CV 5 (2)

Question 1

A person is Rh-positive if they have the

Answer 1

Rh Antigen on RBCs

– No Rh-antibodies in the plasma

Question 2

A person is Rh-negative if they lack the

Answer 2

Rh Antigen on RBCs

– No Rh-antibodies (IgGs) in the plasma

Question 3

– No Rh-antibodies (IgGs) in the plasma IF the person

has never been exposed to Rh+ blood (2)

Answer 3

• May see a mild agglutination response 2-4 weeks
after Rh-negative person receives Rh+ RBCs
• Usually the first response, if it occurs, is mild

Question 4

Erythroblastosis Fetalis

Answer 4

Rh-negative mother, Rh-positive fetus.

Question 5

Erythroblastosis Fetalis

First pregnancy: (3)

Answer 5

fetal red cells leak into maternal circulation.
– Mother develops anti-Rh antibodies.
– Low risk to fetus because this occurs late in
pregnancy.

Question 6

Erythroblastosis Fetalis

Second pregnancy:

Answer 6

maternal IgG crosses placenta, destroys fetal RBC’s.

Question 7

Erythroblastosis Fetalis

Treatment:

Answer 7

administration of anti-RhD immunoglobulin (RhoGAM) after delivery.

Question 8

Platelets

Answer 8

Cytoplasmic fragments derived from megakaryocytes (thrombocytes).

Question 9

Platelets concentration in blood

Answer 9

150,000 – 300,000/μl of blood

Question 10

platelet lifespan

Answer 10

10 days

Question 11

platelet primary role in

Answer 11

hemostasis

Question 12

platelet content

Answer 12

no nuclei, cannot divide

Question 13

platelets contain (5)

Answer 13

• Actin and myosin
• Enzymes and organelles for aerobic CR
• Enzymes for Prostaglandin synthesis
• Fibrin – stabilizing factor (important for hemostasis)
• Growth factors that stimulate endothelial cell, VSM, and fibroblasts to divide and grow

Question 14

Recent evidence that platelets can act as (2)

Answer 14

immune cells and contribute to

the inflammatory process of atherosclerosis

Question 15

Hemostasis

Answer 15

The physiological mechanisms that stops bleeding

Question 16

Hemostasis is a 4-step process:

Answer 16

1. Vasoconstriction of damaged vessel to decrease blood flow and pressure
2. Formation of platelet plug to block hole in damaged vessel
3. Clot formation (requires Fibrin)
4. Clot dissolution

Question 17

Steps Leading to Platelet Plug and Vasoconstriction

Answer 17

 Platelets stick to damaged Endothelial cell surface (Von Willebrand Factor (vWF))

1. Platelets release contents of secretory vesicles
2. Stimulate production of Thromboxane A2 from platelet plasma membrane

Question 18

Causes of platelet plug/vasoconstriction (2)

Answer 18

1. Vasoconstriction of damaged vessel

2. Platelet plug formation (+ feedback Platelet activation)

Question 19

Clotting =

Answer 19

coagulation

– Blood converted into solid gel called clot or thrombus

Question 20

Blood Clot occurs around

Answer 20

platelet plug

Question 21

Blood Clot fxn

Answer 21

to support and reinforce platelet plug

Question 22

Blood Clot defense mechanism

Answer 22

dominant hemostatic defense mechanism

Question 23

Clotting Factors =

Answer 23

Zymogens

Question 24

ntrinsic Pathway

 Activated when there is: (2)

Answer 24

• trauma to blood
• blood comes in contact with collagen from traumatized blood vessel wall

 All required factors found within the blood

Question 25

Extrinsic Pathway  Activated when there is: (2)  Requires:

Answer 25

- trauma to vascular wall - trauma to surrounding extravascular tissue. Tissue Factor (Thromboplastin) produced by cells located outside of endothelial cells

Question 26

Normally, thrombus formation begins with

Answer 26

extrinsic pathway followed by intrinsic | activation by Thrombin

Question 27

Step 4: Fibrinolysis (4)

Answer 27

```  The plasma protein plasminogen is trapped in a clot just like other plasma proteins  Over time, injured tissues and endothelial cells slowly release tissue plasminogen factor (t- PA)  t-PA converts plasminogen to plasmin a few days after clot is formed  Plasmin digests fibrin fibers, fibrinogen, prothrombin, and Factors V, VIII, and XII ```

Question 28

A thrombus is a

Answer 28

clot that forms and persists in an | unbroken blood vessel.

Question 29

Thrombus can block the vessel; leads to

Answer 29

ischemia and tissue death downstream from the clot (i.e., cause of fatal heart attacks).

Question 30

Embolus is a

Answer 30

free floating object in the blood stream; can | wedge and occlude a vessel (referred to as an embolism).

Question 31

Pulmonary embolism impair

Answer 31

oxygenation

Question 32

cerebral embolism cause

Answer 32

strokes

Question 33

Anticoagulants (6)

Answer 33

``` Aspirin Heparin Recombinant t-PA Warfarin Dabigatrin etexilate (Pradaxa) Clopidogrel (Plavix) ```

Question 34

Aspirin ‒ Low doses - Inhibit formation of ‒ High doses - Inhibit formation of

Answer 34

thromboxane A2 by platelets but not prostacyclin by endothelium prostacyclin

Question 35

Heparin

Answer 35

‒ Binds to Antithrombin III and increases its activity by 100-1000x

Question 36

Recombinant t-PA

Answer 36

– Dissolve intravascular clots if given immediately

Question 37

Warfarin

Answer 37

‒ Blocks vitamin K

Question 38

Dabigatrin etexilate (Pradaxa)

Answer 38

‒ Blocks active site of thrombin

Question 39

Clopidogrel (Plavix)

Answer 39

‒ Blocks platelet activation

Question 40

Thrombocytopenia what is it? what causes it? (2) treatment?

Answer 40

 is characterized by a lack of platelets, causes spontaneous bleeding in small blood vessels.  Even normal movement causes internal hemorrhaging (petechiae) in the skin.  Anything that affects bone marrow can cause this (chemotherapy, irradiation etc.).  The only treatment is platelet transfusion.

Question 41

Liver Disease what is it?  Severe cases like total impairment of liver function associated with

Answer 41

 Impaired liver function causes a lack of zymogens cirrhosis and hepatitis can require transfusions.

Question 42

Hemophilia

Answer 42

– Genetic disorder caused by deficiency of gene | for specific coagulation factor (Factor VIII is most common form)

Question 43

Von Willebrand’s disease (2)

Answer 43

– Reduced levels of vWf | – Decreases platelet plug formation

Question 44

Vitamin K deficiencies (2)

Answer 44

– Decreased synthesis of clotting factors | – Newborns (Vitamin K shots)

Question 45

activated partial thromboplastin time (PTT/aPTT)

Answer 45

assessment of intrinsic pathway

Question 46

prothrombin time (PT)

Answer 46

assessment of extrinsic pathway

Question 47

Citrate is added to prevent blood from clotting as it will

Answer 47

bind to calcium ions. Except for the first two steps in the intrinsic pathway, calcium ions are required for all blood-clotting reactions.

Question 48

INR=International Normalized Ratio. (6)

Answer 48

``` PT times Tissue factor is isolated from human tissue (like placenta) Can have a wide range of activities between batches. INR allows individual tests to be normalized. Each batch comes with a normal PT time  Patient values compared to normalized PT time provided (INR = PTpatient/PTnormal) ```

Question 49

If INR: < 1.1 ~ 2 - 4 (3) > 4 (2)

Answer 49

– normal blood clotting ‒Blood clots 2-4x slower than normal ‒Effective therapeutic range ‒OK for Dental work ‒Risk of bleeding too great ‒Work with physician