Chapter 10


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Chapter 10

  7. 7. - By using a cube, we found that the TSA/V ratio of a cube is inversely proportional to its size. Size α 1 tsa/v -The physical implications are : a) smaller living organisms have larger TSA/V ratios. A large TSA/V ratio helps in the efficient gaseous or solutes diffusion b) larger living organisms have very small TSA/V ratios. A small TSA/V ration limits the rate of gaseous or solutes diffusion.
  8. 8. - How to overcome the transport problem? - Organism A : a)unicellular organism b)has very high TSA/V ratio c)has cells where nutrient and oxygen molecules can easily diffuse into the cell and waste products diffuse out of the cells through its entire cell surface A B C
  9. 9. -Organism B : a) multicellular organisms b) has a very low TSA/V ratio c) less surface area per unit cell for diffusion of nutrient and oxygen molecules into its epidermal cells d) impossible for simple diffusion to occur -Organism C : a) same size as organism B b) has transport tube linking to the interior cells c) increasing TSA/V ratio of organism d) tube transport nutrient, oxygen and unwanted waste molecules in and out of cells
  10. 10. CIRCULATORY SYSTEM -Circulatory system transports substances such as nutrients, water and oxygen to the body cells and removes carbon dioxide and other nitrogenous wastes from the body cells. -The circulatory systems of humans and animals consist of 3 components: a) a medium/fluid – required to carry materials around the circulatory system (blood, haemolymph) b) vessels – tubes for the medium to flow through c) pump – heart that help to propel and circulate the medium around the body
  11. 11. HUMAN BLOOD Blood cells Plasma Erythrocytes (red blood cell) Leucocytes (white blood cell) Thrombocytes (platelets) Granulocytes • basophil •Neutrophil •eosinophil Agranulocytes • monocytes •Lymphocytes Fibrinogen Serum
  12. 12. ERYTHROCYTES - 5 million per mm3 of blood -Tiny (8μm), biconcave, disc shape -Do not have nucleus, mitochondria or ribosomes -Full of haemoglobin - made in the bone marrow, live for about 120 days - Destroyed and recycled in the liver
  13. 13. -Adaptations of erythtocytes: a) have no nucleus – provide more space for haemoglobin b) transport oxygen – haemoglobin combine to oxygen and form oxyhaemoglobin c) transport CO2 – haemoglobin combine to CO2 as hydrogen- carbonate d) biconcave, disc shape – increase the TSA/V ratio for optimum gaseous exchange e) small and flexible – can diffuse through narrow capillary walls
  14. 14. LEUCOCYTES Leucocytes in blood -colorless, do not have haemoglobin -Larger than erythrocytes, fewer in number -7000 per mm3 of blood. Raised the number of leucocytes (leucocytosis), decrease the number of leucocytes ( leucopenia) -Irregular shape, have nucleus -Important in body defence mechanisms against disease - divided into 2 basic types : granulocytes and agranulocytes
  15. 15. Granulocytes -Have granular cytoplasm and lobed nucleus. granules Bi-lobed nucleus -Amoeboid movement and engulf bacteria by phagocytosis -Produce in bone marrow -Divide into 3 types: a) Neutrophils – form 70% of total leucocytes - has multi-lobed nucleus - engulf bacteria by phagocytosis b) Eosinophils – 2-4% of total leucocytes - detoxify chemical, reduce inflammation c) Basophils – 1% of leucocytes
  16. 16. Granulocytes Agranulocytes
  17. 17. AGRANULOCYTES Have non-granular cytoplasm, compact nucleus Divide into 2 types a) Monocytes - Largest of the five types of white blood cell - Produce in bone marrow - Consist 5-8% of all leucocytes - Have bean-shaped nucleus - Ingest bacteria by phagocytosis b) Lymphocytes - Has large, rounded nucleus and small amount of non-granular cytoplasm - Large nucleus contain genes for antibody protein production - Produced in lymph glands and lymphatic nodes - Produced antibodies
  18. 18. THROMBOCYTES (PLATELETES) - Are tiny fragments of megakaryocytes (bone marrow cell) found in the bone marrow. - Colourless, irregular shape, no nucleus. - Measures about 2-3µm across. - Made in the bone marrow and last for about 6-7 days. - Have amoeboid movement - Important in blood clotting, repairing damaged tissues and maintain the integrity of blood vessel wall.
  19. 19. PLASMA - Yellowish liquid which the blood cells are suspended. - Consist about 90% water, 10% dissolved substances. - Dissolved substances consist of plasma proteins, dissolved gases, absorbed food molecules, excretory waste products, hormones and salts. - Heat produced by respiration is being absorbed by plasma.
  20. 20. Content Composition Water • 90% of the plasma • As a solvent and transport medium Proteins • Albumins – for viscocity and osmotic balance • Antibodies e.g. globulin – for immunity • Clotting factors such as fibrinogen and prothrombin Dissolved gases • Consist of CO2 and O2 Absorbed food molecules • Consist of glucose, amino acids, fatty acids, vitamins Excretory waste products • Consist of CO2, urea, uric acid, creatinine Hormones • Adrenaline,insulin,glucagon, antidiuretic hormone Salts • Consist of dissolved ionic salts; sodium,potassium, calcium,magnesium Content of blood plasma
  21. 21. FUNCTION OF BLOOD AND HAEMOLYMPH IN TRANSPORT - Functions of blood: a) transport of materials b) defence against diseases
  22. 22. FUNCTIONS OF BLOOD IN TRANSPORT Materials transported Examples Transported in Transported from Transported to Gases Oxygen Haemoglobin in erythrocytes Lungs Respiring cells CO2 Haemoglobin in erythrocytes Respiring cells LungsHydrogen carbonate ions in plasma Absorbed food Amino acids Plasma Intestines Liver and body tissuesGlucose Vitamins
  23. 23. Mineral salts Iron Plasma Intestines Bone marrow Calcium Teeth and bones Iodine Thyroid glands Hormones Insulin Plasma Pancreas Liver Antidiuretic hormone Pituitary gland Kidney Excretory products Urea, uric acid, ammonium salts Plasma Liver Kidney Heat Metabolic heat Whole blood Liver, muscles Whole body
  24. 24. FUNCTION OF HAEMOLYMPH IN TRANSPORT - Haemolymph is the circulatory fluid in the body cavities of insects that have an open circulatory system. - Known as “ insect blood”. - Contains water, amino acids, sugars, salts and white blood cells - Help to transport hormones, nutrients, salts and metabolic wastes around the body. - Does not contain haemoglobin - Does not transport oxygen and CO2 in insects, these gases are transported by the tracheal system.
  25. 25. OPEN AND CLOSED CIRCULATORY SYSTEM a) Open circulatory system - found in insects, crustaceans (prawns) and molluscs (snails). - “blood” pump from heart aorta arteries body cavities. - Haemolymph reach the body cells directly - Haemolymph diffuses between body cells and re-enters the heart through open-ended veins.
  26. 26. b) Closed circulatory system - found in all vertebrates (human, fish) and invertebrates (earthworms). - blood is pump within a vessel and never comes in direct contact with the body cells. - can transport oxygen and other materials faster
  27. 27. THE STRUCTURE OF HUMAN BLOOD VESSELS - The heart is connected to a series of tubes called blood vessels. -The main types of vessels : artery, arterioles, capillary, venule and vein.
  28. 28. ARTERIES -Carry blood away from the heart at high pressure. -Carry blood that is rich in oxygen (except in the pulmonary artery) - have 3 layered walls consisting of: a) endothelium – inner layer, single flatten cell b) smooth muscles and elastic fibres – thick middle layer c) fibrous connective tissue – external layer -Able to transport blood under high pressure due to the strength of the thick elastic fibres -Contract their smooth muscles to decrease the diameter of the lumen, decreasing the volume of blood flow.
  29. 29. - Relax their smooth muscles to increase the diameter of the lumen and increase the volume of blood flow.
  30. 30. ARTERIOLES -Smaller thin walled, branches of the arteries that end in capillaries. - carry blood from arteries to the capillaries. -Constrict and dilate to regulate blood flow and pressure.
  31. 31. CAPILLARIES -Microscopic thin-walled (one-cell thick) blood vessels. -Carry blood from arterioles to venules. -Have diameters of about 7-9μm -Form capillary networks in most of the organs and tissues of the body.
  32. 32. VENULES -Small veins which carry blood from capillaries to the veins. -Have 3 layered wall : inner endothelium, inner layer of muscle and elastic tissue, outer layer of fibrous connective tissue. - Have thinner walls than arterioles.
  33. 33. VEINS -Carry a slower-flowing blood at low pressure towards the heart. -Carry deoxygenated blood (except in pulmonary vein). -Have 3 layered walls, but these layers are thinner and less muscular than those in the arterial wall. So, they collapse when empty. -Have internal valves (semi-lunar valves) to prevent a backflow of blood. - Have skeletal muscle to move the blood more quickly.
  34. 34. Vessels Aspect Artery Capillary Vein Structure of wall 3 layers – endothelium, smooth muscles, fibrous connective tissue Single layer- endothelium 3 layers- endothelium, smooth muscle, fibrous connective tissue Thickness of wall Thick Very thin Thinner than artery Direction of blood flow Away from the heart From arteries to veins Towards the heart Valve Absent Absent Present Oxygenated blood Yes (except pulmonary artery) Arteriole carry oxygenated blood. Venule carry deoxygenated blood Carries deoxygenated blood (except pulmonary vein)
  35. 35. Blood pressure High Decreases from the arteriole to the venule Low
  36. 36. STRUCTURE AND FUNCTION OF THE HUMAN HEART -Enveloped by a membrane called pericardium. - Made up of cardiac muscles -Cardiac muscles are made up of muscle fibres -Each muscle fibre is made up of interconnecting muscle cells. -Muscle cells are joined one to another by intercalary disc that allow the rapid transmission of nervous impulses from cell to cell through the tissue. -Myogenic, it can relax and contract on its own (do not need nerve to stimulate). Contractile cell
  37. 37. Muscle fibre of a heart
  38. 38. -Has 4 chambers : a) 2 upper auricles / atria b) 2 lower ventricles -A thick muscular wall, called medium septum completely separate the right side of the heart from its left side. -The heart functions as 2 separate pumps side by side: (a) The right side of the heart pumps deoxygenated blood (b) The left side of the heart pumps oxygenated blood
  39. 39. -Contraction of the atria: (a) when the right atrium contracts, blood passes into the lower right ventricle. (b) when the left atrium contracts, blood passes into the lower left ventricle. -Contraction of the ventricle: (a) when the right ventricle contracts, it pumps blood out into the pulmonary arteries. (b) when the left ventricle contracts, it pumps blood out into the aorta
  40. 40. -Thickness of the muscular walls: (a) Atria have thinner and less muscular walls because they only pump blood down the ventricles. (b) Right ventricle has to pump blood to the lungs, and therefore has a thick wall. (c) Left ventricles has to pump blood to the body and has thickest wall. -Has 4 valves : (a) Tricuspid valve  on the right side of the heart  has 3 flaps  prevents the backflow of blood into the right atrium when the right ventricle contracts. (b) Bicuspid valve/ mitral valve  on the left side and has 2 flaps  prevents the backflow of blood into the left atrium when the left ventricles contracts. Tricuspid valve Bicuspid valve Aorta Pulmonary artery
  41. 41. (c) Semi-lunar valves  found at the base of pulmonary artery and aorta  prevent the backflow of blood into the right and the left ventricles when they relax.
  42. 42. Bicuspid valve (3D) Upper part – tricuspid valve Lower part – bicuspid valve
  44. 44. THE CIRCULATION OF BLOOD IN HUMAN -Humans have closed, double circulatory system: a) It is closed because the blood is contained within the heart and the blood vessels, does not come in direct contact with the respiring body cells. b) It is double circulatory system because the blood passes through the heart twice for each complete circuit of the body. -Consist of 2 sub-circuits: (a) Pulmonary circulation – heart lung heart (b) Systemic circulation – heart rest of the body heart
  45. 45. Pulmonary circulation Systemic circulation
  46. 46. PULMONARY CIRCULATION - Deoxygenated blood from the heart is pumped from the right ventricle through the pulmonary artery. -Oxygenated blood from the lungs then return to the left atrium through pulmonary vein.
  47. 47. SYSTEMIC CIRCULATION - Supplies blood to all parts of the body, except the lungs. -Oxygenated blood is pumped from the left ventricle into the aorta before it is distributed by: (a) subclavian arteries to the arms (b) carotid arteries to the neck and head -Superior vena cava collects deoxygenated blood from the upper part of the body and return it to the right atrium. -Inferior vena cava collects deoxygenated blood from the lower part of the body and returns it to the right atrium. -Heart receives blood form a pair of coronary arteries leading from the aorta.
  48. 48. -The flow of blood during blood circulation is maintained by: a) the pumping action of the heart – ventricles press the blood through the arteries into the capillaries. b) contraction and relaxation of skeletal muscle around the veins during the normal body movements to propel the blood to the heart. c) inhalation movements – during inspiration, the thoracic pressure is reduced, and this aids in drawing blood back into the heart.
  49. 49. THE PUMPING OF HEART - Two atria contract simultaneously: a) blood from the right atrium is forced into the right ventricle b) blood from left atrium is forced into the left ventricle - Two atria relax simultaneously: a) left atrium receives blood from the pulmonary veins b) right atrium receives blood from the superior upper part of body) and inferior (lower part of body) vena cavae. - After a slight pause, two ventricles contract (systole) simultaneously : a) blood in the right ventricle is forced into the pulmonary artery and blood in the left ventricle is forced into the aorta.
  50. 50. b) Blood in the right ventricle and the left ventricle is prevented from flowing back into the atria by the closure of bicuspid tricuspid valve. c) The simultaneous closure of the two valve will produce “lub” sound. -When 2 ventricles relax (diastole): a) the volume of the ventricles increase; drawing in blood from the atria. b) blood in the arteries (pulmonary artery and aorta) is prevented from flowing back to the ventricles by the closure of both the two semilunar valves, produce “dub” sound. -A heartbeat consist of a systole (“lub” sound) and a diastole (“dub” sound). - Normal heartbeat – 72 times/minute
  51. 51. BLOOD PRESSURE AND THE REGULATORY MECHANISM - Blood pressure is the force that blood exerts on the walls of the blood vessels, which is measured in millimetres of mercury (mmHg). - Caused by the contraction of the heart and by the muscles that surround blood vessels. - Blood pressure in the arteries is highest when the ventricles contract (systole) and force the blood into the pulmonary artery and the aorta. - Blood pressure decreases when the two ventricle relax (diastole).
  52. 52. -Normal blood pressure : 120/80 mmHg , 120 over 80 - The first number represent the pressure when the ventricles contract. -The second number represents the pressure when the ventricle relax. -In human, blood pressure is regulated by: a) nervous system – send impulse to speed up or slow down the heart rate b) kidney – regulate blood pressure by controlling the amount of fluid in our blood. When blood pressure is too high, kidneys remove water from the blood (less volume of blood), blood pressure become lower.
  53. 53. REGULATION OF BLOOD PRESSURE BY THE NERVOUS SYSTEM -Baroreceptor / stretch receptors – groups of nerve fibres within the walls of the carotid sinus (a swelling of the internal carotid artery) and the aortic.
  54. 54. -If blood pressure in the arteries is high: a) the baroreceptors detect it and send impulses from the sensory nerves to the cardiovascular centre in the medulla oblongata of the brain. b) Cardiovascular centre of the brain sends impulses (in the vagus nerve of the parasympathetic nervous system) to the heart to decrease the heart rate and also the cardiac output (volume of blood pumped by the heart).
  55. 55. c) At the same time, the cardiovascular centre sends nervous impulses to relax the smooth muscles of the arterioles, causing the arterioles to dilate (vasodilation) and reduce the resistance to blood flow. d) A reduced heart rate, a lowered cardiac output and a vasodilation of the arterioles will help to reduce the blood pressure.
  56. 56. (Baroreceptor) / medulla Parasympathetic Decreased Heart Rate and cardiac output Stimulate smooth muscle in the arterioles to dilate High
  57. 57. -If blood pressure drops too low: i) The baroreceptors detect it and stimulate the cardiovascular centre to send the nervous impulse (via the sympathetic nervous system): • to increase the heart rate (via the sympathetic nerve) • to stimulate the smooth muscles in the arterioles to contract (vasoconstriction) to decrease flow of blood. ii) An increased heart rate and a vasoconstriction of the arterioles will help to increase blood pressure.
  58. 58. (Baroreceptor) /medulla Stimulate smooth muscle in the arterioles to contract
  59. 59. CIRCULATORY SYSTEMS IN OTHER ANIMALS INCOMPLETE e.g. amphibians COMPLETE e.g. humans, birds
  60. 60. -Single circulation – blood passes through the heart only once in a complete circulation of the body -Double circulation – blood passes through the heart twice in a complete circulation of the body •lizards, snakes, and turtles have incomplete septums, oxygenated blood and deoxygenated blood may mix to some degree. •In crocodiles a complete septum and a valve prevent this from happening.
  61. 61. FISH - Has a simple two-chambered heart, consisting of an atrium and ventricle that are separated by atrio-ventricular valve. -Atrio-ventricular valve prevents the backward flow of the blood from the ventricle into the atrium. -Blood circulation: a) ventricle of the heart pumps deoxygenated blood to the capillary network of the gills to be oxygenated.
  62. 62. b) Arteries carry the fully oxygenated blood from the gills to various parts of body capillaries. c) Deoxygenated blood from the body capilaries returns to the atrium of heart. Heart (ventricle) Gills Body Heart (atrium) -Fish have a a) single circulation – blood is pumped through the heart only once. b) closed circulation – blood is always contained within the heart and blood vessels. -Disadvantage of the single circulation – single heart has to pump blood through the gill capillary network and the body capillary network. Thus, reduce blood pressure and sluggish flow of blood
  63. 63. AMPHIBIANS - Has 3 chambered heart, consist two atria and one ventricle (partially divided). -Blood circulation: • Pulmonary artery carries blood from the ventricle to the pulmonary capillary network, where gas exchange occurs. • Pulmonary vein returns oxygenated blood from the lungs to the left atrium of the heart • Vena cava returns deoxygenated blood from the systemic capillaries to the right atrium. • Single ventricle receives both oxygenated blood and deoxygenated blood. Pulmonary artery Pulmonary vein Vena cavae Aorta
  64. 64. • When the ventricle contract, a mixture of oxygenated and deoxygenated blood is pumped into both the pulmonary artery and aorta. -Amphibians have: • incomplete double circulation – although blood is pumped through the heart twice in a circulation, there is a mixing of oxygenated and deoxygenated blood in the ventricle. • closed circulation – blood is contained within the blood vessel -Advantage for incomplete double circulation is higher blood pressure, so the flow of blood is more efficient compared to fish.
  65. 65. BIRDS -Have 4-chambered heart that completely separate oxygenated and deoxygenated blood. -Septum of the heart is complete, providing 2 separate circulatory systems:  Pulmonary circulation – right atrium and right ventricle receives deoxygenated blood from the body and send it to the lungs  Systemic circulation – the left atrium and left ventricle receive oxygenated blood from the lungs and sends it to the body tissues.
  66. 66. -Birds have higher metabolic rate than humans, the pulse rate of chicken can reach 400 beats/minute. -Its ventricle have more muscle mass and less chamber space than human.
  67. 67. BLOOD CLOTTING -Importance of blood clotting: a) prevents excessive blood loss which make blood pressure dangerously low. b) prevents the entry of microorganisms and foreign particles into the body c) forms scabs and helps in the healing of wounds d) maintains the circulation of blood in a closed system
  68. 68. MECHANISM OF BLOOD CLOTTING - Blood flowing in blood vessels is prevented from clotting by a substance called heparin (family of carbohydrate) found in the blood plasma. -Blood clotting is initiated by the: a) clotting factors from damaged cells  e.g. fibrinogen, prothrombin, thromboplastin, calcium ions b) Collagen fibres from damaged blood vessel wall - Mechanism of blood clotting:
  69. 69. IMPAIRED BLOOD CLOTTING MECHANISM a) Deficient in calcium and vitamin K: o It will take a longer time than normal o cause bleeding b) Haemophilia  Blood is unable to clot because the deficiency of blood proteins  Cause bleeding or death c) Thrombosis  Thrombosis is the formation of a clot or thrombus inside a blood vessel, blocking the flow of blood.  The blockage stops the tissues from receive blood flow and oxygen  cause damage to the tissues in that area
  70. 70.  A clot formed in coronary artery cause heart attack. A clot formed in the brain cause strok. Heart attack Strok
  71. 71. LYMPHATIC SYSTEM -The space between tissue cells – interstitial space -Interstitial space is filled with a colourless liquid – interstitial fluid -The formation of interstitial fluid and lypmh : a) Blood enters the arterial ends of the capillary network under high pressure b) Endothelial cell walls of the capillaries act as filter. Large cellular components (red blood cell) and large protein molecules cannot pass through. Only water and dissolved substances of the plasma (oxygen, products of digestion and hormone) can diffuse out of the cell.
  72. 72. c) Blood plasma diffuse out into the interstitial spaces to form interstitial fluid. d) The process of producing interstitial fluid from the blood is called ultrafiltration. e) The interstitial fluid circulates among the tissue cells and returns to the blood circulatory system in two ways: (i) passes into the venous end of the capillaries
  73. 73. ii) drain into the lymph capillaries as lymph f) Lymph and interstitial fluid have the same composition, the difference is interstitial fluid is found between the cells, while lymph is found inside the lymph vessel.
  74. 74. Fluid Characteristic Blood Plasma Interstitial fluid Lymph Appearance Red Light yellow Pale brown colour Clear watery fluid, sometimes yellowish Location Within the heart, arteries, veins and capillaries Interstitial space Within the lymph vessel Originate from Bone marrow, lymph nodes, thymus gland Water and dissolved substances absorbed by alimentary canal Plasma Interstitial fluid and fatty acids absorbed by the ileum Function Transport and defence Transport over long distance Transport over short distance Transport and defense Moved by Pumping of the heart, muscle contraction, breathing action Hydrostatic and osmotic forces Hydrostatic forces, muscle contraction, breathing action
  75. 75. Direction of flow Circulates around the body and back to the heart Out of the arterial end and returns into the venous ends of the capillaries From the tissues and towards the heart
  76. 76. Contents Blood Plasma Interstitial fluid Lymph Water     Plasma proteins (albumin, globulin, fibrinogen)   X (proteins remain in blood capillaries)  Platelets  X X X Leucocytes  X X  (lymphocytes ) erythrocytes  x x x Ions (Na+ ,K+ ,Ca2+ )     Nutrients (glucose, amino acids, fatty acids, vitamin)     (more fats from lacteal)
  77. 77. Waste products (urea, uric acid)     Gases     Hormones     - The importance of interstitial fluid: a) tissue fluid fills the interstitial spaces between the tissue cells, providing them with a stable external environment b) nutrients and oxygen from the bloodstream in the capillary network diffuse across the capillary walls into the interstitial fluid and then into the tissue cells. c) waste products that accumulate within the active cells diffuse in the opposite direction across the interstitial fluid from the cells to the capillaries.
  78. 78. STRUCTURE OF THE LYMPHATIC SYSTEM -Lymph is found inside the lymph vessels. -The composition of lymph is similar to interstitial fluid but with more fats. -Main structures of the lymphatic system: a) Lymphatic capillaries: - larger in diameter than the blood capillaries - located next to blood capillaries in tissue spaces - very permeable to tissue fluid - found as lacteals in the villi of the small intestine
  79. 79. b) Lymphatic vessel - formed from lymph capillaries - similar as veins (have 3 layered walls), but have thinner walls and more valves - carry lymph away from the tissues c) Lymph node - small round or oval structures - contains a network of fibres and irregular channels acting like a filter - filter lymph when it flows through the nodes - eliminates bacteria and cellular debris by phagocytosis
  80. 80. d) Spleen - an organ located on the left side of the abdomen near the stomach - produce lymphocytes, filters the blood, store blood cells, destroy old blood cells. e) Lymph ducts (larger lymph vessel) - lymph vessels drain their contents back into the bloodstream - Thoracic duct (left lymphatic duct) and right lymphatic duct.
  81. 81. -Movement of lymph within the lymphatic system; a) interstitial fluid drains into the lymph capillaries to form lymph b) lymph capillaries join together to form larger lymphatic vessel c) the walls of the lymphatic vessels contain valve-like pores that allow the entry of cell debris and bacteria d) the contraction and relaxation of the skeletal muscle contract and relax the lymphatic vessel, pushing lymph to the lymph nodes e) Semilunar valves within the lymphatic vessels keep the flow of lymph in one direction
  82. 82. f) Lymph nodes remove the suspended solid and bacteria from the lymph by phagocytosis g) The lymphatic vessels return the lymph to the heart via two ducts: i) Right lymphatic ducts - drain lymph from the right arm, right side of head and the thorax and opens into the right subclavian vein near the heart ii) the thoracic duct (left lymphatic ducts) drains lymph from the rest of the body into the left subclavian vein near the heart
  83. 83. Right subclavian vein
  84. 84. - Lymph is moved along the lymph vessel by: a) Hydrostatic pressure of interstitial fluid- push lymph along the lymphatic capillaries b) Contraction of skeletal muscle – lymph flow along the lymphatic vessel c) Valves within lymphatic vessel – lymph flow away from the tissue to the heart in one direction d) Inhalation – reduce pressure in thoracic cavity and drawing lymph towards the thorax.
  85. 85. Lymphatic capillaries Lymphatic vessel Lymphatic nodes Lymphatic vessel Right lymphatic duct Left lymphatic duct Superior vena cavae Heart Right subclavian vein Left subclavian vein
  86. 86. -Function of lymphatic system: a) transport interstitial fluid back to the bloodstream b) distributes fluids and nutrients in the body and drains excess fluids and protein so that tissues do not swell up c) transport fat and fat-soluble vitamin from small intestine into the blood circulation d) provides immunological defence against disease by: (i) produce lymphocytes and antibodies to fight and destroy microorganisms (ii) filtering out microorganisms and other foreign substances from the lymph by the lymph nodes and from the blood by the spleen.
  87. 87. WHEN INTERSTITIAL FLUID FAILS TO RETURN TO THE CIRCULATORY SYSTEM -Too much interstitial fluid is produced, but little or none is reabsorbed back into the circulatory system. -Cause the organs and tissues of the body to swell up- oedema -Oedema can be caused by: a) increase in the capillary blood pressure, forcing an excess fluid leakage to the interstitial space b) blockage of the lymphatic vessel which slows down the drainage of excess interstitial fluid.
  88. 88. -Elephantiasis – caused by the blockage of the body’s lymphatic system by certain parasitic round worms leading to oedema.
  90. 90. -First and second lines of the defence mechanism: a) nonspecific – they do not distinguish infectious pathogens b) inborn – they are natural built-in defences - for example :skin – act as barrier to the pathogens : phagocytes –engulf pathogens c) provide immediate protection against invading pathogens. -Third line of defence mechanism: a) specific – distinguish specific pathogens. For example, lymphocytes produce specific type of antibody to fight pathogens. b) Acquired and developed c) takes a longer time to be effective, but remember the past infections. So, it can be better prepared for future invasions by the same type of pathogens.
  91. 91. FIRST LINE DEFENCE -Skin • provides a continuous layer protect a whole body. • Few microorganisms can penetrate the layers of dead cells at the surface of the skin. A cut in the skin allow the microorganisms to enter the body. • Blood clots plug the wound and prevent the entry of microorganisms.
  92. 92. -Mucous membrane • lines all tissues and organs such as respiratory, digestive, urinary and reproductive tracts. • secrete mucus, which is thick, slippery liquid that protect the membrane and keep it moist and soft. • protect the interior surfaces of the body that may be exposed to pathogens -Both the skin and mucous membrane are nonspecific defence because: a) use the same barrier against all types of microorganisms b) not directed against any particular pathogens
  93. 93. CHEMICALS USE BY SKIN AND MUCOUS MEMBRANE -Perspiration/sweat • Excreted from sweat glands contains lysozyme and acids that destroy harmful bacteria and inhibits the growth of fungi. -Lysozyme • also present in tears, saliva and nasal secretion -Sebum • low pH • prevents the growth of certain microorganisms and fungi
  94. 94. - Mucus • trap microorganisms and dirt particles. -Cilia • little hair that carry the mucus, trapped microorganisms and dirt towards the glottis to the throat - Acid in gastric juice • kills microorganisms present in food or water on in swallowed mucus.
  95. 95. SECOND LINE DEFENCE -Take action when pathogens can penetrate the skin or mucous membrane. -Nonspecific immune response because use same method of defence to all type of pathogens. -The nonspecific immune response include: a) phagocytosis – carried out by white blood cells such as neutrophils, macrophages and occasionally eosinophil. b) natural killer cells – destroy infected cells and pre- cancerous cells.
  96. 96. c) Inflammation – involve redness, heat, swelling, pain d) Fever – high temperature kill bacteria by denaturing their protein and help healing process
  97. 97. PHAGOCYTOSIS -Phagocytosis (phago = eat; cyte = cell) attack, engulf and destroy pathogens -Two common types of phagocytes are neutrophils and macrophages -Neutrophils: • circulate freely through the blood vessels • squeeze between cells of the capillary wall to reach the site of infection, attracted by the chemicals released by the microorganisms (chemotaxis). • first phagocytes to arrive at the injured tissues before macrophages.
  98. 98. -Macrophages • another type of phagocyte developed from monocytes (white blood cells) • longer-lived and arrived at the inflamed site some 3-7 days later after the neutrophils.
  101. 101. INFLAMMATION
  102. 102. THIRD LINE OF DEFENCE - Immunity : ability of the human body to resist infection -Immune response : body’s defence reaction when an antigen is recognized and specific antibodies are produced by lymphocytes to defend against pathogens -Antigen : foreign protein molecule (bacteria, virus, fungi) that enter the body and stimulate the production of antibodies -Antibody : a protein substance produced by immune system to recognize antigen.
  103. 103. : Y shaped protein molecule that also known as immunoglobulin. : function – destroy or weaken a pathogen and neutralise its toxin -2 white blood cells that involved: a) lymphocytes – produce antibodies b) macrophages - phagocytosis
  104. 104. - Antigen recognition and the production of antibodies takes place when:
  105. 105. WAYS WHICH ANTIBODIES HELP TO DEFENSE BODY a) Agglutination b) Opsonisation c) Neutralisation d) Precipitation
  106. 106. AGGLUTINATION -Antibodies and antigens stick together and the microorganisms clump together in large numbers making the antigens harmless. -The inactive pathogens are then ingested by phagocytes.
  107. 107. OPSONISATION - An antigen is covered with antibodies which make it easier for ingestion by phagocytes. -An antibody-coated pathogen can be made to burst (cell lysis), killing it before being ingested by phagocytes. Cell produce from differentiation of monocytes
  108. 108. NEUTRALISATION - Antibodies bind to the toxins (antigens), neutralise the poison of the toxin. -When an antibody binds to a toxin, it is called antitoxin -The neutralised toxin is then ingested by the phagocytes -Virus and bacteria are similarly neutralised to prevent them from attach and penetrate the body cells.
  109. 109. PRECIPITATION - Antibodies bind to the soluble antigens, cause them to precipitate. - Then, they will be ingested by phagocytes.
  110. 110. VARIOUS TYPES OF IMMUNITY -After an initial infection, some lymphocytes are kept in the body as a “memory”. This helps the body to defend itself against further attacks by the same antigens. -As this “memory” may last for years, the body is said to be immune to the disease. -There are 2 types of immunity: a) active immunity b) passive immunity
  111. 111. Active immunity Passive immunity • Acquired when lymphocytes in the body are activated by antigens to produce antibodies • Occur when a person becomes temporary immune to an antigen by receive ready-made antibodies from another person or animal. • Lasts for a long time • Lasts only for a short time as the antibodies eventually die off or removed from the body as foreign proteins.
  112. 112. - Some vaccines are made from: a) live attenuated (weakened) pathogens – measles, mumps, rubella, chickenpox b) killed pathogens – influenza, Japanese encephalitis (J.E), hepatitis A, typhoid fever c) toxoid – bacterial toxin that has been weakened and no longer toxic – tetanus, diphtheria
  113. 113. EFFECTS OF HIV ON THE BODY’S DEFENCE MECHANISM - HIV : H – for Human, because it infect humans I - Immunodeficiency, because virus attack the body’s immune system, weakening it so that it cannot fight other deadly disease V – Virus belong to the group, retrovirus
  114. 114. - AIDS – Acquired, person get HIV from another infected person. - Immune, refer to the body’s defence system - Deficiency , making the immune system deficient - Syndrome, refer to a group of illness
  115. 115. - When the immune system is weakened: a) the body becomes vulnerable to a variety of infections and cancers. b) other infections take advantage of the weakened immune system. These called as “ opportunistic infections”. c) the body becomes so weak, and the person dies.
  116. 116. - Transmission of HIV by: a) direct contact with infected blood b) sexual contact with an HIV-infected person c) HIV-infected mothers to infants during pregnancy, delivery or breastfeeding d) sharing needles with drug users who are infected with HIV - HIV is not transmitted a) by insect bites b) through the air c) hugging, touching, handshaking d) living in the same house e) sharing food and water f) sharing cup, glass, plates etc.
  117. 117. TRANSPORT OF SUBSTANCES IN PLANTS - Transport system is necessary because: a) CO2 is absorbed and transported to photosynthesising cells b) O2 is released from photosynthesising cells into the atmosphere. c) water and minerals from the roots have to be transported to the leaves d) photosynthetic products (sugar, amino acids) have to be transported away from the leaves for storage and to other tissues. - Transport functions are carried out by xylem and phloem.
  118. 118. VASCULAR TISSUE IN STEM, ROOT AND LEAF - Consist of phloem and xylem. - Roles of vascular tissue: a) xylem – transport water support the plants b) Phloem – transport nutrient - Vascular bundle • strand of conducting tissue (xylem and phloem) • Stem – phloem is located outward facing the epidermis, xylem is toward the centre.
  119. 119. • Leaf – phloem facing at the lower part, xylem at the upper part. - A mature vascular bundle consist of xylem, phloem and cambium. Cambium separate the xylem and phloem.
  120. 120. STRUCTURE OF VASCULAR TISSUE - The main tissues in a stem of a dicot : a) epidermis b) cortex, that contain collenchyma, chlorenchyma and endodermis c) vascular bundle, that contain phloem and xylem d) the pith
  121. 121. -The vascular bundles in the stem of a dicot are arranged in a ring. - The cambium is sandwiched between the xylem and phloem. -Cortex is located outside of the vascular bundle ring in the stem.
  122. 122. - The pith is the tissue located inside the vascular bundle ring. - Parenchyma- cells with thin primary walls that retain their protoplasm - Collenchyma - cells with thick primary walls that retain their protoplasm - Sclerenchyma- cells with lignified secondary walls that have lost their protoplasm at maturity, i.e. are 'dead' - Chlorenchyma - Containing Chloroplast
  123. 123. VASCULAR TISSSUE IN THE LEAF OF A DICOT - Vascular bundle consist of: a) xylem – faces the upper epidermis b) cambium – that divides to produce xylem and phloem cells c) phloem – faces the lower epidermis
  124. 124. VASCULAR TISSUE IN THE ROOT OF A DICOT - Vascular tissue is packed in the centre. - Other structures observed in the root: a) root hair – extension of the epidermal cells - increase absorption of water by the surface b) epidermis – absorption of water and minerals c) cortex – consist of endodermis and parenchyma cell that store starch. d) pericycle – layer of parenchyma cells inside the endodermis where lateral root originate
  125. 125. RELATING THE STRUCTURE OF XYLEM TO TRANSPORT - Functions of xylem: a) transport water and dissolved minerals from the root to other parts of cell (one way). b) provide mechanical support - Xylem consist: a) vessel b) tracheid c) fibre (rigid secondary cell wall for support and protection) d) parenchyma (store food)
  126. 126. - Vessels • Dead cells that form hollow tube, which connect the root to the leaf. • Deposited by lignin to strengthen it and support the stem • The structure of xylem vessel is adapted to transport water because : o it has continuous lumen without any walls and protoplasm within it to allow the flow of water and minerals salts o the walls are lignified to provide strength and prevent the water from collapsing
  127. 127. - Tracheids • Dead cells when matured • Long, slender cells with tapered, overlapping end • Have thick, hard, lignified secondary cell wall • Smaller lumen than xylem vessel • No sieve plates at the end walls
  128. 128. - The movement of water in tracheids: a) water moves sideway through the pits in adjacent tracheid cells before going upward b) movement of water upwards is slower than in vessel
  129. 129. RELATING THE STRUCTURE OF PHLOEM TO TRANSPORT - Transport food such as sugars and amino acids from the leaves for storage in stem and root - Transport food from storage in roots to other parts of plants. - 2-way flow
  130. 130. - Components of phloem : a) sieve tube b) companion cells c) parenchyma d) fibres
  131. 131. a) Sieve tube - made up of a single row of elongated and thin-wall living cells called sieve tube cells. - A mature sieve tube has only thin layer of cytoplasm, no nucleus or central vacuole, lost most of its organelles - Sieve plates separate sieve tube cells at both ends. - Sieve plates allow cytoplasmic connections between vertically-stacked cells that will transport food by diffusion and active transport.
  132. 132. b) Companion cell - lie next to each sieve tube cell - has a nucleus, endoplasmic reticulum, ribosomes and mitochondria - provide metabolic support for the sieve tube cells in the transport of manufactured food
  133. 133. REMOVING A RING OF PHLOEM TISSUE FROM A PLANT - Phloem can be removed by cutting a ring of bark and removing it from the stem. - This “ringing” cuts off the supply of food downwards beyond the ring. - Food that is transported from the leaves down the stem in the phloem accumulates above the ring. - After a few weeks, the bark above the ring swells. - This shows that sugar transported downward in the phloem.
  134. 134. TRANSLOCATION - Movement of sugars and other organic materials from one place to another within the plant body -The importance: a) distribute food to other parts of the plants such as seed, root, tuber. b) without translocation, plants would not be able to metabolise food for energy, growth and maintenance
  135. 135. TRANSPIRATION -The loss of water by evaporation from the parts of plants through the stomata of the leaves. -Transpiration occur: a) mainly through the open stomata – 90% of water b) waxy cuticle – very little water escape through the cuticle of the leaves c) lenticels of woody stem
  136. 136. PROCESS OF TRANSPIRATION - There are intercellular air spaces among the spongy mesophyll cell. - Spongy mesophyll cell has moist surface - Water evaporates from these cells into the intercellular spaces and diffuse through the stomata to the drier air outside the leaf.
  137. 137. - As these border of mesophyll cells lose water, their cell sap becomes more concentrated and therefore draws water by osmosis from the cells deeper inside the leaf. - These cells in turn draw water from the xylem of the plant veins by osmosis. -Water forms an unbroken water chain (by cohesion and adhesion force of water molecule) from the outer surface of leaves to the roots. -As the water evaporates from the plant leaves, they attract other water molecules which are still in the plants to the top.
  138. 138. Transpiration in plants
  139. 139. THE IMPORTANCE OF TRANSPIRATION - The roles of transpiration: a) cooling the plants  As water evaporates from the leaves, it remove heat from the plant in the form of latent heat of vaporisation, thereby cooling the plant b) Provide support by turgor pressure  because water diffuse from higher concentration to lower concentration, all the cells in the plants become turgid.
  140. 140. c) Transport water and mineral salts  Transpiration create a transpiration pull, lifting water and dissolved mineral salts up the plant from the root to the leaf. - Negative effect of transpiration: a) if the rate of transpiration exceeds the intake of water by the roots, plants growth would be affected b) any excess loss of water causes the plant to wilt and die
  142. 142. Absorption and movement of water in plant
  143. 143. MOVEMENT OF WATER FROM SOIL TO ROOT - The cell sap of root hairs is more concentrated than soil water. -The high solute concentration of the cell sap is due to the active transport of the solute molecules into the cell. -Water moves from the soil water into the cell sap of root hair by osmosis. -When water enter the vacuole of the root hair cell: a) the cell sap becomes dilute and its concentration and osmotic pressure are reduced
  144. 144. b) the turgor pressure of the cell increase and reduce its suction pressure c) the cell sap become hypotonic the cell sap of adjacent cell -Water from hypotonic root hair cell sap move to adjacent hypertonic cells. -Therefore, water move out from the root hair cell into the adjacent cells, cortex and then into the xylem.
  145. 145. PATHWAY OF WATER UP THE STEM -The movement of water in the xylem up the stem is effected by: a) root pressure b) transpiration pull c) cohesion- adhesion theory of water
  146. 146. a) Root pressure - the ‘pulling’ of water into the xylem from the surrounding cells produces a hydrostatic pressure inside the xylem, forcing water upwards. - this positive pressure is called root pressure.
  147. 147. b) Transpiration pull - when water evaporates from mesophyll cells, their cell sap becomes more concentrated. - these mesophyll cells in turn draw water by osmosis from the cells found in deeper inside the leaf. - these inner cells which are adjacent to the veins draw water from them by osmosis. - the column of water is continuous from the root up to the leaves
  148. 148. - as the mesophyll cells ‘suck’ water from the xylem vessel, the whole column of water is pulled up from root to leaf (due to cohesive and adhesive of water molecule) - The pulling force is called transpiration pull
  149. 149. c) Cohesion-adhesion theory of water - the continuous flow of water through the xylem depends on two important properties: i) cohesion – attraction between water and water molecules ii) adhesion – attraction between water and xylem vessel - this is why water forms a continuous water column up the xylem vessel while being sucked up by the transpiration pull.
  150. 150. EXTERNAL CONDITIONS AFFECTING TRANSPIRATION - The amount of water lost from the plant in transpiration depend on: a) light intensity b) temperature c) relative humidity d) air movement
  151. 151. a) Light intensity - guard cells regulate the size of the stomata openings: i) under high light intensity, the stomata openings enlarge and transpiration increase ii)under low light intensity, the stomata opening decrease and transpiration decreases - the rate of transpiration is directly proportional to the intensity of light.
  152. 152. b) Temperature - High temperature increase the kinetic energy of water molecules which increases the rate of diffusion through the stomata - the rate of transpiration is directly proportional to temperature
  153. 153. c) Relative humidity - intercellular air spaces in the leaf are saturated with water vapour. - water vapour diffuse from the intercellular space to the air outside. - this saturated water vapour diffuse out of the leaf at a : i) higher rate if the air outside is dry (higher relative humidity) ii) lower rate if the air outside is damp (lower rate humidity)
  154. 154. Graph humidity
  155. 155. d) Air movement - In still air, water vapour that diffuse out through the stomata forms a layer of still moist air around the leaf - Moist air decrease the rate of water vapour diffusion and drop the rate of transpiration. - Moving air carry away this layer of moist air formed around a leaf and increase the rate of transpiration. - The rate of transpiration is directly proportional to the velocity of the air current.
  156. 156. THE OPENING AND THE CLOSING OF THE STOMA - The uneven thickening of the outer and inner wall of the guard cells provide a mechanism for the opening and the closing of the stoma. - The inner concave wall of each guard cell is very thick, but the outer convex wall is thinner - For high light intensity, the rate of photosynthesis increase and the guard cells absorb water and become turgid.
  157. 157. - Water in each guard cell push the thin outer wall that enlarge the stomata opening. - Under poor light, the turgor pressure of the guard cells drop, it become flaccid and the stoma become smaller or closes.
  158. 158. HOW STOMA OPENS IN DAYLIGHT - Photosynthesis take place in the guard cell Sugar accumulates in guard cell Osmotic pressure in guard cell increase Water enter the guard cell by osmosis Guard cell become turgid Stoma opens
  159. 159. - Photosynthesis take place in the leaf cells Concentration of CO2 in the leaf cell drops pH goes up Starch in the cell is converted into sugar Stoma open
  160. 160. HOW STOMA CLOSES AT NIGHT - Photosynthesis in guard cells stop Concentration of sugar in guard cell decrease Osmotic pressure in guard cell decrease Water leaves guard cell by osmosis Guard cell flaccid Stoma close
  161. 161. - Photosynthesis in the leaf cells stop Concentration of CO2 in intercellular space rise pH goes down Sugar is convert to starch Stoma close