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CHAPTER 2BLOOD CIRCULATION AND TRANSPORT SYSTEM2.1 TRANSPORT SYSTEM IN HUMANBlood circulatory systemHuman blood circulatory system consist of heart, blood and blood vesselsThe function of the blood circulatory system are to:Transport oxygen and nutrients to all body cellsTransport waste products (carbon dioxide and urea) for eliminationTransport chemicals such as hormones and antibodiesHuman have a closed blood circulatory system.Blood flows in closed blood vessels and the exchange of substances like gas and food takes place through the walls of the capillaries.Blood is carries to the heart by specific blood vessels and pumped out from the heart through different blood vesselsThe blood vessels that carries blood out of the heart is called arteryAorta is the largest artery in the bodyThe blood vessels that carries blood into the heart is called veinVena cava is the largest vein in the bodyIn the vein, blood is prevented from back flowing by valve

Structure of the heart and its function

The heart is a muscular organ which contracts and relaxes continuously to pump and circulate blood to the whole bodyThe heart situated in the thoracic cavity between the left lung and the right lungThe heart has 4 chambers:Left atrium (also known as left auricle)Right atrium (also known as right auricle)Left ventricleRight ventricleThe atriums are situated at the upper part of the heart, while the ventricles are situated at the lower part of the heartAtrium is smaller than ventricleThe wall of ventricles are thicker and stronger than atriumThe wall of left ventricle is thicker and more muscular compared to that of the right ventricleThis is because stronger pressure is needed by the left ventricle to pump blood to whole bodyTYPES OF BLOOD VESSELSFUNCTIONVena cavaChannels deoxygenated blood from all parts of the body to right atriumPulmonary arteryCarries deoxygenated blood from the heart to the lungsPulmonary veinCarries oxygenated blood from the lung to the heartAorta Carries oxygenated blood from the heart to the whole bodyPARTS OF THE HEARTBlood CIRCULATION THROUGH THE HEARTVena cava carries deoxygenated blood from all parts of the body to the right atriumWhen the right atrium is filled with blood, the wall of right atrium will contract and push the blood through tricuspid valveWhen the right ventricle is filled with blood, it will contract and push the blood through semilunar valve into the pulmonary arteryGaseous exchange takes place in the humanCarbon dioxide diffuses out and oxygen diffuses into the bloodOxygenated blood then flows from the lungs into the left atrium through the pulmonary veinThe left atrium will contract and pushes blood through the bicuspid valve into the left ventricleThe contraction of the left ventricle wall pushes blood to the semilunar valve into the aortaThe aorta then carries the blood to the whole bodyFlow chart of the blood circulation:

Blood VESSELS IN HUMANBlood vessels are tubes in the body that channel blood3 types of blood vessel in the human bodyArteryVeinBlood capillaryComparison between artery, vein and blood capillaryARTERYVEINBLOOD CAPILLARYSTRUCTUREFUNCTIONCarries blood out of the heartCarries blood to the heartCarries blood from the artery to the vein

ARTERYVEINBLOOD CAPILLARYTYPE OF BLOOD CARRIEDOxygenated blood (except pulmonary artery)Deoxygenated blood (except pulmonary vein)Carries oxygenated blood from artery to body cellCarries deoxygenated blood from body cells to the veinRATE OF BLOOD FLOWHigh pressured bloodLow pressured bloodBlood flows very slowlyARTERYVEINBLOOD CAPILLARYTHICKNESS OF BLOOD VESSEL WALLThick, muscular, strong and elastic wallThin, less muscular and less elastic wallPorous and thin wallLUMEN SIZEsmallbigVery smallEXISTENCE OF VALVENoYesNoComparison between oxygenated and deoxygenated bloodOXYGENATED BLOODDIFFERENCEDEOXYGENATED BLOODHighOXYGEN CONCENTRATIONLowLowCARBON DIOXIDE CONCENTRATIONHighHighTHE CONCENTRATION OF DIGESTED FOODVery lowNot presentWASTE PRODUCTSPresentArtery and pulmonary veinBLOOD VESSEL THAT CARRIES ITVein and pulmonary arteryBright redBLOOD COLOURDark redBlood circulationHuman have a double blood circulatory systemPulmonary circulationSystemic circulationPulmonary circulation consist of blood vessels that transport blood from the heart to the lungs and back to the heartSystemic circulation consists of blood vessels involved in the blood circulation from the heart to all parts of the body (except lung) and back to the heartLungsBody cells

Pulmonary CirculationSystemic CirculationIMPORTANCE IN MAINTAINING A HEALTHY HEARTHeart disease is caused by:Damage to the valve in the heartFailure of the ventricle and atrium muscular walls to contractBlockage of blood supply to the heart as a result of cholesterol depositsBalanced food intake, exercise and low work pressure are beneficial for a healthy heartThe importance of maintaining a healthy heart:Avoid contracting heart diseaseEnsure that our body cells get enough supply of oxygen and food2.2 HUMAN BLOODCONTENTS OF BLOOD AND THEIR FUNCTIONBlood consists of:PlasmaRed blood cellsWhite blood cellsPlatelets Blood consists of:PlasmaThe liquid part of the bloodYellowish in colour and alkaline characteristicsPlasma contains dissolved substances like mineral salts, digested food, waste products, vitamins, hormones, antibodies and gasesRed blood cells, white blood cells and platelets float in plasmaProduced in the liverRed Blood CellsBiconcave shapeDo not have nucleusFunction: transport oxygen to body cellsProduce in the bone marrowWhite Blood CellsLarger size than red blood cell and dont have definite shapeHave a nucleusFunction: protect the body from being attacked by microorganismsProduced in bone marrow and lymph glandsPlateletPlatelets are small pieces in the blood that have no definite shapeDo not have nucleusThe size of platelet are very smallFunction: to clot blood in a wound to prevent the loss of an excessive amount of bloodProduced in the bone marrow

BLOOD GROUPHuman blood is classified into 4 groups:ABABOA person who donates his blood to another is called blood donorA person who receives blood from another is called a recipientBlood transfusion is the transfer of blood from a donor to a recipientThe blood of the recipient and the donor must be compatibleIf incompatible, blood clotting (agglutination) will occur, and can cause death to the recipientBlood transfusion that can be done between donor and recipientRECIPIENTDONORBLOOD GROUPA BABOABABOPeople with blood group AB are called universal recipients because they can receive blood from people with blood group O, A, B and AB.People with blood group O are called universal donor because they can donate blood to people with blood group O, A, B and ABBLOOD donationThe loss of a lot of blood as a result of an accident or an operation needs to be replaced with blood transfused from another personThis is because massive blood loss will damage bodily functions and cause deathPeople are encouraged to donate blood to save the lives of othersBlood transfusion must be carried out with care to avoid blood coagulationThe type of blood transfused to a recipient must be suitable and compatibleTwo types of blood transfusion:Through blood kept in the blood bankThrough direct channelling from donor and recipientBlood donation is important because there is no substitute for blood

STORAGE AND HANDLING OF BLOODEach blood donor must be tested beforehand to know his or her blood groupThe donor must also be examined by a doctor to ensure that the donors body is healthy enough for blood transfusionBefore blood is transfused to a patient, it must be tested to ensure that it is free from diseases like hepatitis B, hepatitis C, HIV and venereal diseases like syphilisBlood obtained from a donor should be stored in a cold place before use2.3 TRANSPORT SYSTEM IN PLANTSTRANSPIRATIONTranspiration process in plants in which is lost in the form of water vapour through evaporation from the surface of leavesIf too much water evaporates from a plant, the cells of the plant will lose turgid pressure and wiltStomata are pores or openings on the surface of leavesMore stomata are found on the under surface of leavesThe pore size of the stomata is controlled by the guard cellsFunction of stomata:Allows air to diffuse in and out of the leavesEnables water vapour to be released from the leaves during transpirationThe structure of stomata:

FACTORS AFFECTING THE RATE OF TRANSPIRATIONFactors affecting the rate of transpiration are:TemperatureLight intensityWindAir humidity

Please refer to SPS Book for experiment (page 22)THE IMPORTANCE OF TRANSPIRATION TO A PLANTThe role of transpiration is to:Get rid of excess water from plantsCool the plants on the hot daysTransport water and mineral salts from the roots to the whole plantTRANSPORT IN PLANTS THROUGH THE XYLEM AND PHLOEMXylem is a vessel which transports water and mineral salts from the roots to the leavesXylem is situated in the middle sectionPhloem is a vessel which transports food (glucose) from the leaves to the stems and rootsPhloem is located in the bark of the plant