CB8 - Exchange & Transport in Animals

• What is metabolism?

  Metabolism are all the chemical processes that occur within a living organism
• Metabolism produces waste which is excreted through systems around the body.
• The main function of the circulatory system is to transport substances throughout the body, including oxygen from the lungs to cells and carbon dioxide away from cells back to the lungs.
• Waste products such as urea (from protein breakdown) and lactic acid (from muscle contraction) are carried in the blood to the kidneys for removal from the body.
• What is the main form of excretion used by the body?

  Diffusion
• What are the adaptations of the surfaces in which diffusion occur?

  1. are thin - particles do not need to diffuse very far
  2. have a large surface area - more room for particles to diffuse
• What system transport blood through all the body?

  The capillaries in the circulatory system.
• How is the lung adapted to increate its surface area?

  The lung has millions of alveoli, increasing the surface area and the speed and amount of gas exchange.
• How are capillaries adapted to their function?

  Capillaries have one cell thick walls, which eases diffusion of gases, blood and nutrients.
• How does diffusion apply in this circumstance?

  Diffusion is used in the alveoli for quick gas exchange. The oxygen in the alveoli quickly defuses to the capillaries (due to their small walls) and the carbon dioxide waste is moved to the alveoli to be excreted.

  
• In the circulatory system, what carries blood away from the heart?

  Arteries
• What carries blood back to the heart?

  Veins
• Why do arteries have thick walls?

  To withstand the high blood pressure of the blood pumped away from the heart.
• What does the high blood pressure cause on arteries?

  High pressure from the blood causes the arteries to stretch - this is what we perceive as a pulse, when arteries stretch when blood is squirted from the heart onto it.
• What are the purpose of valves?

  Valves make sure that blood only flows in one direction in the veins.
• What blood vessel has valves?

  Veins
• What are the contents of each cubic millimetre of blood?

  1. erythrocytes (red blood cells)
  2. white blood cells
  3. platelets
  4. plasma
• What are the two types of white blood cells?

  Lymphocytes, responsible for the production of antibodies and phagocytes, which digest foreign cells.
• What do lymphocytes do?

  They produce antibodies against pathogens in the body.
• What do phagocytes do?

  They surround and digest foreign cells.
• Which cell has haemoglobin?

  Red Blood Cell
• What is the purpose of haemoglobin?

  Transport oxygen by binding the molecules in the lungs to the red blood cell before being released again in the tissues.
• Explain how a red blood cell is adapted to its function:

  1. They are shaped like a biconcave disk which increases their surface area, meaning they can absorb and release more oxygen efficiently
  2. No nucleus allows for more storage of oxygen
  3. Haemoglobin: binds with oxygen in the lungs and transport it to tissues, then absorbs carbon dioxide and transports it to the lungs to be exhaled
  4. High flexibility allows them to squeeze through tiny blood vessels and reach more tissues in the body, helping to deliver high amounts of oxygen at critical moments such as high intensity workouts.
• Where does most of the blood from the body enter the heart?

  Right atrium through the vena cava
• How many vena cavas are there?

  Two, one superior to transport blood from the superior parts of the body to the heart and one inferior to transport blood from the lower parts of the body.
• Where does blood from the lungs enter on the heart?

  Left atrium
• Which blood vessel brings blood from the lungs to the heart?

  Pulmonary vein
• Describe the blood pumping process in the heart:

  Blood in brought from the vena cava(s) and the pulmonary vein to the right and left atriums. When the atriums are full, the muscles around them contract to push blood into the ventricles. The muscles in the ventricle walls then contract, forcing blood out of the heart through the arteries (pulmonary artery to the lung, and aorta)
• What does the aorta do?

  Returns blood to the rest of the body from the heart.
• What is the purpose of heart valves?

  They ensure blood flows in the right direction - they produce the sound (tu-dum) that we hear from the heart.
• What is does dark red blood mean?

  Deoxygenated blood
• What does light red blood mean?

  Oxygenated blood
• What is cardiac output?The amount of blood pushed into the aorta each minute calculated this equation: $cardiac\space output =$$stroke\space volume\space \times\space heart \space rate$
• What is cellular respiration?

  Chemical reactions that release energy from glucose.
• What type of reaction is respiration?

  Exothermic reaction
• What is the equation for aerobic respiration?

  oxygen + glucose => carbon dioxide + water
• What is the equation for anaerobic respiration?

  Glucose -> Lactic Acid
• Where, in the cell, does anaerobic respiration happen?

  Cytoplasm