Question 1

Calcium is required for formation of a blood clot.

Accepted Answer

Calcium is required for the activation of blood clotting factors and ultimately the formation of a blood clot. Without sufficient calcium, the blood clotting process can be impaired.

Question 2

Oxygen and carbon dioxide are poorly soluble in plasma so they require erythrocytes for their transport in blood. Describe how erythrocytes transport these gases.

Accepted Answer

The answer of Oxygen and carbon dioxide are poorly soluble...

Question 3

Carbonic anhydrase is an enzyme in erythrocytes essential for the transport of carbon dioxide as bicarbonate ions.

Accepted Answer

Carbonic anhydrase is an enzyme present in erythrocytes, and it plays a crucial role in the transport of carbon dioxide from tissues to the lungs. It catalyzes the conversion of carbon dioxide and water into carbonic acid, which then quickly dissociates into bicarbonate ions and protons. These bicarbonate ions are transported out of the erythrocytes into plasma, where they are transported by blood to the lungs for elimination.

Question 4

Polycythemia is a decrease in the oxygen- carrying capacity of blood.

Accepted Answer

Polycythemia is actually an increase in the number of red blood cells, which can cause the blood to become thicker and increase the risk of blood clots. This leads to an increase in the oxygen-carrying capacity of blood, not a decrease.

Question 5

Leukocytes are necessary to protect the body against foreign substances, including bacteria and viruses. Describe the different classes of leukocytes and their major functions.

Accepted Answer

The answer of Leukocytes are necessary to protect the body...

Question 6

Anemia is caused by a low hematocrit.

Accepted Answer

The answer of Anemia is caused by a low hematocrit....

Question 7

Glucose is transported in blood dissolved in plasma.

Accepted Answer

Glucose, being a soluble and small molecule, can be transported dissolved in plasma in the blood.

Question 8

Release of ADP by platelets is part of a positive feedback loop for platelet aggregation.

Accepted Answer

ADP released by platelets serves as a signal to recruit more platelets to the site of injury and promote further aggregation, leading to the formation of a stable plug. This is an example of positive feedback, where the end result reinforces the initial action.

Question 9

Following centrifuging of blood, the middle layer contains platelets and leukocytes, and is called the buffy coat.

Accepted Answer

This statement is true.

Question 10

Coagulation factors continuously circulate in the blood in their inactive form.

Accepted Answer

Coagulation factors are present in the blood in their inactive form until they are activated by a trigger such as tissue injury.

Question 11

Iron can be stored in the liver and spleen bound to ferritin.

Accepted Answer

Iron can be stored in the liver and spleen bound to ferritin, a protein that binds and stores iron.

Question 12

Collagen activates factor X.

Accepted Answer

Collagen primarily plays a role in platelet adhesion and aggregation during the initial stages of blood clot formation, but it does not directly activate factor X. Factor X activation is part of the coagulation cascade, typically initiated by tissue factor (Factor III) or contact with negatively charged surfaces in the intrinsic pathway.

Question 13

Vitamin K is necessary for blood clot formation because it activates the extrinsic pathway.

Accepted Answer

Vitamin K is necessary for blood clot formation because it activates proteins in the intrinsic pathway (factors II, VII, IX, and X) and proteins C and S, which are part of the anticoagulation system, rather than specifically activating the extrinsic pathway.

Question 14

In healthy endothelial cells, arachidonic acid is converted to thromboxane A2.

Accepted Answer

In healthy endothelial cells, arachidonic acid is primarily converted to prostacyclin (PGI2), not thromboxane A2, which is produced by platelets.

Question 15

Thrombin is activated by factor X.

Accepted Answer

Thrombin is formed by the coagulation cascade pathway which involves activation of factor X, also known as the Stuart-Prower factor.

Question 16

Blood is composed of fluid components and formed elements (cells). Describe the properties of the fluid and cellular components of blood.

Accepted Answer

The answer of Blood is composed of fluid components and...

Question 17

The formation of platelet plugs and blood clots is an important hemostatic (defined by the elimination of bleeding)function of the blood. However, there are mechanisms within vessel walls that inhibit clot formation and dissolve those clots that have formed. Describe the mechanisms that inhibit clot formation and dissolve clots, including the relevant compounds.

Accepted Answer

The answer of The formation of platelet plugs and blood...

Question 18

Thrombin not only promotes clotting at injury sites, but also indirectly inhibits clotting in healthy tissue.

Accepted Answer

Thrombin activates fibrinogen to form fibrin, which helps to form a clot at an injury site. However, thrombin also activates protein C, which inhibits clotting in healthy tissue by breaking down factors V and VIII. This helps to prevent excessive clotting and maintain blood flow in normal tissue.

Question 19

The ability to prevent blood loss from vessels that have been damaged is an important hemostatic function. Describe in detail the three steps in the process of hemostasis including the compounds involved in those processes.

Accepted Answer

The answer of The ability to prevent blood loss from...

Question 20

Jaundice is caused by an excess of iron in the blood.

Accepted Answer

Jaundice is caused by an excess of bilirubin, a yellow pigment produced when the liver breaks down red blood cells, in the blood. It is not caused by an excess of iron.

Quiz 15: The Cardiovascular System: Blood