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| Frage | Antworten |
| B5 | Circulatory Systems and the Cardiac Cycle |
| Why do some animals, such as amoeba, not need a blood circulatory system? | They rely on diffusion to supply oxygen to all parts of their body. |
| Why would many animals need a blood circulatory system? | Because diffusion alone is not enough for the efficient transfer of materials. |
| What type of circulatory system do insects have? | An open circulatory system. |
| Why do insects have an open circulatory system? | Because insect blood isn't contained in blood vessels; it fills up the body cavity. |
| What type of circulatory system do humans have? | A closed circulatory system. |
| What happens in closed circulatory systems? | Blood is pumped through vessels called arteries, veins and capillaries. |
| What are the features of a single circulatory system? | It has a heart with two chambers. Deoxygenated blood is pumped to the gills, the the oxygenated blood is pumped to the body. Pressure is lower and materials are transported more slowly around the body. |
| What is an example of an animal that has a single circulatory system? |
A fish
Heart > Gills > Body > Heart
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| How many chambers does a double circulatory system heart have? | Four chambers |
| What are the features of a double circulatory system? | The blood returns to the heart for a further pump so that it can go all the way around the body. Blood is under high pressure, so its transported more quickly. |
| What are the features of the chambers in a double circulatory system? | |
| What does the heart need in order to release energy through respiration? | It needs a constant supply of glucose and oxygen. |
| What does the coronary artery do? | It supplies the heart with glucose and oxygen. |
| What does the pulmonary vein do? | It carries oxygenated blood from the lungs to the heart. |
| What does the aorta do? | It carries oxygenated blood from the heart to the rest of the body. |
| What does the vena cava do? | It carries deoxygenated blood from the parts of the body back to the heart. |
| What does the pulmonary artery do? | Carries deoxygenated blood from the heart to the lungs. |
| What happens during each heart beat? | The heart relaxes and blood enters both atria from veins. The atrioventricular valves are open. The atria contract to push blood into the ventricles. The ventricles contract, pushing blood into the arteries. The semilunar valves open to allow this. |
| Who was Galen and what did he believe? | Galen was a Greek doctor who treated gladiators in Rome around 200AD. He believed that blood flowed like a tide between the liver and the heart. |
| What did William Harvey discover? | The the heart pumped blood around the body using blood vessels. Arteries carry blood under high pressure away from the heart. Veins had valves to prevent back flow. |
| What is a pulse? | The pulse is a measure of the heart beat (muscle contraction) to put the blood under pressure. |
| What is the heart beat controlled by? | The heart beat is controlled by groups of cells called the pacemaker. |
| How do the pacemaker cells work? | They produce small electrical impulses, which spread across the heart muscle, stimulating it to contract. |
| During exercise, why do your muscles demand more energy? | Muscles demand more energy so the heart rate speeds up to supply oxygen and glucose to respiring muscles more efficiently. |
| What do you do if the pacemaker fails? | Its common to have an artificial pacemaker transplanted into the chest and wired to the heart to keep the heart beat regular. |
| What does the sinoatrial node (SAN) do? | It produces impulses that spread across the atria to make them contract. |
| What does the atrioventricular node (AVN) do? | It relays impulses that spread over the ventricles to make them contract. |
| How can nerves regulate the heart beat? | Nerves connecting the heart to the brain can increase or decrease the pace of the SAN. |
| What hormones also alter the heart rate? | Adrenaline. |
| What are the two methods are used to monitor the heart? | An electrocardiogram (ECG)- monitors the electrical impulses from the heart. An echocardiogram- uses ultrasound to produce an image of a beating heart. |
| B5 | Running Repairs |
| Why does an irregular heartbeat occur? | If the pacemaker becomes faulty |
| Why could blood be allowed to flow backwards and reduce blood pressure? | If the cuspid and semilunar valves become weak or damaged. |
| What causes a coronary heart attack or heart disease? | When the coronary arteries become blocked by fat and cholesterol, reducing blood flow to the heart. |
| What is bypass surgery? | It uses blood vessels from the leg to replace the blocked arteries. |
| What is the consequence of being born with a hole in the heart? | It means that blood can move from the right side to the left, so oxygenated and deoxygenated blood can mix, resulting in less oxygen in the blood. |
| What are the features of the heart of a foetus? | It is normal to have a hole in a foetus heart as they receive oxygen from the mother through the placenta, so they don't need a double circulatory system. |
| How can a severely damaged heart be fixed? | It can be replaced by a donor heart. |
| Name three advantages of of pacemakers and heart valves. | There is no human donor needed. There is less risk of rejection. They involve a much less traumatic operation. |
| What is the disadvantage of pacemakers and heart valves? | They may need replacing. |
| What are the advantages of heart transplants? | The transplanted organ will last for the lifetime of the patient. The patient will feel better immediately and can lead a full life. |
| Name three disadvantages of heart transplants. | Its a major expensive operation. There is a long waiting time for a suitable donor. The patient will need to take immunosuppressants for the rest of their life. |
| Where does blood clot? | Normally, blood clots at cuts to prevent blood loss, but sometimes it clots abnormally inside blood vessels. |
| What happens when you have a cut? | Platelets in the blood gather at the site, forming a clot. A substance called fibrin builds over the wound, which combines with the platelets and plasma to make a scab. |
| What types of drugs can be used to reduce clotting inside blood vessels? | Anticoagulant drugs, such as warfarin, heparin and aspirin. |
| What is haemophilia? | An inherited disease where the blood fails to clot due to a faulty clotting protein. |
| What are the four different blood groups? | A, B, AB and O |
| What are the blood groups determined by? | The A and B markers on the surface of red blood cells. |
| What is another marker of blood type? | Rhesus. There is Rhesus positive and Rhesus negative. |
| How much blood is taken from a donors arm? | 500ml of blood is taken from a vein in their arm. |
| What will happen if the donors blood group is not matched to the recipients? | The donated blood will clump inside the recipient and cause problems. |
| Why do people give blood? | Because they may have had a blood transfusion before and know how important it is. They want to help save lives. Its a quick and simple procedure. |
| What makes red blood cells dump if they come in contact with the corresponding antigen? | Markers called agglutinins. |
| What types of agglutinins do different blood types have? | Blood group A have A-agglutinins and blood group B have B-agglutinins. |
| What is another word for blood clumping? | Aglutination |
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