Biology - B3.2 - Transporting Materials

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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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B3.2.2 - Keeping the Blood Flowing

  • 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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B3.2.3 - Transport in the Blood

  • 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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B3.2.4 - Artificial or Real

  • 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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B3.2.5 - Transport Systems in Plants

  • 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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