Kaplan Nursing Entrance Exam Practice 2025 – Comprehensive Prep

Veins play a critical role in the circulatory system primarily by transporting deoxygenated blood back to the heart. After delivering oxygen and nutrients to tissues throughout the body, blood is returned to the heart through veins. Unlike arteries, which carry oxygen-rich blood away from the heart to the body, veins collect blood that is low in oxygen and high in carbon dioxide and other metabolic wastes.

This process is essential for maintaining proper circulation and ensuring that oxygenated blood can be reintroduced into the body. The structure of veins, with their larger lumens and thinner walls compared to arteries, along with valves that prevent backflow, is specifically adapted for this purpose.

The other choices relate to functions that are not the primary role of veins. The transportation of oxygenated blood is the function of arteries, while blood pressure regulation primarily involves arterial function and the action of the heart. Although hormones do circulate in the bloodstream, their movement is typically facilitated by both arteries and veins, rather than being a primary function of veins themselves. Understanding the specific role of veins helps clarify the overall function of the circulatory system and the critical processes involved in maintaining hemodynamics.