Transport in humans

• Single circulation system


  Transport system that exists in fish, where blood goes through the heart only once in one full circulation
• Double circulation system


  Transport system in mammals, where blood goes to the heart, then to the lungs, and back to the heart again in one full circulation
• Double circulation system


  1. Deoxygenated blood enters right atrium

  2. Pumped to right ventricle

  3. Pumped to lungs via pulmonary artery

  4. Oxygenated blood returns to left atrium

  5. Pumped to left ventricle

  6. Pumped to body via aorta
• Septum


  • Muscular separation between right and left sides of the heart, important for maintaining blood pressure
• Artery


  Blood vessel that takes blood away from the heart
• Vein


  Blood vessel that takes blood to the heart
• Heart valves


  • Flaps that allow one-way transfer of blood between heart chambers, prevent backflow
• Thickness of heart walls

  • Left ventricle wall is thicker than right ventricle, to provide more force to pump blood around the body
• Physical activity


  Increases heart rate to circulate more blood and deliver more oxygen/nutrients, remove more waste
• Coronary artery


  Supplies blood to the heart muscle itself
• Blocked coronary artery


  Leads to coronary heart disease and heart attacks
• Risk factors for coronary heart disease

  • Poor diet with too much saturated fat
  • Smoking
  • Stress
  • Obesity
  • Lack of exercise
  • Inherited factors
• Heart


  Main organ for transportation in humans
• Blood pumping in the heart

  1. Blood enters heart through veins

  2. Blood enters atrium

  3. Blood enters ventricles

  4. Blood exits heart through arteries
• Heart


  • Has top chambers called atrium
  • Has bottom chambers called ventricles
  • Has a double pump and double circulation
• Blood is always red in color, not blue
• Deoxygenated blood


  Goes to lungs to get oxygenated
• Oxygenated blood


  Goes from heart to cells
• Tissue fluid/Lymph


  Fluid that oozes out from blood capillaries and stays in between tissues
• Lymphatic system


  • Sucks up lymph fluid and puts it back into the circulatory system
  • Has lymph nodes that check for unwanted stuff
• Left ventricle has thicker muscular walls than right ventricle
• Xylem


  Transports water and minerals, one-way upward flow
• Phloem


  Transports food, bi-directional flow up and down
• Xylem


  • Contains tracheids and vessels
  • Passive transport driven by transpiration
• Phloem


  • Contains sieve tubes and companion cells
  • Active transport using ATP
• Transport System


  Transports nutrients and oxygen to organs/cells, removes waste products efficiently
• Diffusion alone is not enough, we need a transport system
• Blood


  Circulatory fluid that transports plasma (90% water, 10% proteins and dissolved substances) and cellular elements (red blood cells, white blood cells, platelets)
• Red blood cells


  • Circular and biconcave with thinner centre, allows them to squeeze through narrow capillaries
  • Lack nucleus to contain more haemoglobin
  • Short 3 month lifespan, replaced by bone marrow
• White blood cells


  • Have a nucleus, can squeeze through capillary walls to reach sites of infection
  • Carry out phagocytosis to remove bacteria and damaged cells
  • Produce antibodies to deactivate specific antigens
• Inflammatory response


  1. Injured cells release chemicals

  2. Nearby blood vessels leak fluid, causing swelling

  3. Dilutes toxins, brings oxygen, platelets and clotting proteins

  4. Attracts phagocytes to engulf bacteria
• Platelets


  • Smallest blood cells, 250,000-400,000 per mm3
  • Live 5-8 days before destroyed by phagocytes
  • Used for blood clot formation, highly adhesive
• Blood clot formation


  1. Thromboplastin from damaged tissue reacts with calcium and prothrombin

  2. Prothrombin converted to thrombin

  3. Thrombin converts fibrinogen to insoluble fibrin threads

  4. Mesh of fibrin threads solidifies, top layer dies forming scab
• Arteries


  • Thick, elastic muscular walls to withstand high blood pressure
  • Do not contain valves
• Veins


  • Relatively thin, less muscular walls
  • Contain valves to prevent backflow
• Blood pressure differences across blood vessels

  Highest in arteries, lowest in veins
• Formation of tissue fluid

  1. Tissue cells bathed in interstitial fluid

  2. Dissolved substances diffuse between blood capillaries and tissue fluid

  3. Oxygen, nutrients diffuse out of capillaries into tissue fluid and cells

  4. Waste products diffuse from cells into tissue fluid and capillaries
• Blood groups


  A, B, AB, O
• Exchange of substances between blood and interstitial fluid

  1. Tissue cells are bathed in tissue fluid (interstitial fluid)

  2. Tissue fluid allows the diffusion of dissolved substances between the tissue cells and the blood capillaries

  3. Dissolved food substances and oxygen diffuse out from the blood capillaries into the tissue fluid then into the cells

  4. Excretory products diffuse out from the cells into the tissue fluid and then through the capillary walls into the blood
• Types of Blood Group

  • A
  • B
  • AB
  • O