9. Transport In Animals

• Circulatory System

  • The circulatory system is a system of blood vessels with a pump and valves to ensure one-way flow of blood

  
• Circulatory system in fish

  Two-chambered heart and single circulation
• Circulatory system in fish


  For every one circuit of the body, the blood passes through the heart once
• Circulatory system in mammals

  Four-chambered heart and double circulation
• Circulatory system in mammals

  For every one circuit of the body, the blood passes through the heart twice
• Circulatory system in mammals

  1. Right side of heart receives deoxygenated blood from body and pumps it to lungs (pulmonary circulation)

  2. Left side of heart receives oxygenated blood from lungs and pumps it to body (systemic circulation)
• Advantages of Double Circulation: Extended

  • Blood travelling through the small capillaries in the lungs loses a lot of pressure that was given to it by the pumping of the heart, meaning it cannot travel as fast
  • By returning the blood to the heart after going through the lungs its pressure can be raised again before sending it to the body, meaning cells can be supplied with the oxygen and glucose they need for respiration faster and more frequently
• The single circulatory system in fish

  
• The double circulatory system in mammals

  
• The Mammalian Heart

  • The heart is labelled as if it was in the chest so what is your left on a diagram is actually the right hand side and vice versa
  • The right side of the heart receives deoxygenated blood from the body and pumps it to the lungs
  • The left side of the heart receives oxygenated blood from the lungs and pumps it to the body
  • Blood is pumped towards the heart in veins and away from the heart in arteries
  • The two sides of the heart are separated by a muscle wall called the septum
  • The heart is made of muscle tissue which are supplied with blood by the coronary arteries
• Monitoring Activity of the Heart

  • Heart activity can be monitored by using an ECG, measuring pulse rate or listening to the sounds of valves closing using a stethoscope
  • Heart rate (and pulse rate) is measured in beats per minute (bpm)
  • To investigate the effects of exercise on heart rate, record the pulse rate at rest for a minute
  • Immediately after they do some exercise, record the pulse rate every minute until it returns to the resting rate
  • This experiment will show that during exercise the heart rate increases and may take several minutes to return to normal
• Structure of the heart

  
• Investigating Effect of Physical Activity on Heart Rate

  1. Measure breathing rate by counting breaths per minute

  2. Measure heart rate by taking a pulse

  3. Measure before and after activity

  4. Plot results on a bar chart

  5. Ensure consistent time and full recovery between activities
• It is relatively simple to investigate the effects of exercise on the body in the classroom
• Increased physical activity

  Increased heart rate and breathing rate
• Physical activity has stopped

  Heart rate remains high for a period of time, then gradually returns to resting heart rate
• Coronary Heart Disease


  A condition where the coronary arteries that supply the heart muscle with blood become partially or completely blocked, reducing blood flow and oxygen supply to the heart
• Heart


  • Made of muscle cells that need their own supply of blood to deliver oxygen, glucose and other nutrients and remove carbon dioxide and other waste products
• Coronary arteries


  Blood vessels that supply the heart muscle with blood
• Coronary artery blockage

  1. Fatty deposits called 'plaques' (mainly formed from cholesterol) build up

  2. Arteries become less elastic and cannot stretch to accommodate blood flow

  3. Restricted blood flow to cardiac muscle cells
• Partial blockage of coronary arteries

  Restricted blood flow to cardiac muscle cells, resulting in severe chest pains called angina
• Complete blockage of coronary arteries


  Cells in that area of the heart cannot respire and can no longer contract, leading to a heart attack
• Diet, Exercise & Coronary Heart DiseaseReducing the risks of developing coronary heart disease

  • Quit smoking
  • Diet - reduce animal fats and eat more fruits and vegetables - this will reduce cholesterol levels in the blood and help with weight loss if overweight
  • Exercise regularly - again, this will help with weight loss, decrease blood pressure and cholesterol levels and help reduce stress
• The coronary arteries

  
• Buildup of plaque in the coronary arteries

  
• Effect of narrowing of arteries

  
• Risk Factors for CHD Table

  
• Ventricles


  • Thicker muscle walls than the atria as they are pumping blood out of the heart and so need to generate a higher pressure
• Left ventricle

  • Thicker muscle wall than the right ventricle as it has to pump blood at high pressure around the entire body, whereas the right ventricle is pumping blood at lower pressure to the lungs
• Septum


  Separates the two sides of the heart and so prevents mixing of oxygenated and deoxygenated blood
• Function of valves


  Prevent blood from flowing backwards
• Sets of valves in the heart

  • Atrioventricular valves
  • Semilunar valves
• Atrioventricular valves


  Separate the atria from the ventricles
• Tricuspid valve


  Valve on the right side of the heart
• Bicuspid valve


  Valve on the left side of the heart
• Function of atrioventricular valves


  1. Pushed open when the atria contract

  2. Pushed shut when the ventricles contract to prevent blood from flowing back into the atria
• Semilunar valves


  Found in the two blood arteries that come out of the top of the heart
• Semilunar valves are the only two arteries in the body that contain valves
• Function of semilunar valves


  1. Open when the ventricles contract so blood squeezes past them out of the heart

  2. Shut to avoid blood flowing back into the heart
• Structure of the heart showing the different valves