1.1 Blood 12-23 Flashcards
What is the pH of blood?
7.4
What is the temperature of blood?
37 degrees C or 98.6 degrees F
Blood is ______ times more viscous than water
3-5
On average, there is about ____ liters of blood in the body.
5
hematocrit is a commonly measure laboratory parameter to measure the proportion of _____ in the blood.
RBC’s/erythrocytes
What is the normal hematocrit?
45% +/- 5
Decreased hematocrit would indicate _____.
anemia
Increased hematocrit would indicate _____.
polycythemia
What can cause polycythemia?
dehydration
living at high altitudes
disease
RBC number is controlled by ______ which is produced primarily in the ______.
erythropoietin : kidneys
What percentage of blood volume is plasma proteins?
55%
What are the three broad groups of plasma proteins? Where are they made?
albumin
globulins
fibrinogen
made primarily in the liver
The most common and smallest plasma protein that is the main contributor to plasma colloidal osmotic pressure.
albumin
What is the function of colloidal osmotic pressure?
to prevent excessive fluid filtration
A lack of plasma proteins due to starvation, liver disease, nephrosis or intestinal malabsorption is called_____ and would have what affect?
hypoproteinemia: decreased plasma protein would result in decreased colloidal osmotic pressure and increased loss of fluid from capillaries leading to edema
What are alpha globulins?
a family of mostly carrier proteins and clotting factors but also some HDL and steroid binding proteins
What are beta globulins?
a family of carrier proteins, LDL and iron as transferrin
What are gamma globulins?
a family of antibodies
What is fibrinogen?
the main protein precursor to fibrin which forms a clot
The ability of blood to maintain its volume is called _____.
hemostasis
Hemostasis is made possible by what key mechanisms?
vascular constriction
platelet plugs
clot formation
Thrombin functions through what kind of signal transduction?
IP3/DG
Trauma to vessel walls induces vasoconstriction by the release of _____ from smaller vessels. Platelets, after they aggregate also release _______ and ________ that stimulate vasoconstriction
Endothelin-1: thromboxane A2 and serotonin
______ from tissues and ______ from the clotting process itself, both promote platelet aggregation to form a plug.
thromboxane : thrombin
What are the three phases of platelet plug formation?
- platelet adherence: exposed tissue proteins such as collagen and their secretion of VonWillebrand factor cause platelets to adhere to the damaged endothelia
- platelet aggregation: thromboxane and thrombin promote platelet aggregation to form a plug
- platelet secretion: ongoing secretions of serotonin promotes vasoconstriction
How does aspirin act as a blood thinner?
by inhibiting platelet aggregation
The clotting/coagulation cascade of fibrinogen to fibrin causes ______.
amplification (activation of just a few starter molecules can result in many thousands of products being produced)
What are the anti clotting mechanisms that provide negative feedback?
- endothelial linings are engineered to minimize clotting with glycocalyx that repels clotting factors
- consumption of clotting factors by antithrombin III which binds and inactivates thrombin
- fibrinolysis which is destruction of fibrin and other clotting factors by the protease plasmin
Plasminogen is converted to its active form, plasmin, by ______.
tissue plasminogen activator tPA
Factor I in the clotting cascade is also known as ________. What is it’s active form?
Fibrinogen, Fibrin
Factor II in the clotting cascade is also known as _______. What is its active form?
Prothrombin, Thrombin
Factor III in the clotting cascade is also known as ________.
Tissue factor
Prothrombin activator is a complex substance made of several substances. What are those substances?
Factor X (predominantly)
Factor Va
Factor IV, aka calcium
Prothrombin/Factor II is activated by two mechanisms. What are they? Which happens faster? Which is more powerful at amplification?
1: intrinsic pathway is more powerful at amplification
2: extrinsic pathway is much faster
In the Intrinsic pathway, what factors are required to activate Factor X and therefore activate prothrombin to thrombin?
Factor IX and VIIIa (9 and 8)
*calcium also needed
In the extrinsic pathway, what factors are required to activate Factor X and therefore activate prothrombin to thrombin?
Factor III/tissue factor and Factor VII (3 and 7)
The initial formation of thrombin through the extrinsic pathway, which is must faster, allows thrombin to have positive feedback on several factors in the coagulation cascade. 3 of them are in the intrinsic pathway, 1 in the extrinsic pathway and 1 in the final step of fibrin polymer formation. What are these 5 factors that thrombin has positive feedback on?
In the intrinsic pathway: Factor 5,8,11 In the extrinsic pathway: Factor 7 In fibrin polymerization: Factor 13/fibrin stabilizing factor
The amplified formation of thrombin through the intrinsic pathway, which is must slower, allows abundant concentrations of thrombin to have negative feedback in the coagulation cascade. What 2 processes does thrombin inhibit?
- the conversion of factor X to it’s active form
- the conversion of prothrombin to thrombin
In addition to the negative feedback mechanisms that thrombin has, it also activates two other enzymes. What are these enzymes and what do they do?
Antithrombin - plasma protein that binds and inactivates thrombin
Plasmin (from plasminogen) - protease that degrades fibrin
Which enzyme is responsible for fibrinolysis?
Plasmin
Which protein is both activated by thrombin and binds to thrombin to inactivate it?
Antithrombin
