Biology - B3.2 - Transporting Materials - Revision Cards in GCSE Biology

B3.2.1 - The Circulatory System and the Heart

Large organisms need transport system to move materials around body - humans have a circulatory system: consists of blood vessels, the heart and blood
Heart - muscular organ, pumps blood around bod - actually two pumps held together
Right pump forces deoxygenated blood to lungs: picks up oxygen, loses CO2 -> returns to left pump which pumps oxygenated blood aorund body
Heart has four chambers - upper: atria - receive blood from vena cava (right) and pulmonary vein (left) - atria contract blood to lower: ventricles - force blood in pulmonary artery (right) and aorta (left)
Heart vavles stop blood going wrong way - heart is supplied with oxygenated blood via coronary arteries
Actions of both sides of heart results in double circulation

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Blood flows around body in arteries, veins and capillaries
Arteries: carry blood away from heart, thick wall containing muscle and elastic tissue
Veins: thinner walls than arteries, valves to prevent backflow
Cappilaries: narrow, thin-walled vessels, carry blood through organs and allow exchange of substances with all living cells in body
Heart keeps blood flowing through vessels - if blocked or too narrow: blood won't flow efficiently: organs will be deprived of nutrients and oxygen
Stents - inserted to keep blood vessels open - beneficial when coronary arteries narrow due to fat: cutting off blood to heart
Leaky valves - blood could flow in wrong direction - artificial or animal valves can be inserted in heart to replace damaged valves

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Blood is a tissue - the fluid plasma contains red and white blood cells and platelets
Blood plasma transports: CO2 from organs to lungs, soluable products from digestion from small intestine to organs, urea from liver to kidneys
Red blood cells: biconcave discs that don't have a nucleus, contain red pigment haemoglobin which combines with oxygen forming oxyhaemoglobin in lungs, carry oxygen to organs where oxyhaemoglobin returns to oxygen ans haemoglobin
White blood cells: have nucleus, form part of bodies defence system
Platelets: small fragments of cells, don't have a nucleus, help to clot blood at site of wound

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Blood from donors separated into cells and plasma, must be refridgerated, some can be frozen
Plasma given to patients in transfusion to increase blood volume
Artificial blood, eg. perfluorocarbons (PFCs) can be used - aren't refridgerated, doesn't contain cells: doesn't have to be matched, expensive, doesn't carry as much oxygen, some are insoluable in water: don't mix well with blood, some cause side-effects
Patients who suffer heart failure need new heart - lack of donors: artificial hearts being developed to keep patients alive - don't need to match and don't need immunosuppressant drugs, problems with blood clotting, long stays in hospital, expensive

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Flowering plants have separate transport systems
Xylem tissues - transport water and mineral ions from root to stem, leaves and flowers
Transpiration stream - movement of water from roots through xylem and out of leaves
Phloem tissue - carries dissolved sugars from leaves to rest of plant, including growing regions and storage organs

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