2Transport1.1 Understanding the importance of having a transport system in some multicellular organisms
31.1 Understanding the importance of having a transport system in some multicellular organisms Organisms that are small in size have a large total surface area to volume (TSA/V) ratio.Large organisms have a small TSA/V ratio.Hence, the rate of diffusion is higher in small size organisms than the large ones.
41.1 Understanding the importance of having a transport system in some multicellular organisms (cont’d) Unicellular organisms my obtain their nutrients and oxygen by diffusion alone but multicellular organisms are more complex and bigger in size.Thus, they need a special transport system to transport the nutrients and oxygen to the body cells.The transport system in humans and animals are called the circulatory system.The transport system in plants are the vascular tissue which consists of xylem and phloem tissues.
61.2 The concept of circulatory system The circulatory system in humans and animals consists of blood, blood vessels and heart.Blood is the connective tissue in liquid form.The human blood is made up of 55% plasma and 45% blood cells.
111.2 The concept of circulatory system (cont’d) PlasmaConstituentsMajor functionsWaterSolvent for transporting dissolved substances such as glucoseIonsMaintain osmotic balance in the blodd and pH of the blood at 7.4Plasma proteinsAlbuminFibrinogenImmunoglobulinsMaintain osmotic balance, and act as buffers against pH changes.Fibrinogen is involved in the clotting of the blood.Immunoglobulins are antibodies that help in the body’s defence.HormonesControl physiological activities of the bodyDissolved substancesNutrients that are essential for the body
121.2 The concept of circulatory system (cont’d) Erythrocyte (red blood cells)Biconcave disc-shaped : to increase TSA/V ratio to facilitate the gas diffusionProduced in bone marrowLifespan = 120 daysDestroyed in spleen and liverContains haemoglobin; oxygen-carrying protein pigment
131.2 The concept of circulatory system (cont’d) Leucocyte (white blood cells)Colourless, have nucleus (do not contain haemoglobin)Functions ; fight infectionsCan be divided into 2 groups;Granulocytes (granular cytoplasm)Agranular
141.2 The concept of circulatory system (cont’d) GranulocytesNeutrophilsEosinophilsBasophilsCarry out phagocytosis to engulf and digest bacteriaRegulate allergic responsesProduce heparin which prevent blood from clotting too quickly
151.2 The concept of circulatory system (cont’d) AgranulocytesLymphocytesMonocytesFound in lymph system, produce antibodiesPhagocytes
161.2 The concept of circulatory system (cont’d) PlateletsFragments in bone marrowInvolved in blood-clotting
171.2 The concept of circulatory system (cont’d) Blood vesselsArteries – carries blood away from the heartVein – carries blood back to the heartCappillaries
18ArteryCapillaryVeinLocated deeper in the bodyBetween arteriole and venuleLocated near skin surfaceThick muscular wallThin wall, one-cell thickThin wall, less muscularSmall lumenVery small lumenBig lumenNo valves (except pulmonary artery)No valvesValve is present (except pulmonary vein)Blood flow very fast, at high pressureBlood flows is slow, at pressure decreasesBlood flow is slow, at low pressure
191.2 The concept of circulatory system (cont’d) The human heartRefer to figure 1.7, textbook pg. 9
20Contains four chambers Right atriumLeft atriumRight ventricleLeft ventricleMuscular wall on the left ventricle is thickerTo pump blood to the whole body
21Valves are present to prevent backflow of the blood. Tricuspid valveBicuspid valveSemi-lunar valve
221.2 The concept of circulatory system (cont’d) Blood is propelled through the whole body by forced produced from the pumping of the heart and contraction of skeletal muscle.The heart is made of strong cardiac muscle.Cardiac muscleInterconnected, allow signals to be conducted rapidlyMyogenic, contract spontaneously without nervous stimulation
231.2 The concept of circulatory system (cont’d) Contraction of the heart is controlled by sinoatrial node (SA node) a.k.a pacemaker.Impulse from SA node move to atrioventricular node (AV node).Then, it moves through bundle of His fibres, bundle branches and Purkinje fibres.
25SA Node generate electrical impulse. The electrical impulse spread rapidly over atria, causing atria to contractElectrical impulse reach AV node, the pass to the ventricles, causing it to contract simultaneously.The whole atria and ventricles relax and the pressure in the heart is lowered.Blood moves into both atrium.
261.2 The concept of circulatory system (cont’d) Skeletal muscle are usually located around the veins.Contraction and relaxation of the muscles enables the blood to flowValves ensure the blood to flow in one direction
271.2 The concept of circulatory system (cont’d) Blood pressure is the pressure exerted by the blood on the walls of the blood vessels.Normal blood pressure is 120/80 mmHg.120 mmHg = systolic pressure80 mmHg = diastolic pressureBlood pressure is regulated by baroreceptors (pressure receptors) in aorta and carotid arteries.
29Blood pressure regulation Heartbeat rate decreaseCardiac musclesBrainDiameter of arteries increaseSmooth muscles of arteriesNormal blood pressureBaroreceptorsHeartbeat rate increaseCardiac musclesBrainDiameter of arteries decreaseSmooth muscles of arteries
301.2 The concept of circulatory system (cont’d) OpenInsects (open circulatory system)ClosedSingleFishDouble(Amphibians)Incomplete(Human)Complete
311.2 The concept of circulatory system (cont’d) Open circulatory systemHaemolymph is pumped into cavity around the cellsInsects have a tube-shaped heart called ostia.Materials are exchanged between haemolymph and bode cells through diffusion.
32Closed circulatory system Blood is confined in one vesselOne or more hearts pumped blood into major vessels that branches into smaller vessels
331.2 The concept of circulatory system (cont’d) Single closed circulatory systemBlood flows into the heart only onceBlood is pumped by the heart to the gills, body tissues and back to heart again.The heart of a fish is simple; only one atrium and one ventricle.
341.2 The concept of circulatory system (cont’d) Double -closed incomplete circulatory systemBlood flows into the heart twice.Heart has two atrium and one ventricle.The oxygenated blood and deoxygenated blood is mixed in the undivided ventricle.
351.2 The concept of circulatory system (cont’d) Double -closed complete circulatory systemBlood flows into the heart twice.Heart has two atrium and two ventricle.Made up of two main circulationPulmonary circulationDeoxygenated blood is pumped into the pulmonary arteriesSystemic circulationBlood is pumped to the whole body
371.3 The Mechanism of Blood Clotting Importance of blood-clottingTo prevent blood lossTo prevent the entry of microorganisms and foreign particles into the bodyTo maintain blood pressureTo maintain the circulation of blood in a closed circulatory system
461.3 The Mechanism of Blood Clotting Blood-clotting related problemsHaemophiliaProlonged bleeding – will cause blood lossThrombosisFormation of blood clot inside the blood vesselsVenous thrombosis – blood clots in the veinsArterial thrombosis – blood clots in the arteriesArteriosclerosis – arteries becomes narrow due to the deposits of cholesterol and fats, then the artery is hardened by calcium deposits.
491.4 The Lymphatic System Interstitial Fluid Blood arrives at the capillary with high hydrostatic pressureForce some of the plasma to pass across the thin-membrane to fill the space between cell. This will form interstitial fluid.Contains water, dissolved nutrients, hormones, waste products, gases, small proteins.
501.4 The Lymphatic System (cont’d) 90 % of the interstitial fluid diffuses back into the blood capillaries10 % of the interstitial fluid diffuse into the lymph capillaries of the lymphatic system.
511.4 The Lymphatic System (cont’d) Lymphatic system consist of :Lymphatic capillariesFine, blind end lymphatic vesselsLymph vesselsCarries lymphLymph nodesFound along lymph vesselsProduce lymphocytes – provide antibodyPhagocytes are present – ingest bacteria, dead leucocytes, foreign particles
521.4 The Lymphatic System (cont’d) Lymph flow to two main lymphatic vessels;Thoracic ductWill enter the circulatory system via the left subclavian veinRight lymphatic duct
551.4 The Lymphatic System (cont’d) The flow of lymph is aided by a few factors such as:Contraction of smooth muscles in the wall of lymphatic nodesContraction of skeletal muscles when body movesPeristalsis movement in the alimentary canalBreathing movementThe pulses in blood vessels
561.4 The Lymphatic System (cont’d) The role of the lymphatic systemCollect the interstitial fluid and return in into the circulatory systemDefend the body against disease by producing lymphocytesTransport lipid, glycerol and fat soluble vitamin A, D, E dan KTransport water, hormones, glucose, amino acids, minerals and heat in the interstitial fluidTransport waste products such as carbon dioxide and nitrogenous compounds in the interstitial fluids
571.4 The Lymphatic System (cont’d) Comparison among the blood, interstitial fluid and lymph.ContentBloodInterstitial fluidLymphWaterSmall molecules like glucose, amino acids and mineralsLarge molecules like erythrocytes, platelets and plasma proteinLymphocytes
58Transport1.5 The Role of Circulatory System in Body Defence Mechanism
591.5 Body Defence Mechanism Human are exposed to disease-causing microorganisms called pathogens.Body defence mechanism are need toPrevent the entry of pathogenReact with pathogen that enters the bodyThree lines of defence system:First line of defence – skin and mucous membraneSecond line of defence - phagocytesThird line of defence - lymphocytes
601.5 Body Defence Mechanism (cont’d) First line of defenceConsists of skin and mucous membraneSkinOuter layer consists of keratin – physical barrier against microorganismsSebaceous gland – secrets sebum that forms a protective layerSebum is a mild antiseptic – prevent growth of microorganismsSweat – can destroy microorganismsMucous membraneSecretes mucus to protect epithelial tissues
611.5 Body Defence Mechanism (cont’d) Second line of defenceInvolves phagocytes e.g neutrophills and monocytesPhagocytosisPhagocytes approach the pathogen (bacteria) – surrounds it by using its pseudopodiumPhagocytes then engulf the bacteria – forming a phagocytic vacuole called phagosomeLysosome release enzyme, then digest the pathogen
631.5 Body Defence Mechanism (cont’d) Third line of defenceImmune systemInvolves the production of antibodies by lymphocytesAntigens – foreign substances produced by microorganisms, pathogens, toxinAntibody – protein to react with antigenSpecific – one type of antibody can only react with one type of antigen
641.5 Body Defence Mechanism (cont’d) Antigen is destroyed by different mechanismsAgglutination – clump pathogen together for phagocytosisNeutralisation – neutralize toxinOpsonisation – mark antigens for phagocytesLysis – cause antigens to rupture or disintegrate
651.5 Body Defence Mechanism (cont’d) Immunity – ability of the body to resist and infection by producing antibodiesWhen a person has immunity towards certain disease, he/she is said to be immuned to the disease.Immunisation – process of acquiring an immunityTwo types of immunity :Active immunityPassive immunity
661.5 Body Defence Mechanism (cont’d) Active immunity - body acquired immunity when the body produces antibodies against pathogen and antigen.Passive immunity – body acquired immunity when the body receives antibodies from external sourcesBoth active and passive immunities can be acquired naturally or artificially.
671.5 Body Defence Mechanism (cont’d) ImmunityActiveNaturalArtificialPassiveAcquired after recovering from a diseaseAcquired by injection of vaccineAcquired from mother via the placenta and breast milkAcquired by injecting serum containing antibodies