circulatory system

• red blood cells carry oxygen from the lungs to the tissues, and returns carbon dioxide to the lungs for exhalation
• what is the function of platelets?

  they are responsible for blood clotting, preventing excessive bleeding
• what is the function of the white blood cells?

  they protect the body against infections
• what is the function of the right side of the heart?

  it pumps blood to the lungs, this is for oxygenation
• what is the function of the left side of the heart?

  it pumps oxygenated blood to the body
• what is the function of the valves?

  they prevent the backflow of blood during contraction, ensuring the unidirectional flow of blood
• what is the function of the atria?

  helps to fully 'load' the ventricle, before ejecting blood away from the heart
• what is the function of the pulmonary artery?

  caries deoxygenated blood from the heart to the lungs, in order to be oxygenated
• what is the function of the pulmonary vein?

  it brings oxygenated blood back to the heart, and empties into the left atrium
• what is the function of the aorta?

  carries oxygenated blood away from the heart, to the body
• In cold environments, blood vessels constrict to preserve heat. This can lower blood pressure and slightly decrease heart rate
• in hot environments, blood vessels dilate to release heat, this can lower blood pressure and increase heart rate to maintain adequate circulation
• The sinoatrial node is a specialised group of cells located in the right atrium, intimating the electrical impulse that begins the heart rate
• What is the function of the atrioventricular node?

  delays the electrical signals to allow the ventricles time to fill with blood from the atria
• what is the function of the HIS and purkinje fibres?

  electrical impulses travel from the av node, through these to the ventricles. this causes the ventricles to contract, pumping blood to the lungs and the body
• What is the purpose of atria contraction?

  The electrical signals from the sa node spread across the atria, causing them to contract and push blood into the ventricles
• what is the purpose of ventricular contraction?

  the contraction of ventricles forces blood into the pulmonary arteries and the aorta
• What is the purpose of relaxation?

  After contraction, the heart relaxes, allowing the chambers to refill with blood in preperation for the next beat
• What is the function of the arteries?

  Carry oxygenated blood away from the heart to the body
• what is the structure of arteries?

  thick, muscular walls to withstand high pressure blood flow
• what is the function of the capillaries?

  Where oxygen, nutrient and waste exchange takes place between the blood and the tissue
• what is the structure of the capillaries?

  tiny blood vessels that connect arteries and veins
• What isthe function of the veins?

  Carries deoxygenated blood back to the heart
• what is the structure of the veins.

  Thinner walls and contain valves to prevent backflow