Organisation

• What’s a tissue?

  A group of cells with a similar structure and function
• What are organs?

  Aggregations of tissues performing a specific function
• What are cells?

  The building blocks for all living organisms
• How are organs organised?

  Organs are organised into organ system, which work together to form organisms
• What are enzymes?

  Enzymes are biological catalysts, which speeds up the rate of reaction. All enzymes are made of large proteins which all proteins are made up of chains of amino acids.
• What theory models enzyme action?

  Lock and key
• What is the lock and key model?

  The specific substrate fits into the unique active site that binds to catalyse reactions.
• What temperature and pH do enzymes work best at?

  optimum temperature or pH so the enzyme doesn’t denature
• Where is amylase made?

  the salivary glands, the pancreas and the small intestine
• Where is protease made?

  The stomach, the pancreas, the small intestine
• Where is Lipase made?

  The pancreas, the small intestine
• What is carbohydrates broken down into?

  into carbohydrase then into simple sugars
• What is proteins broken down into?

  Into protease then into amino acids
• What is lipids broken down into?

  Into lipase, then into fatty acids and glycerol
• What is bile? Where‘s it made?

  Bile is produced in the liver, it’s stored in the gall bladder. Bile neutralises stomach acid and emulsifies fats - which gives a bigger surface area of fat for the enzyme lipase to work which increases rate of digestion.
• What’s the role of the stomach?

  It pummels the food with its muscular walls, it produces hydrochloric acid to kill bacteria and to give the right pH for the protease enzyme to work - pH 2
• How is the heart a double circulatory system?

  The right ventricle pumps deoxygenated blood to the lungs to take in oxygen, the blood returns to the heart and the left ventricle pumps oxygenated blood to all the other organs - it’s a double circuit
• The heart

  • deoxygenated blood flows into the vena cava and then to the right atrium, through the valves into the right ventricle, through the valves and out of the pulmonary artery to the lungs
  • oxygenated blood returns and flows through the pulmonary vein, to the left atrium, through the valves and into the left ventricle, through the valves and out the aorta to supply blood to the rest of the body
• How is the resting heart rate controlled?

  By a group of cells in the right atrium wall, called the pacemaker. This produces small electric impulses which spreads to the surrounding muscles which helps them to contract.
• What‘s an artificial pacemaker?

  A little device implanted under the skin and has a wire going into the heart - to control the heartbeat if the natural pacemaker cells don’t work properly. It produces an electrical current to keep the heart beating regularly.
• What are the arteries?

  The arteries carry blood away from the heart.

  Adaptions - strong elastic walls (high pressure blood), thick walls, thick layers of muscle to make them strong and elastic fibres to allow them to stretch and spring back.
• What are the capillaries?

  Are involved in the exchange of materials at the tissues.

  Adaptions - permeable walls (diffuse substances in and out), one cell thick walls (increases diffusion by decreasing distance over which it occurs).
• What are the veins?

  Carry blood to the heart.

  Adaptions - bigger lumen (help blood flow), thin walls (blood is at a lower pressure), have valves to prevent back-flow of blood.
• What’s the function of red blood cells?

  To carry oxygen to lungs and all cells in the body.

  Adaptions - biconcave shape (large surface area to absorb oxygen), no nucleus (carry more oxygen).
• What’s the function of white blood cells?

  Defend against infection, produce antibodies to fight microorganisms and antitoxins to neutralise any toxins produced by microorganisms, have a nucleus.
• What’s the function of platelets?

  Helps blood clot; are small fragments of cells, have no nucleus. Help blood clot at a wound to stop all blood from pouring out and stop microorganisms getting in. Lack of platelets can cause excessive bleeding and bruising.
• What’s the function of plasma?

  Plasma is the liquid that carries everything in blood; red blood cells, white blood cells, platelet, nutrients (glucose and amino acids), carbon dioxide from organs to the lungs, urea from the liver to kidney, hormones, proteins, antibodies and antitoxins produced by white blood cells.
• What’s coronary artery disease?

  When the coronary arteries that supply blood to the muscle of the heart gets blocked by layers of fatty material building up. This causes arteries to become narrow, so blood flow is restricted and a lack of blood flow to the heart muscle which can cause a heart attack.
• What are stents?

  Stents are tubes inserted inside arteries. It keeps them open so blood can pass through to the heart muscles - keeping the heart beating.
• What are the advantages of stents?

  Lower the risk of heart attack, they are effective for a long time and recovery time is relatively quick.
• What are the disadvantages of stents?

  There’s a risk of complications, infection from surgery and also a risk of developing a blood clot.
• What are statins?

  Statins are drugs used to lower cholesterol levels which are present in the blood. This slows down the rate of fatty deposits forming.
• What are the advantages of statins?

  Lower cholesterol levels can reduce the risk of strokes, coronary heart disease and heart attacks. Increases the beneficial type of cholesterol in the blood stream which removes the ‘bad’ cholesterol. May prevent other diseases.
• What are the disadvantages of statins?

  They are a long term drug, must be taken regularly. Negative side effects; headaches or can be more serious, e.g. kidney failure, liver damage and memory loss. The effect isn’t instant, takes time for their effect to kick in.
• How can heart valves be replaced?

  Faulty heart valves can be replaced with biological or mechanical valves. Biological valves - can be taken from humans or other mammals.

  Mechanical - man made.
• How can heart valves be damaged?

  By heart attacks, infection or old age.

  This damage may cause valve tissue to stiffen, so won’t work properly. Or a valve may become leaky, allowing blood flow in both directions, which means the blood doesn’t circulate effectively.
• What are problems with replacing a heart valve?

  Blood clots
• What’s an artificial heart?

  A mechanical device that pumps blood for a person whose heart has failed. Normally used as a temporary solution, to keep patient alive until a donor heart can be found.
• What are the advantages of an artificial heart?

  Less likely for rejection because they’re made from metal or plastic so the body doesn't recognise them as ‘foreign’
• What are the disadvantages of an artificial heart?

  Doesn't work as well as natural ones - parts could wear out or the electric motor could fail. Blood doesn’t flow smoothly through the heart - which can cause blood clots which can lead to strokes. The patient needs to take drugs to thin their blood to prevent this from happening which can cause bleeding problems in an accident.