A & P - Cardiovascular System, The Blood - Hemostasis

Front 1

What are the two major types of stem cells that arise from the pluripotent stem cell in the bone marrow?

Back 1

Myeloid stem cell and lymphoid stem cell

Front 2

From which stem cell do platelets ultimately arise?

Back 2

Myeloid stem cell

Front 3

What larger cell are platelets fragments of?

Back 3

Megakaryocyte

Front 4

What is the hormone that influences the myeloid stem cell to develop into megakaryocyte-colony-forming cells that in turn develop into megakaryocytes?

Back 4

Thrombopoeitin (TPO)

Front 5

Which organ is responsible for synthesizing thrombopoeitin?

Back 5

Liver

Front 6

What is the lifespan of a platelet?

Back 6

5-9 days

Front 7

How are old platelets removed from circulation?

Back 7

Macrophages in the spleen and liver

Front 8

What is hemostasis?

What are the three aspects of hemostasis?

Back 8

Hemostasis refers to the process whereby bleeding is halted in a closed circulatory system.

The three aspects of hemostasis are:

1) Vascular spasm

2) Platelet plug formation

3) Blood clotting (coagulation)

Front 9

What is primary hemostasis?

Back 9

Primary hemostasis describes the interaction between platelets, von Willebrand factor (vWF), and the vessel wall to form a platelet plug at the site of vascular injury.

In other words, primary hemostasis = platelet plug formation.

Front 10

What is secondary hemostasis?

Back 10

Secondary hemostasis describes the propagation and amplification of the coagulation cascade culminating in the formation of fibrin threads.

Secondary hemostasis is also called clotting or coagulation.

Front 11

What is the initial step in the formation of a platelet plug?

Back 11

Exposure to normally subendothelial collagen causes some platelets to become activated. These activated platelets then activate other platelets.

Front 12

o What happens when a platelet becomes “activated”?

Back 12

o It releases its vesicles. These vesicles contain factors such as the prostaglandin thromboxane A2 that activate other platelets.

o It expresses molecules on its surface that allow cause it to become sticky (stick to other platelets, damaged vessel wall)

Front 13

o If you could choose a word to describe an activated platelet, what would it be?

Back 13

o Sticky

Front 14

What molecule plays an important role in the platelets' ability to stick to one another?

Back 14

vWF, or von Willibrand Factor

Front 15

What's the term for the gathering together of platelets?

Back 15

Platelet aggregation

Front 16

What is blood?

What is plasma?

What is serum?

Back 16

Blood consists of 1) a watery extracellular matrix containing dissolved substances and 2) formed elements (e.g. erythrocytes)

Plasma is blood minus the formed elements (cells and cell fragments). In other words, plasma is the watery extracellular matrix that contains certain dissolved substances.

Serum is plasma minus the clotting factors.

Front 17

What is coagulation?

Back 17

Coagulation is synonymous with secondary hemostasis, or the propagation and amplification of the clotting cascade that culminates in formation of fibrin threads.

Front 18

What is thrombosis?

Back 18

Thrombosis is pathologic coagulation in an undamaged blood vessel.

Front 19

What is the end product of the coagulation cascade?

Back 19

Fibrin

Front 20

What are the three pathways of the coagulation cascade?

Back 20

Intrinsic pathway, extrinsic pathway, and common pathway

Front 21

When do the intrinsic pathway and the extrinsic pathway become the common pathway?

Back 21

Both the intrinsic and extrinsic pathways end with the activation of factor X to factor Xa.

Factor Xa then combines with factor Va to form the molecule prothrombinase.

Prothrombinase will then go on to convert prothrombin to thrombin.

Front 22

What is prothrombinase? What is it composed of?

Back 22

Prothrombinase is the enzyme that converts prothrombin to thrombin.

It is composed of factors Xa and Va.

Front 23

Describe the intrinsic pathway of the coagulation cascade.

Back 23

XII activated XIIa

XIIa activates XI to XIa

XIa activates IV to IVa

IVa activates X to Xa

Front 24

Describe the extrinsic pathway of the coagulation cascade.

Back 24

Exposure to tissue factor results in activation of VII to VIIa.

VIIa activates X to Xa.

Front 25

Which branch of the coagulation cascade is activated by tissue factor?

Back 25

Extrinsic pathway

Front 26

What do the Roman numerals in the names of clotting factors indicate?

Back 26

The order in which they were discovered and NOT the order in which they are activated

Front 27

Which branch of the coagulation cascade takes longer to complete?

Back 27

Intrinsic pathway

Front 28

Which electrolyte is also considered a clotting factor?

Which clotting factor is it?

Which branch of the coagulation cascade is it necessary for?

Back 28

Calcium

Calcium is factor IV

Required for both intrinsic and extrinsic pathways

Front 29

What is factor I?

Back 29

Fibrinogen

Front 30

What is factor II?

Back 30

Prothrombin

Front 31

What is factor III?

Back 31

Tissue factor

Front 32

What is factor IV?

Back 32

Calcium ions

Front 33

What type of molecules are the coagulation factors?

Back 33

Enzymes

Front 34

What is the role of Vitamin K in clotting?

Back 34

Vitamin K is required for the synthesis of four clotting factors: