Ch 43 Blood plasma proteins, coagulation, and fibrinolysis Flashcards
Where are most of the plasma proteins produced?
liver
What is the difference between plasma and serum? Which is physiologic?
Plasma- nutrients, metabolites, electrolytes, and hormones are all carried in the noncellular fraction of the blood. Serum- an amber-colored, protein-rich liquid that separates out when blood coagulates. Plasma is physiologic
What is the major plasma protein?
albumin
What is the role of haptoglobin?
binds extracorpuscular heme
What exerts osmotic pressure in the plasma?
plasma proteins (albumin is 60% total plasma protein)
What is hydrostatic pressure? Where does this pressure come from?
Hydrostatic pressure is the pressure that is exerted by a fluid at equilibrium at a given point within the fluid, due to the force of gravity. In the arteriolar end of the capillaries, it exceeds the sum of the tissue pressure and the osmotic pressure of the plasma proteins. Thus water tends to leave the capillaries and enter extravascular spaces.
Which has the highest hydrostatic pressure: arterioles or venules?
Arterioles (37 mmHg ) venules have (17 mm Hg)
What is the predicted result of low plasma protein concentration? What are their functions?
poor clotting, edema
(their functions include: maintaining the proper distribution of water between the blood and tissues; transporting nutrients, metabolites, and hormones throughout the body; defending against infection; and maintaining the integrity of the circulation through clotting.
What type of proteins are most plasma proteins?
glycoproteins
What percent of the plasma protein is albumin?
60%
What two things trigger activation of the complement system?
First, Interaction with antigen-antibody complexes, and second (specific for bacterial infections) interaction of bacterial cell polysaccharides with complement protein C3b.
How do proteins in the complement system become activated?
proteolytic activation cascade of proteins of the complement system, resulting in a release of biologically active peptides or polypeptide fragments
What type of cells are attracted to activated complement?
phagocytic cells
What blood components act inhibit complement activation?
Activated neutrophils release lysosomal proteases from their granules that can attack elastin, the various types of collagen, and other extracellular matrix proteins. The plasma proteins alpha1-antitrypsin and alpha2-macroglobulin limit proteolytic damage by forming noncovalent complexes with the proteases, thereby inactivating them. (However, the product of neutrophil myeloperoxidase, HOCl, inactivates the protease inhibitors, thereby ensuring that the proteases active at the site of infection.)
What cell type initiates clotting?
platelets
What triggers the first step of clotting? Which pathway is this?
Adhesion of platelets to to the subendothelial cell layer. Platelet activation pathway
Name two compounds that are uncovered when vascular damage occurs.
collagen and subendothelial matrix-bound vWF
Describe con Willebrand factor. Is it a protein, carbohydrate, fat or other?
A vWF is a large multimeric glycoprotein with a subunit MW of 220 kDa. Its size in circulation ranges between 500 and 20 kDa, and its role in circulation is to stabilize factor VIII and protect it from degradation. It is synthesized in endothelial cells and megakaryocytes and is located in the subendothelial matric, in specific platelet granules, and in the circulation bound to Factor VIII.
What two cell types synthesize vWF?
megakaryocyte, endothelial cells
Where else besides in the cells that synthesize vWF (megakarycote and endothelial cells) is it found?
subendothelial matric and in specific platelet granules
Name three steps of platelet activation
adhesion, aggregation, and secretion
What happens in the first step of platelet activation?
platelets adhere to subendothelial GPIa through binding to collagen
What happens in the second step of platelet activation?
Platelets adhere to subendothelial GPIb through binding to vWF
What happens in the third step of platelet activation?
The second binding event exposes the GPIIb-GPIIIa complex in the platelet membrane, which can also bind to vWF and fibrinogen.
