Book contents
- Frontmatter
- Contents
- List of contributors
- Editors' preface
- PART I PHYSIOLOGY
- 1 History of platelets
- 2 Production of platelets
- 3 Morphology and ultrastructure of platelets
- 4 Platelet heterogeneity: physiology and pathological consequences
- 5 Platelet membrane proteins as adhesion receptors
- 6 Dynamics of the platelet cytoskeleton
- 7 Platelet organelles
- 8 Platelet receptors for thrombin
- 9 Platelet receptors: ADP
- 10 Platelet receptors: prostanoids
- 11 Platelet receptors: collagen
- 12 Platelet receptors: von Willebrand factor
- 13 Platelet receptors: fibrinogen
- 14 Platelet signalling: GTP-binding proteins
- 15 Platelet phospholipases A2
- 16 Roles of phospholipase C and phospholipase D in receptor-mediated platelet activation
- 17 Platelet signalling: calcium
- 18 Platelet signalling: protein kinase C
- 19 Platelet signalling: tyrosine kinases
- 20 Platelet signalling: cAMP and cGMP
- 21 Platelet adhesion
- 22 The platelet shape change
- 23 Aggregation
- 24 Amplification loops: release reaction
- 25 Amplification loops: thromboxane generation
- 26 Platelet procoagulant activities: the amplification loops between platelets and the plasmatic clotting system
- 27 Platelets and chemotaxis
- 28 Platelet–leukocyte interactions relevant to vascular damage and thrombosis
- 29 Vascular control of platelet function
- PART II METHODOLOGY
- PART III PATHOLOGY
- PART IV PHARMOLOGY
- PART V THERAPY
- Afterword: Platelets: a personal story
- Index
- Plate section
3 - Morphology and ultrastructure of platelets
from PART I - PHYSIOLOGY
Published online by Cambridge University Press: 10 May 2010
- Frontmatter
- Contents
- List of contributors
- Editors' preface
- PART I PHYSIOLOGY
- 1 History of platelets
- 2 Production of platelets
- 3 Morphology and ultrastructure of platelets
- 4 Platelet heterogeneity: physiology and pathological consequences
- 5 Platelet membrane proteins as adhesion receptors
- 6 Dynamics of the platelet cytoskeleton
- 7 Platelet organelles
- 8 Platelet receptors for thrombin
- 9 Platelet receptors: ADP
- 10 Platelet receptors: prostanoids
- 11 Platelet receptors: collagen
- 12 Platelet receptors: von Willebrand factor
- 13 Platelet receptors: fibrinogen
- 14 Platelet signalling: GTP-binding proteins
- 15 Platelet phospholipases A2
- 16 Roles of phospholipase C and phospholipase D in receptor-mediated platelet activation
- 17 Platelet signalling: calcium
- 18 Platelet signalling: protein kinase C
- 19 Platelet signalling: tyrosine kinases
- 20 Platelet signalling: cAMP and cGMP
- 21 Platelet adhesion
- 22 The platelet shape change
- 23 Aggregation
- 24 Amplification loops: release reaction
- 25 Amplification loops: thromboxane generation
- 26 Platelet procoagulant activities: the amplification loops between platelets and the plasmatic clotting system
- 27 Platelets and chemotaxis
- 28 Platelet–leukocyte interactions relevant to vascular damage and thrombosis
- 29 Vascular control of platelet function
- PART II METHODOLOGY
- PART III PATHOLOGY
- PART IV PHARMOLOGY
- PART V THERAPY
- Afterword: Platelets: a personal story
- Index
- Plate section
Summary
Introduction
Platelets are deceptively simple cells. Their small size, lack of a nucleus and clear cytoplasm made recognition difficult for early microscopists. As a result, platelets were the last of the cellular elements of circulating blood to be identified. Also, recognition was not helped by the tendency of platelets to remain nondescript. They hide as far from the centre of the flowing column of blood as possible. Other cells are busy carrying oxygen and removing carbon dioxide, supplying nutrients, transporting waste, reacting to foreign invaders or leaving the circulation to participate in inflammatory and immunological responses, but not platelets. This cell desires anonymity and remains as quiet as possible as it rolls along the intact endothelium for its 10 to 12 day lifespan. If it can retire to the spleen without becoming involved in any physiologic activity, the platelet's life can be considered a complete success.
Thus, in this sense the platelet has no function in the circulation, except one: to be there when it is needed to keep blood flowing. It is the sentinel on guard at all times to react immediately at sites of vascular injury as soon as subendothelium is exposed. Within microseconds, platelets undergo dramatic changes in their morphology and biochemistry, fill the site of damage with aggregates to form a hemostatic plug, contract to prevent further loss of blood and restore integrity to the vascular system.
- Type
- Chapter
- Information
- Platelets in Thrombotic and Non-Thrombotic DisordersPathophysiology, Pharmacology and Therapeutics, pp. 41 - 69Publisher: Cambridge University PressPrint publication year: 2002
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