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Cell biology
Biological molecules
Organisation
Infection and response
Energy transfers (a2 only)
Homeostasis and response
Responding to change (a2 only)
The control of gene expression (a-level only)
Substance exchange
Bioenergetics
Genetic information & variation
Inheritance, variation and evolution
Genetics & ecosystems (a2 only)
Ecology
Cells
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1c the tudors: england, 1485-1603
1l the quest for political stability: germany, 1871-1991
Inter-war germany
1f industrialisation and the people: britain, c1783-1885
Britain & the wider world: 1745 -1901
2n revolution and dictatorship: russia, 1917-1953
2j america: a nation divided, c1845-1877
The cold war
World war two & the holocaust
World war one
Medieval period: 1066 -1509
The fight for female suffrage
2m wars and welfare: britain in transition, 1906-1957
2d religious conflict and the church in england, c1529-c1570
Britain: 1509 -1745
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01/05/2023
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the circulatory system: @aleyahafsa the circulatory system includes the heart, blood vessels and blood. the heart: Vena Cava Pulmonary valve Right atrium Right ventricle Inferior vena cava there are four chambers of the heart: 1. right atrium 2. right ventricle 3. left atrium 4. left ventricle the heart pumps blood around the body through: 1. pulmonary artery: carries deoxygenated blood from heart to lungs 2. pulmonary vein: carries oxygenated blood from lungs to heart 3. aorta: carries oxygenated blood from heart to body 4. vena cava: carries deoxygenated blood from body to heart Aorta Pulmonary artery Pulmonary vein Left atrium Left ventricle Septum Descending aorta LUNGS HEART 643 C deoxygenated blood BODY W oxygenated blood On each side of the heart, the atrium and ventricle are separated by a valve, which prevents the blood from flowing backwards. pacemaker cells: produce small electrical impulses which spread to the muscular walls of the heart, causing them to contract. if these cells don't work, doctors implant an artificial pacemaker to replace it journey of blood around the body: body tissues → vena cava → right atrium → right ventricle → pulmonary artery →lungs → pulmonary vein → left atrium → left ventricle → aorta → body tissues journey of blood from ventricles and atria: The walls of the atria contract, pushing blood into the relaxed ventricles. The walls of the ventricles contract, pushing blood out of the heart. At the same time, more blood will enter the now-relaxed atria. The cycle repeats. The coronary arteries supply the...
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heart muscle with oxygen and nutrients. blood vessels: there are 3 types of blood vessels: 1. arteries: carry blood away from the heart 2. capillaries: exchange materials at the tissues 3. veins: carry blood towards the heart arteries: ARTERIES capillaries: veins: BLOOD VESSELS blood is pumped at a high pressure so the walls are strong and elastic walls are thicker than lumen (hole in between) thick layers of muscle and elastic fibres CAPILLARIES VEINS permeable so substances can diffuse only 1cm thick - increase rate of diffusion as it has less distance supply food and o2 and take waste like co2 lower rate of blood flow 2. white blood cells 3. platelets 4. blood plasma blood is pumped at a low pressure so walks are not as thick big lumens and thin walls to help blood flow valves - ensure blood doesn't flow backwards blood: there are four types of things in the blood: 1. red blood cells red blood cells white blood cells adaptations: red blood cells: role: transport o2 from lungs to rest of body. platelets white blood cells: role: defend body against pathogens methods: large surface area to volume ratio to increase rate of diffusion has a biconcave disc shape so o2 can fit nicely has haemoglobin. when it combines with o2 it becomes oxyhaemoglobin no nucleus - more space small and flexible - easily pass through the capillaries phagocytosis- process which a white blood cell binds to, and then engulfs a pathogen, in order to destroy it. antibodies- bind to pathogens and help immune cell destroy the pathogens. they have a nucleus platelets: role: clot the blood when a blood vessel breaks importance: Prevents blood from leaving the blood vessels Prevents pathogens from entering the blood has no nucleus as platelets are only fragments of cells plasma blood plasma: role: carry substances and cells around the body carries: replacing blood: Lost blood can be replaced in two ways: 1. artificial blood red blood cells, white blood cells, and platelets nutrients: glucose, amino acids, fatty acids and glycerol waste: co2 and urea hormones and antibodies 2. real blood in a blood transfusion artificial blood: salt water solution replaces the volume of liquid that is lost so your heart can continue to pump blood around the body no red blood cells, so can't carry o2 blood transfusion: contains real blood with red blood cells not readily available