Ch 43 Blood plasma proteins, coagulation, and fibrinolysis

Question 1

Where are most of the plasma proteins produced?

Answer 1

liver

Question 2

What is the difference between plasma and serum? Which is physiologic?

Answer 2

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

Question 3

What is the major plasma protein?

Answer 3

albumin

Question 4

What is the role of haptoglobin?

Answer 4

binds extracorpuscular heme

Question 5

What exerts osmotic pressure in the plasma?

Answer 5

plasma proteins (albumin is 60% total plasma protein)

Question 6

What is hydrostatic pressure? Where does this pressure come from?

Answer 6

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.

Question 7

Which has the highest hydrostatic pressure: arterioles or venules?

Answer 7

Arterioles (37 mmHg ) venules have (17 mm Hg)

Question 8

What is the predicted result of low plasma protein concentration? What are their functions?

Answer 8

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.

Question 9

What type of proteins are most plasma proteins?

Answer 9

glycoproteins

Question 10

What percent of the plasma protein is albumin?

Answer 10

60%

Question 11

What two things trigger activation of the complement system?

Answer 11

First, Interaction with antigen-antibody complexes, and second (specific for bacterial infections) interaction of bacterial cell polysaccharides with complement protein C3b.

Question 12

How do proteins in the complement system become activated?

Answer 12

proteolytic activation cascade of proteins of the complement system, resulting in a release of biologically active peptides or polypeptide fragments

Question 13

What type of cells are attracted to activated complement?

Answer 13

phagocytic cells

Question 14

What blood components act inhibit complement activation?

Answer 14

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.)

Question 15

What cell type initiates clotting?

Answer 15

platelets

Question 16

What triggers the first step of clotting? Which pathway is this?

Answer 16

Adhesion of platelets to to the subendothelial cell layer. Platelet activation pathway

Question 17

Name two compounds that are uncovered when vascular damage occurs.

Answer 17

collagen and subendothelial matrix-bound vWF

Question 18

Describe con Willebrand factor. Is it a protein, carbohydrate, fat or other?

Answer 18

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.

Question 19

What two cell types synthesize vWF?

Answer 19

megakaryocyte, endothelial cells

Question 20

Where else besides in the cells that synthesize vWF (megakarycote and endothelial cells) is it found?

Answer 20

subendothelial matric and in specific platelet granules

Question 21

Name three steps of platelet activation

Answer 21

adhesion, aggregation, and secretion

Question 22

What happens in the first step of platelet activation?

Answer 22

platelets adhere to subendothelial GPIa through binding to collagen

Question 23

What happens in the second step of platelet activation?

Answer 23

Platelets adhere to subendothelial GPIb through binding to vWF

Question 24

What happens in the third step of platelet activation?

Answer 24

The second binding event exposes the GPIIb-GPIIIa complex in the platelet membrane, which can also bind to vWF and fibrinogen.

Question 25

Name three types of granules found in platelets.

Answer 25

1. Electron-dense containing: Ca2+, ADP, ATP, serotonin
2. alpha-granule containing: heparin antagonist, PDGF, b-thromboglobulin, vWF, fibrinogen, other clotting factors 3. Lysosomal granules, which contain hydrolytic enzyme

Question 26

Name two things released by platelets that cause vasoconstriction

Answer 26

serotonin and thromboxane A2