Final answer:
Venoconstriction inhibits venous return by increasing blood pressure within the vein, blood flow within the vein, and the return of blood to the heart. The contraction of the gastrocnemius muscle in the legs and gravity actually enhance venous return. Inspiration and enlargement of the right atrium during contraction of the right ventricle do not directly inhibit venous return.
Step-by-step explanation:
Venoconstriction is the process that inhibits venous return. Venoconstriction increases blood pressure within the vein, blood flow within the vein, and the return of blood to the heart. It improves venous return by reducing the diameter of the veins and increasing the force of blood flow back to the heart.
The contraction of the gastrocnemius muscle in the legs and the force of gravity actually enhance venous return. The contraction of leg muscles, known as the skeletal muscle pump, exerts pressure on the veins and helps move blood back to the heart. Additionally, gravity aids in the movement of blood from the lower extremities to the heart.
In contrast, inspiration and enlargement of the right atrium during contraction of the right ventricle do not directly inhibit venous return.