Topic 10

• Topic: Human Transport


  10/02/2022
• Circulatory System


  The circulatory system is the body's motorway for substances to move from one part of the body to others
• Arteries tend to be red in diagrams
• Veins tend to be blue in diagrams and have valves
• Capillaries are too small to be seen without a microscope and are often not explicitly included in diagrams
• Some smaller and single-celled organisms do not need a circulatory system because diffusion is sufficient
• Once organisms have several layers of cells, diffusion is too slow to sustain life, and a circulatory system is required
• Internal heart anatomy

  Right Atrium 2. Left Atrium 3. Right Ventricle 4. Left Ventricle 5. Atrioventricular Valve 6. Atrioventricular Valve 7. Semilunar Valve 8. Septum 9. Superior vena cava 10. Inferior vena cava 11. Pulmonary Artery 12. Aorta 13. Pulmonary Vein
• Blood passes through the heart twice during a complete circuit: heart → lungs → heart → body
• The heart has 4 chambers: 2 atria and 2 ventricles
• Network of tubes at the top of the heart includes veins that carry blood into the heart and arteries that carry blood out of the heart
• Coronary artery over the surface of the heart carries oxygenated blood to the muscles of the heart
• Blood enters the heart from both the pulmonary and systemic circulation
• Components of the heart's network of tubes

  • Veins that carry blood into the heart
  • Arteries that carry blood out of the heart
• Blood entering the heart

  From both the pulmonary and systemic circuits via the atria
• Deoxygenated blood entering the heart


  Goes into the right atrium
• Oxygenated blood entering the heart


  Goes into the left atrium
• Flow of blood from the atria to the ventricles


  Through the atrioventricular valves
• Closure of atrioventricular valves

  After the ventricles fill up to prevent backflow of blood
• Deoxygenated blood leaving the heart


  Leaves the right ventricle and heads towards the lungs
• Oxygenated blood leaving the heart


  Leaves the left ventricle and flows into the aorta, which eventually splits into several different arteries and supplies oxygen to the cells all around our bodies
• Function of semilunar valves


  Prevent blood from flowing back into the ventricles once it has been pumped out
• Right Ventricle

  • Walls are thicker than atria
  • Walls are 2-3X thinner than left ventricle walls
  • Blood only needs to be pumped to pulmonary circuit and lungs are located adjacent to the heart
• Left Ventricle

  • Walls are much thicker than atria
  • Walls are 2-3X thicker than right ventricle walls
  • Blood needs enough pressure to be pumped around the systemic circuit, therefore muscular walls need to be a lot thicker and stronger to overcome natural resistance
• The importance of the septum

  • Separates the two ventricles to ensure oxygenated and deoxygenated bloods do not mix
  • Mixing of the two blood types causes inefficiencies in the system
  • Red blood cells without oxygen being delivered to respiring cells means respiration cannot occur
• Force of contraction of ventricles is primarily responsible for blood pressure
• Atria do not need strong muscular walls - only push blood into ventricles
• Exercise and adrenaline increase heart rate
• The heart can be monitored using an Electrocardiograph (ECG)
• Blocked blood vessels due to too much saturated fat and cholesterol in the diet can lead to cholesterol building up in the arteries, forming plaque which can reduce blood flow to the heart muscle and damage it
• Summary Task: The function of the heart is to pump blood around the body. Blood travels through the heart twice so it is known as a double circulatory system. This system is more efficient because...
• Summary Task: The wall of the left ventricle is thicker than the wall of the right ventricle because...
• The wall of the left ventricle is thicker than the wall of the right ventricle
• The wall of the left ventricle is thicker than the wall of the right ventricle because


  ...
• The function of the heart is to pump blood around the body
• Blood travels through the heart twice so it is known as a double circulatory system
• The double circulatory system is more efficient because


  there is no mixing of oxygenated and deoxygenated blood. This means that blood leaving the heart to travel to the body is rich in only oxygen.
• The pro way to disect a heart is note book, or left and right ventricle
• Learning Objectives

  1. To be able to name the main blood vessels in the human body

  2. To understand the differences in structures and functions of the main blood vessels

  3. Look at vessels associated with the kidneys and the liver
• Key Words

  • Capillaries
  • Vena cava
  • Aorta
  • Pulmonary artery
  • Pulmonary vein
  • Renal artery
  • Renal vein
  • Hepatic Artery
  • Hepatic Vein
  • Hepatic Portal Vein