Vascular System

• What is the vascular system primarily composed of?

  A dense network of blood vessels
• What is the primary function of the vascular system?

  To transport oxygen, carbon dioxide, and essential nutrients throughout the body
• What are the main types of blood vessels in the vascular system?

  • Arteries
  • Veins
  • Arterioles
  • Capillaries
  • Venules
• What is the function of arteries in the vascular system?

  To transport oxygenated blood from the heart
• What is the largest artery in the body?

  The aorta
• From which part of the heart does the aorta receive blood?

  From the left ventricle
• What is the function of veins in the vascular system?

  To carry deoxygenated blood back towards the heart
• What is the largest vein in the body?

  The vena cava
• Where does the vena cava deliver deoxygenated blood?

  Back to the right atrium of the heart
• What are arterioles and their function?

  Smaller arteries with a large layer of smooth muscle that can alter lumen diameter
• What is the structure of capillaries?

  They are vessels with a single layer of cells
• What is the primary function of capillaries?

  To allow for gas, nutrient, and waste exchange
• What are venules?

  Smaller blood vessels carrying deoxygenated blood back towards the heart
• What is the overall function of the vascular system?

  • Transports oxygen
  • Carries carbon dioxide
  • Distributes essential nutrients
  • Facilitates waste removal
• What are pocket valves in the veins?

  One way valves that prevent the backflow of blood.
• How does the muscular pump aid venous return?

  The contraction of skeletal muscle compresses the veins, forcing blood back to the heart.
• What role does the respiratory pump play in venous return?

  It creates a pressure difference between the thoracic and abdominal cavities during breathing, squeezing blood back to the heart.
• What is venomotor tone?

  It is the maintenance of pressure in the veins created by the venoconstriction of smooth muscle.
• What are pocket valves in the veins?

  One-way valves that prevent the backflow of blood.
• How does smooth muscle contribute to venous return?

  Smooth muscle in the walls of veins venoconstricts to maintain pressure and help transport blood back to the heart.
• How does the muscular pump aid venous return?

  The contraction of skeletal muscle compresses the veins, forcing blood back towards the heart.
• How does gravity assist in venous return?

  It helps blood from above the heart return towards the heart.
• What role does the respiratory pump play in venous return?

  It creates a pressure difference between the thoracic and abdominal cavities during breathing, squeezing blood back towards the heart.
• What are the main mechanisms of venous return?

  • Pocket valves: prevent backflow of blood.
  • Muscular pump: skeletal muscle contraction compresses veins.
  • Respiratory pump: pressure difference during breathing squeezes blood.
  • Smooth muscle: venoconstriction maintains vein pressure.
  • Gravity: assists blood return from above the heart.
• What is venomotor tone?

  The state of venoconstriction in the smooth muscle of veins that maintains pressure and aids blood transport back to the heart.
• How does smooth muscle contribute to venous return?

  It contracts to create venomotor tone, maintaining pressure in the veins and aiding blood transport back to the heart.
• How does gravity assist in venous return?

  It helps blood from above the heart return towards the heart.
• What are the main mechanisms of venous return?

  • Pocket valves: prevent backflow of blood.
  • Muscular pump: skeletal muscle contraction compresses veins.
  • Respiratory pump: pressure difference during breathing aids blood flow.
  • Smooth muscle: venoconstriction maintains vein pressure.
  • Gravity: assists blood return from above the heart.
• What are the two main demands placed on the vascular system when distributing cardiac output?

  The supply of blood to working muscles and vital organs
• What factors influence the supply of blood to working muscles?

  It is dependent on the type of exercise
• What is the process called that redistributes cardiac output during exercise?

  Vascular shunt mechanism
• What happens to blood flow during the vascular shunt mechanism when exercise begins?

  • Vasoconstriction of arterioles and pre-capillary sphincters connected to organs decreases blood flow to organs.
  • Vasodilation of arterioles and pre-capillary sphincters connected to working muscles increases blood flow to working muscles.
• What happens to blood flow during the vascular shunt mechanism when exercise ends?

  • Vasodilation of arterioles and pre-capillary sphincters connected to organs increases blood flow to organs.
  • Vasoconstriction of arterioles and pre-capillary sphincters connected to working muscles decreases blood flow to working muscles.
• What is the approximate cardiac output at rest?

  5 litres per minute
• How much can cardiac output increase during maximal exercise?

  25-40 litres per minute
• What is the purpose of redistributing cardiac output during exercise?

  To supply blood to the working muscles
• What mechanism is responsible for the redistribution of blood during exercise?

  The vascular shunt mechanism
• Where is the vasomotor control centre located?

  In the medulla oblongata
• What type of information does the vasomotor control centre receive from chemoreceptors?

  Information about increases in blood acidity
• What do baroreceptors monitor?

  Pressure changes on arterial walls