Circulatory System

• The circulatory system is a system of blood vessels with a pump and valves to ensure one-way flow of blood
• Circulatory system

  A) oxygenated

  B) deoxygenated

  C) lungs

  D) pulmonary artery

  E) right

  F) atrium and ventricle

  G) vena cava

  H) pulmonary vein

  I) left

  J) atrium and ventricle

  K) aorta

  L) pulmonary

  M) systemic

  N) capillary bed

  O) body tissues

  P) non-lungs tissues

  
• • Fish have a two-chambered heart and a single circulation
  • This means that for every one circuit of the body, the blood passes through the heart once
• The single circulatory system in fish

  A) gill capillaries

  B) body capillaries

  C) heart

  D) gill capillaries

  E) artery

  F) ventricle

  G) atrium

  H) two chambered heart

  I) vein

  J) systemic capillaries

  K) body

  L) gill circulation

  M) systemic circulation (body)

  N) oxygenated

  O) deoxygenated

  
• Mammals have a four-chambered heart and a double circulation

  • This means that for every one circuit of the body, the blood passes through the heart twice
• The right side of the heart receives deoxygenated blood from the body and pumps it to the lungs (the pulmonary circulation)
• The left side of the heart receives oxygenated blood from the lungs and pumps it to the body (the systemic circulation)
• Advantages of Double Circulation

  • Blood travelling through the small capillaries in the lungs loses a lot of pressure that was given to it by the pumping of the heart, meaning it cannot travel as fast
  • By returning the blood to the heart after going through the lungs its pressure can be raised again before sending it to the body, meaning cells can be supplied with the oxygen and glucose they need for respiration faster and more frequently
• Single circulatory system - blood flows through the heart once for each circuit of the body

  • slow rate of delivery
  • simple
  • blood pessure reduced as blood passes through the gill capillaries - slows down flow to the rest of the body
  • slower rate of delivery of O2 and nutrients to cells and removal of waste
• Single circulatory system

  A) gill capillaries

  B) artery

  C) heart

  D) ventricle

  E) atrium

  F) 2 chambers

  G) vein

  H) systemic capillaries

  
• Double circulatory system - when the blood goes through the heart twice for each circuit of the body (1)

  • maintains body temperature
  • pumps rapidly and higher pressure
  • system has two separate circuits - one circuit carries blood to the lungs to pick up ozygen, the other circuit carries the oxygen and nutrients around the body to the tissues
• Double circulatory system - when the blood goes through the heart twice for each circuit of the body (2)

  • the oxygenated blood can be pumped rapidly and at a higher pressure to the body - important to maintain body temperature through respiration
  • delivers and removes materials to and from cells rapidly
  • the blood pressure must not be too high in the pulmonary circulation, otherwise it may damage the delicate capillaries in the lung
• Double circulatory system

  A) lung capillaries

  B) pulmonary circuit

  C) atrium

  D) ventricle

  E) atrium

  F) ventricle

  G) right

  H) left

  I) systemic circuit

  J) systemic capillaries

  K) one circuit to lungs

  L) allows for pressure changes

  M) 4 chambers

  N) one circuit to capillaries

  
• The blood (transport medium) carries nutrients and water into the cells and carries carbon out of the cells back into environment

  • cannot rely on diffusion because too slow so we need circulatory system
• What is needed for a good transport system:

  • medium aka blood to carry things
  • blood vessels to carry blood
  • valves to stop backflow
  • heart aka pump for pressure to push the fluid around
  • exchange surfaces to let substances to enter the blood and leave it again where they are needed