Lecture 12: Blood Flashcards
Thrombin activates
Factor V
Platelets
Derived from megakaryocytes
200-400k per microliter of blood
Enhance aggregation by release of factors, promote clot formation, retraction, and dissolution
Repair damage to endothelium by forming platelet plug
Lymphocyte characteristics
Large, round, sometimes slightly indented nucleus (fills most of cell)
Variation in cell size
B-lymphocytes-precursor of plasma cells
T-lymphocytes
Erythrocyte (RBC) characteristics
Numbers increase under influence of erythropoietin
Devoid of granules and ORGANELLES
Peripheral proteins include spectrin and actin
Von willebrand factor
Plasma protein (released from Weibel-Palade bodies in endothelial cells) that facilitates the adherence of platelets to the walls of damaged blood vessels
Formation of platelet plug step one
Platelets adhere to exposed collagen (after endothelial lining is disrupted by injury) and release contents of their secretory vesicles, including ADP, and also cause the conversion of arachidonic acid in the platelet plasma membrane to thromboxane A2, which further stimulates platelet aggregation
Kallikrein is involved in
Formation of bradykinin and conversion of plasminogen to plasmin
-Can feedback and activate more Factor XII
Prothrombin is activated by
Factor XII
Intrinsic pathway
Typically initiated by injury to the endothelium of the blood vessel, exposing collagen. Everything necessary for it to occur is already within the blood
RBC membrane proteins & function
Ankyrin- links the spectrin-actin network and the plasma membrane by binding to spectrin and a transmembrane band
Protein 4.1- link that binds spectrin-actin junctions and transmembrane protein glycophorin
Major structural protein of RBCs
Spectrin
Hemostatic sequence of events (in small vessels)
Constriction of smooth muscles around vessels Constriction of vessels Slowing of blood Formation of platelet plug Blood clotting (coagulation)
Endothelial cells release
Prostacyclin- decreases platelet aggregation
Vitamin K is necessary for synthesis of
Factors VII, IX and X
Albumins
Made in liver
Exert major osmotic pressure on blood vessel walls
BC step four
Reshaping of the clot by polymerization of fibrin
Adhesion of platelets involves
Integrin
Factor XII is activated when
When it contacts collagen in the damaged vessel wall
Eosinophil characteristics
Lobulated (bilobed) nucleus
Specific granules (Major basic protein, peroxidase, cationic protein)
Respond in allergic diseases and parasitic infections
Phagocytize antibody-antigen complexes and parasites
Factor XII converts x-y
Prekallikrein to kallikrein
Basophilic granules contain
Vasoactive substances
- Serotonin
- Heparin (anticoagulant)
- Kallikrein (attracts eosinophils)
Most clotting factors are synthesized in the
Liver
RBC structure
Tetramer of two polypeptide chains
Ends of spectrin tetramers associate with short actin filaments creating spectrin-actin network
Monocyte characteristics
Largest leukocytes
Eccentrically located, kidney shaped nucleus
Granular cytoplasm due to small lysosomes
Precursor of macrophages and osteoclasts
Fibrinogens
Made in liver
Function in blood clotting
Target for thrombin
Formation of platelet plug step two
ADP and other factors cause the platelets to aggregate, forming plug
BC step five
Dissolution of fibrin clots through activation of the plasminogen activator system and the action of plasmin
-this is called fibrinolysis
Hematoma
Accumulation of blood in tissues
Neutrophil characteristics
Active amoeboid phagocytes
Small, numerous specific granules
Larger, less numerous azurophilic granules
Remain in circulation for 10-12 hours, live for 1-2 days after leaving circulation
Secrete a class of enzymes capable of destroying certain bacteria
BC step two
Conversion of prothrombin to thrombin
BC step three
Conversion of fibrinogen to fibrin by thrombin
Basophil characteristics
Lobulated (bilobed) nucleus
Large, membrane bound basophilic granules
Thromboplastin
Membrane-bound lipoprotein expressed at sites of cell injury
Derived from membranes of damaged cells
Blood clot is dissolved by
Plasmin and t-PA
Platelets release
Thromboxane- increases platelet aggregation
Plasma
Blood minus the formed elements
Serum
Plasma without the blood-clotting proteins
Extrinsic pathway steps
Thromboplastin leads to the activation of Factor VII
Factor VII + Calcium + Thromboplastin activates Factor X
BC step one
Activation of prothrombin
Basophilic granules can produce
Leukotrienes
- Increase vascular permeability
- Slow contraction of smooth muscles
Extrinsic pathway
Involves the formation of tissue factor (thromboplastin or Factor III)
Major contents of Erythrocytes (RBCs)
Lipids
ATP
Carbonic anhydrase
Hemoglobin
