the heart

• The right atrium receives deoxygenated blood from the vena cava.
• when you exercise your body needs more energy, so you respire more. You need to get more oxygen into the cells and remove more carbon dioxide. For this to happen the blood has to flow faster, so your heart rate increases.
• 1.) Exercise increases amount of carbon dioxide in blood

  2.) High levels of blood carbon dioxide are detected by receptors in the aorta and carotid artery

  3.) These receptors send signals to the brain

  4.) The brain sends signals to the heart, causing it to contract more frequently and with more force
• Risk factors for coronary heart disease :

  • Diets high in saturated fats - fatty deposits can from inside arteries
  • Smoking - increases blood pressure which can cause damage to the inside of coronary arteries. The damage makes fatty deposits more likely to form.
  • Being inactive - can lead to higher blood pressure which can also increases chance of fatty deposits forming - narrowing the arteries.
• the right atrium receives deoxygenated blood from the body through the vena cava
• the right ventricle pumps deoxygenated blood to the lungs via the pulmonary artery
• the left atrium receives oxygenated blood from the lungs via the pulmonary vein
• the left ventricle pumps the oxygenated blood around the whole body via the aorta
• valves prevent the backflow of blood into the ventricles