The Heart

  • Created by: xw.ellie
  • Created on: 09-10-18 19:48
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  • The Heart
    • Structure of the heart
      • deoxy blood through vena cava, into right atrium, through tricuspid valve, right ventricle, through semi-lunar valve and pulmonary artery, to lungs becomes oxy blood, through pulmonary vein, into left atrium, through bicuspid valve, into left ventricle, through semi-lunar valve and aorta to the body then starts again
      • septum is wall of the heart that stops deoxy and oxy blood mixing
        • valves stop the backflow of blood
    • cardiovascular system + exercise
      • during exercise muscles require more oxygen
      • oxy and nutrients carried to muscles through the blood
      • in exercise heart has to work faster and you're heart rate increases
      • The change is a result of adrenaline being released
      • adrenaline is a hormone released by the adrenal gland
      • adrenaline makes the heart beat faster
    • how the heart pumps blood
      • two phases: systole and diastole.
        • the heart filling up and emptying of blood
      • diastole: phase where the heart muscle relaxes and chambers fill up with blood
      • systole: phase where the heart muscle contracts and pumps blood out of the heart
      • blood pressure: the pressure of blood against the walls of the blood vessel
        • typical blood pressure = 120/80
          • 120 represents systole and 80 diastole
    • capillaries
      • one cell thick
      • one end feeds muscles/body/organs with nutrients and oxygen. other end carries carbon dioxide and waste products through the waklls into veins to remove from the body
      • has a low pressure
      • substances pass through walls called 'semi-permeable'
    • veins
      • capillaries feed the veins
      • walls thinner than arteries but muscular and have large lumen
      • bring back deoxy blood from muscles to the heart and work at a low pressure
      • have valves to stop backflow of blood
      • pulsating muscles close to the veins help keep blood moving 'skeletal pump'
    • arteries
      • carry blood away from the heart
      • some have a pulse due to closeness of the heart
      • work under high pressure so walls are thick and flexible
      • normally carry oxy blood except pulmonary artery
      • smaller arteries branch off larger arteries (aorta) so that oxygen gets to all parts of body
      • outer layer is tough and muscular inner lining is muscular and elastic
    • components of blood
      • made up of red blood cells, white blood cells, platelets, plasma
      • bloods job is to transport oxygen around the body and to remove waste products
      • red blood cells
        • look like small discs
        • contain haemoglobin and allows oxygen to join it making oxyhaemoglobin
        • allows transportation of oxygen around the body
        • transports nutrients and waste products
        • made in the bone marrow of long bones
        • in exercise blood gets thicker(viscose) due to water being lost as waste (sweat)
        • also known as erythrocytes
        • red blood cells: high or low count
          • high count
            • people born at high altitude have more red blood cells, this is because there is less oxygen in the air, the cells have to be very efficient at transporting oxygen, athletes from high altitude countries do exceptionally well at endurance events (marathons), athletes from other countries with low altitude may choose to train in high altitude countries to improve their red blood cell count
          • low count
            • known as anaemia which is a lack of red blood cells or haemoglobin in the blood, causes breathlessness and lacking energy,could be caused by lack of iron, therefore people can take iron supplements or eat iron rich foods to create red blood cells, if you lose a lot of blood you can also become and anaemic
      • white blood cells
        • job is to find and destroy pathogens (pathogens cause diseases eg viruses)
        • engulf bacteria or viruses and digest them or they destroy pathogens with chemicals called antibodies
        • keep us healthy

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