Heart and blood

• The heart is an organ that is mainly made of muscle tissue
• It is divided into four chambers, seperated by valves
• The left side of the heart pumps blood to the body
• The right side of the heart pumps blood to the lungs
• Arteries carry blood away from the heart
• Veins carry blood back into the heart
• The conorary artery suppplies the heart muscle with oxygen and glucose for respiration
• Blood flows through the VenaCava into the right atrium. Then into the right ventricle up out of the Pulmonary Artery. This is deoxygenated blood travelling towards the lungs
• After the blood has been to the lungs it goes into the left atrium via the Pulmonary vein. This then goes into the left ventricle and out of the aorta which then takes oxygenated blood around the body.
• Where does the blood go when leaving the pulmonary artery?


  Lungs, it is deoxygenated
• Where has the blood going in the aorta?


  It is oxygenated and going to the body
• What is the blood like when entering the venecava?


  Deoxygenated
• Where are the pacemaker cells?


  Right atrium
• What do pacemaker cells do?


  Control the resting heart rate
• In arteries blood is at high pressures, this is maintained by the thick, muscular walls. Also by the narrow lumen and elastic fibres
• In capillaries it is the site of exchange so substances like o2 and co2 move in and out of the blood. The wall is only one cell thick so there is a short diffusion pathway
• In veins blood is at a low pressure. They have thinner walls, wider lumen and valves to control the backflow of blood
• The blood is an example of a tissue as it is made up of groups of similar cells
• Red blood cells transport oxygen around the body. They have a biconcave shape, no nucleus and contains haemoglobin
• White blood cells recognise and destroy microbes. They have a larger shape, nucleu and change shape to carry out phagocytosis
• Platelets are cell fragments that cause blood clots. They are made from recycled parts of cells
• Plasma is a liquid that transports cell substances such as co2, glucose and hormones
• Haemoglobin is a red pigment found inside red blood cells that transports oxygen around the body
• Coronary heart disease is reduced blood flow due to more cholesterol meaning heart muscle gets less o2 and glucose. Less energy released reducing muscle activity in the heart so less blood flow around the body
• How can you help coronary heart disease?


  Statins - a drug that lowers cholesterol

  Stent - mesh tube that holds open the artery and restores normal blood flow
• How to solve a faulty heart valve?

  Biological replacement ( from animals)

  Mechanical replacement
• Heart failure is when the heart does not pump blood efficiently around the body
• Faulty heart valve is when the valve doesn't open or close properly, leading to inefficient blood flow
• How to treat heart failure?


  Temporary - mechanical heart (pump takes over the job of the heart)

  Permanent - Heart transplant ( risk of rejection, long waiting lists, patient must take immunosuppressant drugs)
• The lungs are site of gas exchange. They are specialised to allow oxygen to move into the blood and carbon dioxide to move out of the blood
• The diaphragm controls ventilation - air coming in and out
• Alveolus are the site of gas exchange
• Each alveolus is surrounded by capillaries filled with blood
• Alveolus has a large surface area, thin walls, good blood supply and is ventilated
• The blood entering the lungs has very little oxygen and travels in the pulmonary artery
• The blood leaving the lungs has very little carbon doxide and travels in the pulmonary vein