Chapter 8 Transport in Animals

• Why do multicellular organisms need a transport system?

  Low surface area: volume ratio means and a higher metabolic rate.
• In a single circulatory system, blood only passes through the heart once for each complete circuit of the body.
• In a double circulatory system the blood passes through the heart twice for each complete circuit of the body.
• In fish, the heart pumps blood to the gills to pick up the oxygen, and then on through the rest of the body in a single circuit.
• The right side of the heart

  Blood comes in from the superior and inferior vena cavas into the right atrium. Blood moves from the atrium though the atrioventricular valve into the right ventricle, then into the pulmonary through the semilunar valve and into the lungs.
• A - Superior Vena Cava

  B - Aorta

  C - Right Atrium

  D - Coronary Artery

  E - Righter Ventricle

  F - Inferior Vena Cava

  
• G - Left Ventricle

  H - Pulmonary Veins

  I - Left Atrium

  J - Pulmonary Artery

  
• A - Pulmonary Artery

  B - Superior Vena Cava

  C - Inferior Vena Cava

  D - Right Atrium

  E - Atrioventricular Valve

  F - Right Ventricle

  G - Semi-lunar valve

  
• Oxygenated blood returns to the heart via the pulmonary veins and is pumped around the body by the left side of the heart.
• H - Aorta

  I - Pulmonary Veins

  J - Left Atrium

  K - Atrioventricular Valve

  L - Valve Tendons

  M - Left Ventricle

  N - Semi-lunar Valve

  
• The Right side of the Heart: B/C - D - E - F - G - A

  
• Oder of the Left Side of the Heart: I - J - K - M - N - H

  
• When the ventricles relax, the semilunar valves open allowing blood to flow out of the ventricles.
• What is the advantage to a double circulatory system?

  The heart can give the blood an extra push between the lungs and the rest of the body. This makes the blood travel faster, so oxygen is delivered to tissues more quickly.
• Closed circulatory systems


  The blood is enclosed inside blood vessels.
• Open circulatory system

  Blood flows freely through the body cavity.
• Circulatory system of insects

  The heart is segmented. It contracts in a wave, starting from the back, pumping the blood into a single main artery.

  The artery opens up into the body cavity.

  The blood flows around the insect’s organs, gradually making its way back into the heart segments through a series of valves.
• The circulatory system of an insect does not carry around oxygen - this is done by the tracheal system.
• Arteries carry blood from the heart to the rest of the body. They have thick walls and carry blood at high pressure.
• Veins return blood to the heart. The walls are thinner than those of arteries because they do not need to withstand as much pressure.
• Capillaries connect arteries and veins. Blood moves slowly through them, allowing time for exchange of materials between cells and the bloodstream.
• Valves prevent backward flow of blood in veins.
• Capillaries connect arteries and veins. These tiny tubes allow exchange between the blood and tissues.
• Insects have open circulatory systems where the haemolymph (blood) fills spaces within their bodies called sinuses. This allows it to reach all parts of the body easily.