THE HEART
In a fish: (single circulatory)
Oxygenated blood is pumped from the heart to the gills.
Where it collects oxygen and becomes oxygenated.
Oxygenated blood now passes straight from the gills to the organs.
When the oxygen diffuses out of the blood and into the body cells,
the blood returns to the heart.
The problem with a single circulatory system is that the blood loses
a lot of pressure as it passes through the gills before reaching the
organs.
This means that the blood passes to the organs relatively slowly so it cannot deliver a great deal of
oxygen.
Unlike fish, humans have a double circulatory system.
In a human: (double circulatory)
Deoxygenated blood is pumped from the heart to the
lungs where it collects oxygen.
This oxygenated blood then returns to the heart. The
heart then returns to the heart.
1. The heart now pumps the oxygenated blood to
the organs where the blood transfers its oxygen to the body cells, and the blood now
returns back to the heart. The benefit of the double circulatory system is up because the
blood passes through the heart twice, it can travel rapidly to the body cells delivering the
oxygen that the cells need.
2. The heart is an organ consisting mainly of muscle tissue.
3. The heart pumps blood around the body.
4. The heart has four chambers.
5. The atria are separated from the ventricles by valves.
6. The Vena cava brings in deoxygenated blood from the body.
7. The blood passes from the heart to the lungs in the pulmonary artery.
8. Oxygenated blood passes from the lungs to the heart in the pulmonary vein.
9. Oxygenated blood is pumped from the heart to the body in the aorta.
10. First blood enters the left atrium and the right atrium.
11. The atria now contract and the blood is forced into the ventricles.
12. The ventricles now contract and force blood out of the heart.
Valves stop the blood from flowing backward into the atria when the ventricles contract.
In a fish: (single circulatory)
Oxygenated blood is pumped from the heart to the gills.
Where it collects oxygen and becomes oxygenated.
Oxygenated blood now passes straight from the gills to the organs.
When the oxygen diffuses out of the blood and into the body cells,
the blood returns to the heart.
The problem with a single circulatory system is that the blood loses
a lot of pressure as it passes through the gills before reaching the
organs.
This means that the blood passes to the organs relatively slowly so it cannot deliver a great deal of
oxygen.
Unlike fish, humans have a double circulatory system.
In a human: (double circulatory)
Deoxygenated blood is pumped from the heart to the
lungs where it collects oxygen.
This oxygenated blood then returns to the heart. The
heart then returns to the heart.
1. The heart now pumps the oxygenated blood to
the organs where the blood transfers its oxygen to the body cells, and the blood now
returns back to the heart. The benefit of the double circulatory system is up because the
blood passes through the heart twice, it can travel rapidly to the body cells delivering the
oxygen that the cells need.
2. The heart is an organ consisting mainly of muscle tissue.
3. The heart pumps blood around the body.
4. The heart has four chambers.
5. The atria are separated from the ventricles by valves.
6. The Vena cava brings in deoxygenated blood from the body.
7. The blood passes from the heart to the lungs in the pulmonary artery.
8. Oxygenated blood passes from the lungs to the heart in the pulmonary vein.
9. Oxygenated blood is pumped from the heart to the body in the aorta.
10. First blood enters the left atrium and the right atrium.
11. The atria now contract and the blood is forced into the ventricles.
12. The ventricles now contract and force blood out of the heart.
Valves stop the blood from flowing backward into the atria when the ventricles contract.
