Circulatory system

• In fish, where is deoxygenated blood pumped from?

  The heart to the gills - where it collects oxygen and becomes oxygenated
• In fish, where is oxygenated blood transported to?

  Passes straight from the gills and to the organs - where the oxygen diffuses out of the blood and into the body cells. The blood now returns to the heart
• What is the problem with a fish's single circulatory system?

  The blood loses a lot of pressure as it passes through the gills before reaching the organs - meaning the blood travels to the organs relatively slowly and cannot deliver a great amount of oxygen
• Humans have a double circulatory system
• In humans where is deoxygenated blood pumped to?

  It's pumped from the heart and to the lungs - where it collects oxygen. This oxygenated blood then returns to the heart
• In humans, after the oxygenated blood returns to the heart, where is the blood now pumped to?

  The heart pumps the oxygenated blood to the organs where the blood transfers its oxygen to the body cells - the blood now returns back to the heart
• What is the benefit of the double circulatory system?

  Because the blood passes through the heart twice, it can travel rapidly to the body cells, delivering the oxygen that the cells need