the heart

• where does deoxygenated blood go to?

  the lungs where gas exchange surfaces take up oxygen
• how does oxygen get into body?

  diffuses into blood from the alveoli
• how does carbon dioxide get out of body?

  diffuses from the blood into the lungs (to be exhaled) via the alveoli
• what type of system is the heart?

  a double circulatory system
• what does the right side of the heart do?

  pump blood to the lungs for gas exchange (this is the pulmonary circuit)
• why is the left side of the heart so thick?

  pumps blood under high pressure to the body (this is the systemic circulation)
• what are benefits of the double circulatory system?

  by returning oxygenated blood to the heart from the lungs, the pressure can be raise before sending it to the body, meaning cells can be supplied with oxygenated blood more quickly.

  • this is important for mammols as they require lots of oxygen to maintain their body temperature.
• the double circulatory system in humans

  A) pulmonary artery

  B) pulmonary vein

  C) lungs

  D) vena cava

  E) aorta

  F) renal vein

  G) renal artery

  
• what type of blood does the right side of the heart recieve?

  it recieves deoxygenated blood from the body and pumps it to the lungs
• what type of blood does the left side of the heart recieve?

  oxygenated blood from the lungd and pumps it to the body
• how is blood pumped towards the heart?

  veins
• how is blood pumped away from the heart?

  arteries
• what are the chambers at the top of the heart called?

  atria
• what are the chambers at the bottom called?

  ventricles
• what is the purpose of valves?

  to prevent blood flowing backwards
• what type of muscle is the heart made of?

  cardiac muscle
• why does the heart never get tired?

  cardiac muscle cells contain far more mitochondria to provide lots of ATP.

  it also has its own blood supply via the coronary arteries which provide a constant oxygen supply
• label the heart!

  A) pulmonary artery

  B) aorta

  C) vena cava

  D) pulmonary vein

  E) right

  F) right

  G) left

  H) left

  
• 1. STEP 1: what does the vena cava do?

  brings in deoxygenated blood from the body, emptying into the right atrium
• 2. STEP 2: where does the blood go after the vena cava brings it into the heart?

  the blood passes from the heart to the lungs in the pulmonary artery.
• STEP 3: where does the deoxygenated blood go after it gets to the lungs?

  it picks up oxygen and then goes back to the heart in the pulmonary vein.
• STEP 4: where does the oxygenated blood go after coming back to the heart?

  pumped to the body through the aorta.
• Pathway of blood through the heart

  • Deoxygenated blood (from the body) enters the heart via the vena cava, emptying into the right atrium
  • Oxygenated blood (from the lungs) returns to the heart via the pulmonary vein, emptying into the left atrium
  • The atria contract pushing the blood into the ventricles 
  • The right ventricle contracts forcing blood through the pulmonary artery to the nearby lungs where the blood becomes oxygenated
  • At the same time the left ventricle contracts forcing the oxygenated blood through the aorta, out of the heart to the body.