circulatory system

• What do multicellular organisms need to move substances within their bodies?

  Transport systems
• What is the main function of the circulatory system?

  To transport substances and differentiate cells in multicellular organisms
• What are the main components of the circulatory system?

  The heart, blood vessels, and blood
• What type of blood does the heart pump to the lungs?

  Deoxygenated blood
• What happens to the blood after it is oxygenated in the lungs?

  It is pumped around all the other organs of the animal
• What is one advantage of mammals having a double circulatory system?

  It allows blood to be pumped at much higher pressure
• Do all mammals have a double circulatory system?

  Yes
• Why is a higher blood flow rate important for mammals?

  Because they use up a lot of oxygen to maintain body temperature
• What are the steps of blood circulation in the heart?

  1. Blood flows into the atria from the vena cava and pulmonary vein.
  2. Atria contract, pushing blood into the ventricles.
  3. Ventricles contract, forcing blood into the pulmonary artery and aorta.
  4. Blood flows to organs through arteries and returns through veins.
  5. Atria fill again, and the cycle starts over.
• What type of muscle makes up the heart?

  Cardiac muscle
• Why do cardiac muscle cells contain many mitochondria?

  To provide the cells with ATP
• How is blood supplied to the heart?

  By two coronary arteries
• What are the three main types of blood vessels?

  Arteries, veins, and capillaries
• What is the function of arteries?

  To carry blood away from the heart
• Why are the walls of arteries thick and elastic?

  To withstand high pressure from pumped blood
• What do arteries divide into?

  Arterioles
• What are capillaries?

  The smallest blood vessels, only one cell thick
• What does the human heart need a good blood supply for?

  To remove carbon dioxide produced during respiration
• What prevents backflow of blood in the heart?

  Valves
• How does the heart ensure blood flows in the right direction?

  By using valves that open and close during contractions