
  2. viral infections, even in the acute response, no polymorphs are seen, only lymphocytes
  3. parasites infestation or allergen exposure, you will see polymorphs but als many eosinophils
  • mediators of vascular leakage arising from plasma
  • kinins (bradykinin)
  • anaphylatoxins, mainly causing histamine release
  • fibrinopeptides
  • mediator of vascular leakage arising from tissues
  • vasoactive amines (histamine, serotonin)
  • leukotrienes
  • prostaglandins
  • substance P
  • neurotensin
  • neutrophil lysosomal cationic proteins
  • Cellulitis – inflammation of cells. Usually refers ...

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