Question

question 1 1 pts which two factors promote the return of venous blood to the heart? blood - pumping action of respirations and cardiac output blood - pumping action of respirations and skeletal muscle contractions smooth muscle contractions and cardiac output skeletal muscle contractions and blood - pumping action of smooth muscle contractions

Explanation:

• Blood - pumping action of respirations: During inhalation, the diaphragm contracts and moves downward, increasing the volume of the thoracic cavity. This creates a negative pressure that helps draw blood back to the heart. During exhalation, the pressure changes also assist in venous return.
• Skeletal muscle contractions: When skeletal muscles contract, they squeeze the veins running through them. Since veins have one - way valves, this squeezing action (like a muscular pump) propels blood towards the heart.

Cardiac output is related to the amount of blood pumped out by the heart per minute and is more about the heart's function of distributing blood rather than specifically promoting venous return. Smooth muscle contractions in veins (venoconstriction) can have some role in venous return, but it is not as prominent as the combined effect of respiratory and skeletal muscle - related mechanisms.

Answer:

blood - pumping action of respirations and skeletal muscle contractions