Study Question Fourteen

• Q14. List 2 factors that contribute to the forward movement of blood in the arterial blood vessels and describe the factors that aid the movement of blood back to the heart through the veins.
• Factors Contributing to Movement of Blood in Arteries:

  • Heart's Pumping Action (Systolic Pressure)
  • Elasticity and Recoil of Arterial Walls
  • Vessel Diameter and Smooth Muscle Contraction (Vasoconstriction)
• • Heart's Pumping Action - Systolic Pressure
  • Heart generates pressure during contraction (systole), pushing blood into arteries. This is the primary force driving blood forward through arterial system.
• • Elasticity and Recoil of Arterial Walls
  • Walls of arteries are made of elastic tissue. After the heart contracts and forces blood into arteries, the walls stretch. When the heart relaxes (diastole), the elastic walls recoil, helping to propel blood forward and maintain a steady flow.
• • Vessel Diameter and Smooth Muscle Contraction - Vasoconstriction
  • Smooth muscle in arterial walls can constrict (vasoconstriction) or relax (vasodilation), affecting diameter of arteries. When arteries constrict, they increase pressure and aid the forward flow of blood, while dilation helps regulate blood distribution based on need.
• Factors Contributing to Movement of Blood in Veins:

  • Skeletal Muscle Pump
  • Respiratory Pump
  • Valves in Veins
  • Venoconstriction (Smooth Muscle Contraction)
• • Skeletal Muscle Pump
  • As muscles contract and relax during movement, they compress veins, and push blood toward the heart. Valves in veins prevent backflow, ensuring blood moves in the right direction.
• • Respiratory Pump
  • Breathing important in venous return. During inhalation, diaphragm moves downward, creating negative pressure in thoracic cavity and increasing pressure in abdominal cavity. Pressure difference helps draw blood toward the heart from lower parts of body.
• • Valves in Veins
  • Veins contain valves that prevent backflow of blood, ensuring it moves towards heart, especially against gravity. Valves are essential for maintaining venous return, particularly in lower extremities.
• • Venoconstriction - Smooth Muscle Contraction
  • Smooth muscle in walls of veins can constrict (venoconstriction), increasing pressure and helping push blood toward heart, particularly during physical activity or stress.
• List factors that contribute to the forward movement of blood in the arterial blood vessels . . .

  One of the ways blood in the arteries move forward is due to systolic pressure which is when the heart generates pressure during contraction, effectively pushing the blood into arteries. Another method of movement is due to the elasticity of arteries which stretch and recoil during systole and diastole, propelling blood forward. Finally, there is smooth muscle within the walls of arteries either vasoconstrict or vasodilate, changing the diameter of the vessel to manipulate the pressure or flow.
• . . . describe the factors that aid the movement of blood back to the heart through the veins.

  One of the ways veins move blood forward is through the skeletal muscle pump, which relies on the contraction and movement of skeletal muscles to compress veins which push blood toward the heart. Another pump is the respiratory pump, this pump relies on breathing and the movement of the diaphragm during inhalation to create pressure which would draw the blood towards the heart.
• . . . describe the factors that aid the movement of blood back to the heart through the veins.

  A third factor is the presence of valves in veins, which prevent the backflow or regurgitation of blood, keeping the flow moving towards the direction of the heart. Finally, similar to arteries, there is constriction known as venoconstriction. Venoconstriction is smooth muscle contraction which add pressure and pushes blood toward the heart.