Topic 8 - Exchange and transport in animals

• 1. Substance Exchange:

  • All organisms take in needed substances and eliminate waste. Oxygen and carbon dioxide move via diffusion, water through osmosis, and dissolved food molecules in animals also diffuse.

  1. Urea Removal:

  • Waste product urea, produced by animals, diffuses from cells to blood plasma for kidney removal.

  1. Surface Area to Volume Ratio:

  • Efficient substance exchange depends on the organism's surface area to volume ratio (SA : V).
• How do you calculate SA:V ratio?

  Surface area to volume ratio is calculated by dividing the surface area of an object by its volume.
• How are alveoli adapted for gas exchange?

  Large surface area thin walls thin walls allow for rapid diffusion of gases. They are single-cell thick.
• What are the factors affecting the rate of diffusion?

  Distance: Substance needs more time to travel a long distance.

  Concentration gradient: Substances diffuse faster when there is a big difference between the area they are diffusing from.

  Surface area: The more surface there is, the faster the rate of diffusion.
• What is Fick's law?

  rate of diffusion is directly proportional to: surface area * concentration gradient / time.
• What is found in the blood?

  Red blood cells, white blood cells, platelets, and plasma.
• What is the function of the red blood cell?

  Transporting oxygen.
• What is the function of the white blood cells?

  To defend the body against infections and foreign substances (Pathogens). They contain phagocytes and lymphocytes.
• What is the function of the plasma?

  Transporting all of the substances in the blood.
• What is the function of the platelets?

  Blood clotting damaged areas to prevent bleeding and infection.
• What are the 3 main blood vessels?

  Arteries, veins, and capillaries.
• How are arteries adapted to their function?

  Elasticity and muscular walls to withstand high blood pressure.
• How are capillaries adapted to their function?

  Very thin walls that allow the diffusion of substances. They are single-cell thick,
• How are veins adapted to their function?

  Thin walls, large lumen, and valves to block the blood from flowing in the wrong direction.
• How does the heart pump blood around the body?

  1. The right atrium of the heart receives deoxygenated blood from the body through the vena cava.
  2. The deoxygenated blood moves through to the right ventricle, which pumps it to the lungs via the pulmonary artery.
  3. The left atrium receives oxygenated blood from the lungs through the pulmonary vein.
  4. The oxygenated blood then moves through to the left ventricle, which pumps it out around the whole body via the aorta.

  
• The left ventricle contains a thicker muscle so that it will be able to pump blood around the full body.
• What is cellular respiration?

  cellular respiration is an exothermic reaction that occurs continuously in living cells to release energy for metabolic processes, including aerobic and anaerobic respiration.
• What is Anaerobic respiration?


  Respiration without oxygen. It turns glucose into lactic acid + carbon dioxide + ATP. It is not as efficient as aerobic respiration.
• What is Aerobic respiration?

  Process of producing energy from glucose in the presence of oxygen. Glucose + oxygen --> carbon dioxide + water. C6H12O6 + 6O2 --> 6CO2 + 6H2O.
• 1. Choose a small organism, such as maggots or leaves, that you would like to measure the rate of respiration of.
  2. Place 5cm of soda lime into a test tube.
  3. Place gauze on top of the soda lime and add a small amount of the organism being tested on top of this.
  4. Attach a three-way tap, capillary tube, and syringe to the test-tube. Plug the test-tube with a stopper.
  5. Insert a small amount of colored liquid into the capillary tube.
  6. Turn the 3-way tap to allow air to enter the test tube for 5 minutes. After 5 minutes, close the 3-way tap.
  7. Record how far the colored liquid has moved against a scale.
• How do you calculate cardiac output?

  Cardiac output = heart rate x stroke volume.