Question 13

Stasis of blood flow contributes to thrombus formation.

Thrombus formation is significantly influenced by stasis of blood flow. When blood flow is slow or stagnant, it increases the likelihood of clot formation due to the accumulation of platelets and clotting factors at the site.

A) Decreased coagulability

Decreased coagulability refers to a reduced ability of the blood to clot, which would actually hinder thrombus formation rather than promote it. This option is incorrect because lower coagulability would lead to a lesser likelihood of thrombus development.

B) Stasis of blood flow

Stasis of blood flow is a critical factor that contributes to thrombus formation. When blood does not circulate effectively, it can lead to the accumulation of clotting elements, thereby facilitating the formation of a thrombus. This option is correct as it directly correlates with the mechanisms that promote clotting.

C) Intact endothelium

An intact endothelium plays a protective role against thrombus formation. The endothelium normally secretes substances that inhibit clotting, thus its intact state reduces the risk of thrombus development. Therefore, this option is incorrect.

D) Decreased red blood cells

Decreased red blood cells can lead to a lower oxygen-carrying capacity and does not directly influence the mechanisms of thrombus formation. While anemia may have systemic effects, it does not specifically contribute to the clotting process and is thus an incorrect option.

Conclusion

Stasis of blood flow is the only option that directly facilitates thrombus formation by allowing for the accumulation of clotting factors. In contrast, decreased coagulability, intact endothelium, and decreased red blood cells do not promote thrombus formation and can actually inhibit it. Therefore, option B is definitively the correct answer.