PE: Paper 1 AQA A Level PE

• What is venous return?


  The return of blood back to the right side of the heart via the vena cava
• Why are mechanisms needed to maintain venous return?


  The pressure of the blood in large veins is very low which makes it difficult to get blood back to the heart
• What are the mechanisms needed to maintain venous return?


  Skeletal muscle pump, respiratory pump, pocket valves, smooth muscle in veins, heart
• What is the skeletal muscle pump?


  When muscles contract and relax, they press on veins squeezing blood back to the heart
• What is the respiratory pump?


  When muscles contract and relax during breathing, pressure changes occur in the chest cavity which compress nearby veins squeezing blood back to the heart
• What are pocket valves?


  Valves in veins keep the blood flowing in one direction and close to prevent backflow
• What does the smooth muscles in veins do?

  Squeeze the blood back to the heart
• How does the heart help to maintain venous return?


  The heart acts as a suction pump when it contracts and relaxes
• What is the impact of blood pressure on venous return?


  When the systolic blood pressure increases, there is an increase in venous return and vice versa
• What is the equation for blood pressure?

  Blood flow x resistance
• What is blood pressure?

  The force exerted against the vessel wall
• What is systolic pressure?


  The pressure in the arteries when the ventricles contract
• What is diastolic pressure?


  The pressure in the arteries when the ventricles relax
• Where is blood pressure measured?

  At the brachial artery in the upper arm
• What is a typical blood pressure reading at rest?

  120/80 mmHg
• What is blood pressure dependent on?

  The type of blood vessel and the distance from the heart
• What is the blood pressure in arteries?

  High
• What is the blood pressure in arterioles?

  Medium
• What is the blood pressure in capillaries?

  Low
• What is the blood pressure in the venules?

  Low
• What is the blood pressure in the veins?

  Low
• What is the total area of arteries?

  Low
• What is the total area of arterioles?

  Medium
• What is the total area of capillaries?

  High
• What is the total area of venules?

  Medium
• What is the total area of veins?

  Low
• What are the two types of circulation?

  Pulmonary and systemic
• What is pulmonary circulation?


  Deoxygenated blood from the heart to the lungs and oxygenated blood back to the heart
• What is systemic circulation?


  Oxygenated blood to the body from the heart and then the return of the deoxygenated blood from the body to the heart
• What are the blood vessels in order?

  Heart, arteries, arterioles, capillaries, venules, veins, heart
• What type of walls do arteries have?

  Thick elastic walls. Have a smooth muscle layer
• What is the lumen of an artery like?

  Small lumen
• What pressure and velocity do arteries carry blood under?

  High pressure and high velocity
• Where do arteries carry blood?

  Away from the heart
• Does an artery contain valves?

  No
• What are the walls of veins like?


  Thinner less elastic walls with less smooth muscle than arteries
• What is the lumen of veins like?

  Large lumen
• What pressure and velocity do veins carry blood under?

  Low pressure and medium velocity
• Where do veins carry blood?


  Back to the heart
• What do veins contain?


  Non return valves