The Nurse Is Reviewing Venous Blood Flow Patterns

The nurse is reviewing venous blood flow patterns. Which of these statements best describes the mechanism(s) by which venous blood returns to the heart?

A) Intraluminal valves ensure unidirectional flow toward the heart.
B) Contracting skeletal muscles milk blood distally toward the veins.
C) High-pressure system of the heart helps facilitate venous return.
D) Increased thoracic pressure and decreased abdominal pressure facilitate venous return to the heart.