Anticoagulants: Chapter 13 Quiz

What is the action of factor X?

Factor X activates the conversion of prothrombin to thrombin in the common pathway of blood clotting.

Would the drug interfere with the intrinsic or extrinsic clotting pathway?

The drug would interfere with the common (or final) pathway of blood clotting.

Distinguish between the systemic and the pulmonary circulation.

Systemic circulation carries oxygenated blood from the heart to the body, while pulmonary circulation carries deoxygenated blood from the heart to the lungs for oxygenation.

Describe the structure of the heart and its components.

The heart is divided into four chambers: two atria and two ventricles. The atria receive blood from the venous system, while the ventricles pump blood into the arterial system. Signup and view all the answers

Explain the meaning of intrinsic and extrinsic as applied to the clotting pathways. How do the two pathways differ from each other? Which steps are common to both?

The intrinsic pathway is activated by damage inside the blood vessel, while the extrinsic pathway is activated by external trauma. The two pathways differ in the factors that initiate them. The common steps to both pathways include the final common pathway where factor X activates the conversion of prothrombin to thrombin. Signup and view all the answers

What is the function of sodium citrate and ethylenediaminetetraacetic acid (EDTA) in preventing blood clotting in test tubes?

They chelate (bind to) calcium, lowering Ca21 levels in the blood to inhibit clotting. Signup and view all the answers

How does heparin prevent blood clotting?

Heparin activates antithrombin III, a plasma protein that combines with and inactivates thrombin. Signup and view all the answers

What is the mechanism of action of warfarin (coumadin) as an anticoagulant?

Warfarin inhibits the cellular activation of vitamin K by inhibiting the enzyme vitamin K epoxide reductase. Signup and view all the answers

Why is warfarin the only clinically used oral anticoagulant?

Warfarin is the only clinically used oral anticoagulant because it blocks the cellular activation of vitamin K, which is essential for blood clotting. Signup and view all the answers

What is the role of vitamin K in blood clotting?

Vitamin K is required for the conversion of glutamate into gamma-carboxyglutamate, which is needed for proper function of clotting factors II, VII, IX, and X. Signup and view all the answers

What is the mechanism by which heparin prevents blood clotting?

Heparin activates antithrombin III, a plasma protein that combines with and inactivates thrombin. Signup and view all the answers

How does warfarin (coumadin) serve as an anticoagulant?

Warfarin blocks the cellular activation of vitamin K by inhibiting the enzyme vitamin K epoxide reductase, which is required for blood clotting. Signup and view all the answers

What are the functions of sodium citrate and ethylenediaminetetraacetic acid (EDTA) in preventing blood clotting in test tubes?

Both sodium citrate and EDTA chelate (bind to) calcium, lowering the Ca21 levels in the blood that can participate in the clotting sequence, thus inhibiting clotting. Signup and view all the answers

Why must warfarin be given to a patient for several days before it becomes effective as an anticoagulant?

Warfarin must be given for several days because it interferes with the production of clotting factors II, VII, IX, and X, which takes time to deplete. Signup and view all the answers

What is the role of vitamin K in blood clotting and how does warfarin affect this role?

Vitamin K is required for the conversion of glutamate to gamma-carboxyglutamate, which is more effective at bonding to Ca21 and is needed for the proper function of clotting factors. Warfarin inhibits the activation of vitamin K, thereby serving as an anticoagulant. Signup and view all the answers

What are the different types of formed elements of the blood and how do they differ in terms of their origin, appearance, and function?

The different types of formed elements of the blood are erythrocytes, leukocytes, and platelets. Erythrocytes are produced in the bone marrow, appear as biconcave discs, and function to carry oxygen. Leukocytes are also produced in the bone marrow, have a larger and irregular shape, and function in immune response. Platelets are cell fragments derived from megakaryocytes, appear as small, irregularly shaped bodies, and function in blood clotting. Signup and view all the answers

How is the rate of erythropoiesis regulated?

The rate of erythropoiesis is regulated by the hormone erythropoietin, which is produced mainly by the kidneys in response to low oxygen levels in the blood. Signup and view all the answers

What is meant by 'type A positive' in the context of blood transfusion, and what can happen if the donor and recipient are not properly matched?

Type A positive refers to the blood type that has A antigens and Rh factor present on the surface of red blood cells. If the donor and recipient are not properly matched, the recipient's immune system may attack the donor's blood cells, leading to a transfusion reaction. Signup and view all the answers

Explain the structure of the heart and its components, highlighting the function of the atria and ventricles.

The heart is divided into four chambers: two atria and two ventricles. The atria receive blood from the venous system, while the ventricles pump blood into the arterial system. The atria and ventricles are separated by a muscular wall, and the atria and ventricles have distinct myocardial cell bundles, structurally and functionally separated from each other. Signup and view all the answers

Explain the difference between the systemic and pulmonary circulations, and the role of each in the circulation of blood.

The systemic circulation carries oxygenated blood from the heart to the body's tissues and returns deoxygenated blood back to the heart. The pulmonary circulation transports deoxygenated blood from the heart to the lungs, where it becomes oxygenated, and then returns oxygenated blood back to the heart. Signup and view all the answers