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ICSE BIOLOGY THE CIRCULATORY SYSTEM NOTES

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~1~ DishaEducentre Exhaustive Notes 6. The Circulatory System THE CIRCULATORY SYSTEM ~ Part A: Body Fluids ~ I. Definitions and Explanations The study of blood is called as haematology. When blood circulates in a closed manner through blood vessels, then it is called as closed vascular system. Example: in chordates. Fluids of the human body that remain located in particular organs and do 3. not circulate are called as non-circulating fluids. Example: aqueous humour, vitreous humour, synovial fluid. Blood is a bright red viscous fluid that flows through all the vessels of the 4. Blood human body except the lymph vessels. It constitutes around 8% of the total body mass. The fluid component of blood, which constitutes around 55-60% of its total 5. Plasma volume is called plasma. 6. Erythrocytes a.k.a. Erythrocytes are nucleated, biconcave disc shaped bodies present in the blood. They contain haemoglobin and are useful in carrying oxygen and Red Blood carbon dioxide to their respective destinations in the body. Corpuscles Leucocytes are non-nucleated, amoeboid (irregularly shaped) bodies present 7. Leucocytes a.k.a. in the blood. They can move by developing processes called pseudopodia. White Blood They are responsible in protection of body from infections. Corpuscles Haemoglobin is an iron-protein complex that is found in erythrocytes. The 8. Haemoglobin iron component is called haemin and the protein component is called globin. It combines with oxygen and carbon dioxide and carries them to their responsible destinations. The process of formation of the red blood corpuscles from the bone marrow 9. Erythropoiesis of long bones such as the femur and the humerus is known as erythropoiesis. The process of formation of the white blood corpuscles is known as 10. Leucopoiesis leucopoiesis. Thrombocytes or blood platelets are minute oval or round structures that are 11. Thrombocytes non-nucleated, which are present in the blood. They are responsible for a.k.a. Blood blood clotting. Platelets Megakaryocytes are large cells in the red bone marrow where thrombocytes 12. Megakaryocytes are produced. Thrombokinase is a chemical substance released by thrombocytes by self13. Thrombokinase disintegration. The chemical initiates the process of blood clotting. It is a.k.a. called as Factor X or Stuart Factor in recent times. Thromboplastin The process in which leucocytes and particularly the neutrophils engulf 14. Phagocytosis particle-like solid substances, especially bacteria, is known as phagocytosis. The reaction of tissues to injury and to localised invasion of germs is known 15. Inflammation as inflammation. An inflamed region will show local heat, redness, swelling and pain, etc. The movement of the leucocytes (mainly the monocytes and neutrophils) 16. Diapedesis through the walls of the blood vessels is known as diapedesis. Lymphocytes are agranularleucocytes which produce antibodies to kill and 17. Lymphocytes neutralise germs and improve the body s immunity. 1. 2. Haematology Closed Vascular System Non-circulating Fluids Notes Prepared by Neil Valentine D Silva DishaEducentre Exhaustive Notes 18. Pus 19. Antibodies 20. Antitoxins 21. Immunity 22. Leukaemia 23. Prothrombin and Thrombin 24. Fibrinogen and Fibrin 25. Serum 26. Blood Clot or Thrombus 27. Blood Transfusion 28. Universal Donor 29. Universal Recipient ~2~ The Circulatory System The sticky white mass produced when damaged cells are engulfed and destroyed by leucocytes is called as pus. It contains damaged cells and leucocytes. Antibodies are chemical substances that are free to circulate in the blood plasma. They can kill pathogens that enter the bloodstream. Antitoxins are chemical substances that neutralise and detoxify the poisonous effects of toxins in the body. Immunity is the natural resistance of an organism against diseases. It is provided by the lymphocytes. Leukaemia is a type of cancer of the tissues that form leucocytes. In this condition, the number of leucocytes becomes much higher than the erythrocytes. It is a fatal condition. Prothrombin is a precursor for blood clotting present in the plasma. Under the influence of calcium ions, the enzyme thrombokinase converts it into thrombin. Fibrinogen is a blood clotting factor in the plasma. Under the influence of calcium ions, thrombin converts it into fibrin, an insoluble substance. Plasma from which the protein fibrinogen has been removed is known as serum. A blood clot or thrombus is a network of insoluble proteins (fibrin) in which the formed elements of the blood are trapped. The process of injecting blood into the bodies of patients who need it is known as blood transfusion. A person with a blood group that can be donated to anyone is known as universal donor. Blood group O is called as the universal donor. A person with a blood group that can be accepted from anyone is known as universal acceptor. Blood group AB is called as the universal recipient. II. Questions-Answers 1. What are the characteristics of human blood? characteristics of human blood are:It is thicker than water. It is slightly heavier than water. Its pH lies within the range of 7.35 to 7.45, which makes it slightly alkaline, Its temperature is maintained at around 38 C. ANSWER The 2. Which are the main fluids in our body? Where are they contained? main fluids in our body are blood, tissue fluid and lymph. Body Fluid Location in the Body Blood contained in heart and blood vessels such as arteries, veins and capillaries Tissue Fluid contained in the interspaces between cells in organs Lymph contained within lymph vessels and lymphatic organs such as spleen and tonsils ANSWER The 3. What are the different types of circulation found in animals? Give examples. are two different types of circulation found in animals open and closed. Open Circulation Blood flows through open spaces in the body as there are no blood vessels. Examples: insects Closed Circulation Blood flows through closed blood vessels such as arteries, veins and capillaries. Examples: mammals ANSWER There (i) (ii) Notes Prepared by Neil Valentine D Silva DishaEducentre Exhaustive Notes 4. ~3~ The Circulatory System What are the characteristics of blood? characteristics of blood are as follows:It is deep red viscous fluid. It is slightly salty to taste. It is slightly alkaline in nature; its pH lies between 7.35 and 7.45. It is never stationary; it is always in a state of motion in the blood vessels. ANSWER The 5. Describe the functions of blood. functions of blood can be divided into two branches transportation and protection. Transportation It helps in the transportation of digested substances such as glucose, amino acids, vitamins and mineral acids, etc. from the alimentary canal to the tissues. It helps in the transportation of oxygen from lungs to tissues. It helps in the transportation of carbon dioxide from tissues to lungs. It carries excretory material from the tissues to liver, kidney and skin where they are detoxified or eliminated. It distributes hormones secreted by the endocrine glands to specific target organs of the body. It helps in thermoregulation of the body by distributing heat uniformly. Protection It forms a hard covering known as clot at the point of injury. This prevents further loss of blood and entry of pathogens from the injured location. The leucocytes in the blood engulf bacterial pathogens and destroy them. It produces antitoxins and antibodies which eliminate toxins and pathogens entering the body. ANSWER The (i) (ii) 6. Explain how blood helps in the exchange of gases. ANSWER Blood exchanges oxygen and carbon dioxide between the body and the external environment. Haemoglobin present in the body helps in the exchange of both these gases. Haemoglobin combines with oxygen introducedin the lungs by respiration to form a complex known as oxy-haemoglobin. This gives blood its deep red colour. This combined oxygen is then carried from the lungs to the tissues. Hb + O2 Hb. O2 In the same manner, haemoglobin combines with carbon dioxide eliminated by the body tissues to form a complex known as carbamino-haemoglobin. This combined carbon dioxide is then carried from the tissues to the lungs from where it is expelled out. Hb + CO2 Hb. CO2 7. Explain how blood helps in the exchange of gases. ANSWER Blood exchanges oxygen and carbon dioxide between the body and the external environment. Haemoglobin present in the body helps in the exchange of both these gases. 8. What are the constituents of human blood? ANSWER The main constituents of blood are blood corpuscles, blood platelets and plasma. Blood corpuscles and platelets are the cellular elements in blood while plasma is a fluid. The following chart shows the composition of blood. Notes Prepared by Neil Valentine D Silva DishaEducentre Exhaustive Notes ~4~ The Circulatory System Neutrophils Erythrocytes (RBC) Granulocytes Corpuscles Basophils Leucocytes (WBC) Blood Platelets (Thrombocytes) Plasma Eosinophils Monocytes Agranulocytes Lymphocytes 9. Describe the composition of blood plasma. ANSWER Blood plasma is a light-yellow coloured alkaline liquid. It is composed of the following:a) Water 90 to 92% b) Proteins 7 to 8% c) Inorganic Salts 1% d) Traces of other substances The inorganic salts include sodium chloride and sodium bicarbonate. It also contains the following soluble and insoluble substances:a) Soluble substances: glucose, vitamins, minerals, amino acids, urea. b) Insoluble substances: albumin, globulin, fibrinogen. 10. What is serum? ANSWER Serum is plasma from which fibrinogen has been removed. 11. What is the difference between blood plasma and serum? plasma is the blood excluding the blood corpuscles and platelets. Serum is the blood plasma excluding fibrin. ANSWER Blood 12. Which are the cellular elements in blood? cellular elements present in blood are as follows:a) Red blood corpuscles a.k.a. erythrocytes b) White blood corpuscles a.k.a. leucocytes c) Blood platelets a.k.a. thrombocytes. ANSWER The 13. Write a note on erythrocytes. ANSWER Erythrocytes are red blood corpuscles. They are minute biconcave disc-like structures. They are flat in the centre and thick and rounded at the periphery. They are very small, about 7 in diameter. They have a large surface area due to their biconcave shape. Due to their small size, they can move in blood capillaries in a single file. They contain the red iron-protein pigment haemoglobin. They do not contain nucleus, mitochondria or endoplasmic reticulum. Production: They are produced in the red marrow of long bones such as femur and humerus. The process of their formation is known as erythropoiesis. 14. Write a note on haemoglobin. ANSWER Haemoglobin is an iron-protein complex that is found in the red blood corpuscles (erythrocytes). The iron part of it is called haemin and the protein part is called globin. Notes Prepared by Neil Valentine D Silva DishaEducentre Exhaustive Notes ~5~ The Circulatory System It has the ability to combine with oxygen and form a complex known as oxy-haemoglobin. This complex is responsible for the red colour of blood. Hb + O2 Hb. O2 It can also combine with a small amount of carbon dioxide and form a complex known as carbamino-haemoglobin. Hb + CO2 Hb. CO2 Thus, haemoglobin helps in carrying oxygen and carbon dioxide to their respective destinations. 15. Write a note on leucocytes. are white blood corpuscles. They do not possess haemoglobin, but have a nucleus. They can move by creating false processes known as pseudopodia. This kind of movement is known as amoeboid movement. Using this movement they can pass through capillaries. This is known as diapedesis. They are classified into two granular and agranular. a) Granular leucocytes: They are further divided into neutrophils, eosinophils and basophils. b) Agranular leucocytes: They are further divided into lymphocytes and monocytes. Production: They are produced by a process known as leucopoiesis in the bone marrow, lymph nodes and sometimes in liver and spleen. ANSWER Leucocytes 16. Granular Leucocytes Agranular Leucocytes Describe the three types of granulocytes. three types of granulocytes are neutrophils, eosinophils and basophils. Neutrophils: They stain with neutral dyes. They have granular cytoplasm and nucleus with 3-4 lobes. They are present to an extent of 62%. Eosinophils: They stain dark red with acidic dyes (eosin). They have granular cytoplasm and nucleus with 2 lobes. They are present to an extent of 2-3% and their count increases during allergies. Basophils: They stain blue-black with basic dyes. They have granular cytoplasm and nucleus with 2 lobes. They are present to an extent of 0-4%. ANSWER The (i) (ii) (iii) 17. Discuss the functions of the leucocytes. ANSWER The main function of leucocytes is body defence. (i) Phagocytosis This is the process in which leucocytes engulf bacterial pathogens. This is a defensive protection against harmful germs. (ii) Inflammation When injuries occur or germs invade the body, inflammation occurs. Inflammation causes local heating, redness, swelling and pain. When this happens, leucocytes (especially neutrophils and monocytes) pass through the walls of blood vessels by diapedesis. The damaged cells are also destroyed by phagocytosis and a sticky mass called pus is produced. (iii) Antibodies and Antitoxins Leucocytes produce antibodies that kill or neutralise germs. They also produce antitoxins to neutralise the effect of toxins produced by these germs. This is mainly done by lymphocytes in the white blood corpuscles. (iv) Immunity Lymphocytes present in the leucocytes provide the organism with an ability to resist infections. This is known as immunity. Notes Prepared by Neil Valentine D Silva DishaEducentre Exhaustive Notes 18. ~6~ The Circulatory System Explain in brief how leucocytes protect the body from external germ attacks. occurs in various steps as follows: Phagocytosis: Neutrophils and monocytes engulf the external pathogen and destroy it. Inflammation: The tissues react to the external attack or any injury by getting inflamed. Due to inflammation, the local region gets hotter, redder, swollen and pains. Then, neutrophils and monocytes reach the inflamed region by diapedesis and continue the fight against the pathogens. They destroy the damaged cells by phagocytosis. This causes a sticky mass of dead white blood corpuscles and the damaged cells, which is known as pus. Pus can be removed from the body by making an incision. In this manner, leucocytes destroy invading pathogens and control them from spreading within the body. ANSWER This 19. Describe the thrombocytes (blood platelets). platelets are also known as thrombocytes. They are minute oval or round structures floating in the blood. They are non-nucleated. They are important in blood clotting. Production: They are produced from large cells in the bone marrow known as megakaryocytes. They are fragmented from the megakaryocytes in such a manner that each of them has a complete membrane of its own. They are destroyed in the spleen. ANSWER Blood 20. Describe the process of blood clotting (coagulation). clotting is the process of formation of a hardened mass known as a clot on a site of injury. The main role in blood clotting is played by blood platelets, i.e. thrombocytes. When there is an injury, the damaged tissue cells and the thrombocytes in that region release a substance known as thrombokinase a.k.a. thromboplastin. In recent times, it is also referred to as factor X or Stuart factor. ANSWER Blood release platelets thrombokinase Thrombokinase is an enzyme. With the help of calcium ions, it helps in the conversion of the inactive prothrombin in the blood plasma to the active thrombin. thrombokinase , Ca +2 ions prothrombin thrombin Again, in the presence of calcium ions, thrombin converts fibrinogen of the plasma to fibrin. thrombin , Ca +2 ions fibrinogen fibrin Fibrin is a solid substance that forms microscopic threadlike structures. These are sticky and they form a mesh at the surface of the wound. Blood corpuscles get trapped in the fibrin mesh. Finally, the mesh shrinks and plasma is given out in the form of a clear liquid known as serum. fibrin + corpuscles blood clot The solid mass left behind is known as blood clot. 21. What are blood clotting factors? (extra) are 13 blood clotting factors, which are also known as coagulation factors. Factor I fibrinogen Factor II prothrombin Factor III tissue factor Factor IV calcium Factor V labile factor Factor VI (unassigned) Factor VII stable factor Factor VIII antihaemophilic factor A Factor IX antihaemophilic factor B ANSWER There (i) (ii) (iii) (iv) (v) (vi) (vii) (viii) (ix) Notes Prepared by Neil Valentine D Silva ~7~ DishaEducentre Exhaustive Notes The Circulatory System Stuart-Prower factor antihaemophilic factor C Hageman factor fibrin stabilising factor (x) (xi) (xii) (xiii) Factor X Factor XI Factor XII Factor XIII 22. What happens to the local constituents of blood after blood clotting? contains of corpuscles, platelets and plasma. During the clotting process, platelets are destroyed. Plasma releases fibrin. Fibrin combines with the corpuscles to form the blood clot. Plasma without fibrin oozes out of the wound in the form of serum. ANSWER Blood Blood Platelets Corpuscles Plasma Fibrin 23. Serum Describe the ABO System of classifying blood groups. to the ABO System, blood groups are classified into four types A, B, AB and O. The following is a blood transfusion chart concerning these blood groups:Recipient A B AB O A B AB O People with blood group A can donate blood to people with blood groups A or AB. People with blood group B can donate blood to people with blood groups B or AB. People with blood group O can donate blood to all other blood groups. Hence, blood group O is called as the universal donor. People with blood group AB can receive blood from all other blood groups. Hence, blood group AB is called as the universal recipient. ANSWER According Donor 24. Describe the Rh System of classifying blood groups. blood of most people contains a substance known as Rh factor. Rh stands for rhesus ; the name of a particular species of money in which the factor was first discovered. People who have this factor are said to be Rh-positive while people who do not have this factor are said to be Rh-negative. If Rh-positive blood is transfused into Rh-negative blood, then the recipients develop antibodies for Rh factor (get sensitised) within 2 weeks of transfusion. If more Rh-positive blood is transfused into such antibody-containing Rh-negative blood, then it causes a reaction which may even be fatal. This is similar to the onset of allergies. ANSWER The III. Reasons and Justifications 1. Circulating fluids are essential in our body. ANSWER The circulating fluids blood, tissue fluid and lymph are essential for many processes. The digestive system needs them to digest and absorb nutrients and send them all over the body. The respiratory system needs them for transporting and exchanging gases. Notes Prepared by Neil Valentine D Silva DishaEducentre Exhaustive Notes ~8~ The Circulatory System The excretory system needs them to carry the waste products to the specific excretory organs. The endocrine system needs them to carry hormones to the necessary target organs. 2. White blood corpuscles are known as soldiers of the body. ANSWER White blood corpuscles are leucocytes. When any bacterial pathogen enters the body, they engulf the organism and destroy it by phagocytosis. When there is an invasion of bacteria and inflammation is produced in the body, the leucocytes migrate towards the walls by diapedesis. There they destroy the damaged cells and form pus. Lymphocytes are responsible for producing antibodies and antitoxins. They kill and neutralise germs and the harmful substances produced by them. Lymphocytes also contribute to the immunity of an organism. Hence, they are called soldiers of the human body. 3. Blood is red in colour. ANSWER The red blood corpuscles contain an iron-protein complex known as haemoglobin. When haemoglobin combines with oxygen inhaled by the lungs, it forms another complex known as oxy-haemoglobin. Hb + O2 Hb. O2 This is deep red in colour, and hence makes blood itself red in colour. 4. Blood of crabs is blue. and other crustaceans do not contain haemoglobin in their blood. Instead, they have a copper-protein complex known as haemocyanin. This turns blue in colour when mixed with inhaled oxygen. Hence, crab blood is blue in colour. ANSWER Crabs 5. Blood inside arteries and veins does not clot. ANSWER The various factors needed for blood clotting remain inactive in blood vessels. Blood also contains an anticoagulant called heparin. This prevents the formation of prothrombin under normal conditions, i.e. conditions where there is no injury. Unless and until the blood vessels are damaged due to some reason, the clotting process does not take place. 6. Sodium citrate or sodium oxalate is added to blood stored in blood banks. is done to prevent the clotting of blood. Sodium citrate or sodium oxalate combines with calcium ions present in the blood and make it inactive. In the absence of calcium ions, the clotting process cannot be initiated. ANSWER This 7. Pregnant women are checked for Rh factor in their blood. ANSWER If the mother is Rh-negative and the father is Rh-positive, then the child may be Rh-positive as well. Due to this kind of introduction of Rh factor in the mother, her blood develops antibody for Rhfactor. The first child will be normal. However, if there is a second child, and the child is also Rh-positive, then the antibodies produced during the first pregnancy will cause a reaction. This reaction may even lead to the death of the foetus and abortion. This can be solved if a gap is kept between the two pregnancies. Rh tests can help determine if the mother has Rh antibodies in her blood. IV. Distinctions and Comparisons 1. Blood and Lymph Notes Prepared by Neil Valentine D Silva ~9~ DishaEducentre Exhaustive Notes Blood (i) Blood flows in blood vessels such as arteries, veins and capillaries. (ii) Blood contains plasma, corpuscles and platelets. (iii) Blood contains albumin, globulin and fibrinogen. 2. The Circulatory System Lymph Lymph flows in lymph vessels. Lymph only contains the soluble part of plasma and leucocytes. It does not contain erythrocytes and platelets. Lymph does not contain albumin, globulin or fibrinogen. Red Blood Corpuscles (Erythrocytes) and White Blood Corpuscles (Leucocytes) Red Blood Corpuscles (i) They are nucleated. (ii) They are biconcave in shape. (iii) They possess haemoglobin. (iv) They are always non-granular. (v) They are smaller in size. (vi) Their main function is transport of oxygen. White Blood Corpuscles They are non-nucleated. They do not have a definite shape. They do not possess haemoglobin. They may be granular or agranular. They are larger in size. Their main function is protection of the body. ~ Part B: The Human Heart ~ I. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. Definitions and Explanations Heart Pericardium The double-walled membranous covering present around the heart is known as pericardium. Pericardial Fluid The pericardium is filled with a fluid known as pericardial fluid. It protects the heart by reducing friction during heartbeat and absorbing shocks of mechanical injuries. The two upper chambers of the heart are called atria or auricles. Based on Atria a.k.a. their position, they are called right atrium and left atrium. Auricles The two lower chambers of the heart are called ventricles. Based on their Ventricles position, they are called right ventricle and left ventricle. A muscular partition that divides the heart into two vertical halves is known Septum as the septum. The large blood vessel that brings in deoxygenated blood from the anterior Superior Vena or upper part of the body to the right atrium of the heart is known as the Cava a.k.a. superior vena cava. Precaval The large blood vessel that brings in deoxygenated blood from the posterior Inferior Vena or lower part of the body to the right atrium of the heart is known as the Cava a.k.a. inferior vena cava. Postcaval The tricuspid valve is a valve having three flaps that separates the right Tricuspid Valve atrium from the right ventricle. It is also referred to as right atrio-ventricular valve. Pulmonary Artery The artery that carries deoxygenated blood from the right ventricle to the lungs for oxygenation is known as the pulmonary artery. They are a set of three valves that are located at the point of origin of the Pulmonary Semilunar Valves pulmonary artery from the right ventricle. Pulmonary Veins The four veins that bring back oxygenated blood from the lungs to the left atrium are called as pulmonary veins. The bicuspid valve is a valve having two flaps that separates the left atrium Bicuspid Valve a.k.a. Mitral Valve from the left ventricle. It is also referred to as left atrio-ventricular valve. The largest artery in the body that carries oxygenated blood from the left Aorta ventricle of the heart to the different regions of the body is called as aorta. Notes Prepared by Neil Valentine D Silva DishaEducentre Exhaustive Notes 15. Aortic Semilunar Valves 16. Coronary Arteries 17. Myocardial Infarction 18. Angina Pectoris 19. Systole 20. Diastole 21. Cardiac Cycle II. 1. ~ 10 ~ The Circulatory System The semilunar valves are a set of three valves that are located at the point of origin of the aorta from the left ventricle. The coronary arteries are two arteries that supply blood to the heart muscles. They arise from the base of the aorta. Myocardial infarction is a deadening of an area of the heart caused due to blockage in either of the coronary arteries. It is commonly referred to as heart attack. Angina pectoris is the condition of pain in the heart due to insufficient blood supply via the coronary arteries. The contraction phase of the heartbeat is called as systole. The relaxation phase of the heartbeat is called as diastole. The series of events that occur during one complete heartbeat is called as a cardiac cycle. Questions-Answers What are the components of the human circulatory system? components of the human circulatory system are the heart and the blood vessels. The blood vessels are arteries, veins and capillaries. ANSWER The 2. Where is the heart located? heart is located right in the centre of the thoracic cavity between the two lungs and above the diaphragm. Its narrow end is pointed towards the left side of the body. ANSWER The 3. How is the heart protected? heart is located in the bony rib cage. It also has a double-walled membrane covering it, called pericardium. Between the two layers of this membrane, a fluid called pericardial fluid is present. This fluid protects the heart by:a) Lubricating the heart so as to minimise friction during its pumping action and b) Absorbing shocks due to mechanical injuries. ANSWER The 4. Describe the internal division of the heart. heart is divided by a vertical muscular partition known as septum. Each vertical half is further divided into two chambers each. Thus, the heart has four chambers. The two upper chambers are known as atria or auricles and the two lower chambers are known as ventricles. The tricuspid valve is present between the right atrium and the right ventricle; and the bicuspid valve is present between the left atrium and the left ventricle. Blood is brought into the heart first into the right atrium. This is done by two veins superior vena cava and inferior vena cava. Blood leaves from the right ventricle for the lungs through the pulmonary artery. From the lungs, blood comes back to the heart through the pulmonary veins, which are four in all. From the left ventricle, blood finally leaves the heart through the aorta. ANSWER The 5. Why are coronary arteries important to the wellbeing of the heart? ANSWER The two coronary arteries supply blood the heart. Without these arteries, the heart will not receive energy to perform its pumping action. 6. When does a heart attack occur? ANSWER When the coronary arteries are unable to supply blood to the heart for any reason, then that portion of the heart is unable to perform its pumping job. This portion of the heart may then undergo a deadening, during which no blood reaches the portion. If neglected, this may culminate into a heart attack, i.e. myocardial infarction. Notes Prepared by Neil Valentine D Silva ~ 11 ~ DishaEducentre Exhaustive Notes 7. The Circulatory System List the valves present in the heart and their locations. following is a list of the valves in the heart with their locations:- ANSWER The Valve Location Type of Blood It Allows to Pass Tricuspid Valve or between right atrium and right deoxygenated Right Atrio-ventricular ventricle Valve Pulmonary Semilunar Valves at the opening of the right ventricle deoxygenated into the pulmonary artery Bicuspid Valve or between left atrium and left oxygenated Left Atrio-ventricular Valve ventricle Aortic Semilunar Valves at the opening of the left ventricle oxygenated into the aorta 8. Briefly describe the circulation of blood within the heart. ANSWER The circulation of blood within the different chambers of the heart is described below:- (i) Right Atrium Deoxygenated blood enters the right atrium from:a) The anterior region of the body via the superior vena cava (precaval) and b) The posterior region of the body via the inferior vena cava (postcaval). This causes an expansion of the right atrium. (ii) Right Ventricle When the right atrium contracts, the tricuspid valve is opened. As a result, the blood flows from the right atrium into the right ventricle. When the right ventricle contracts, the blood is forced into the pulmonary artery due to the opening of the pulmonary semilunar valves. The pulmonary artery carries the blood to the lungs for oxygenation. (iii) Left Atrium After oxygenation, four pulmonary veins bring the blood back from the lungs into the left atrium. This makes the left atrium expand. (iv) 9. LeftVentricle When the left atrium contracts, the bicuspid valve is opened. As a result, the blood flows from the left atrium into the left ventricle. When the left ventricle contracts, the oxygenated blood is pushed into the aorta via the aortic semilunar valves. The aorta then carries the oxygenated blood to different parts of the body. Draw a neat, labelled diagram of the human heart showing its various chambers and the path of blood inside it. ANSWER To lung From upper part of the body To body Aorta Superior vena cava To lung Left Atrium Right Atrium LeftVent ricle Notes Prepared by Neil Valentine D Silva Inferior vena cava Right Ventricle From lung From lung DishaEducentre Exhaustive Notes 10. ~ 12 ~ The Circulatory System Write a note on the cardiac cycle. series of events that occur during one complete heartbeat is called as cardiac cycle. The cardiac cycle consists of two phases systole and diastole. ANSWER The (i) (ii) Systole This is the phase during which the heart contracts. During this phase, the atria send blood into the ventricles. The time taken for the atrial systole is 0.1 to 0.16 second and for ventricular systole is 0.3 second. When blood is forced from the atria to the ventricles through the tricuspid and bicuspid valves, they close sharply and this produces a sound Lubb . This is the systolic sound. Diastole This is the phase during which the heart relaxes. During this phase, the ventricles send blood outside the heart. The right ventricle sends the blood to the lungs via the pulmonary artery and the left ventricle sends the blood to the aorta. The time taken for the atrial diastole is 0.7 to 0.76 second and for ventricular diastole is 0.5 to 0.56 second. When blood is forced from the ventricles to the blood vessels through the semilunar valves, they close gently and this produces a sound Dup . This is the diastolic sound. Full Cardiac Cycle In a complete cardiac cycle, the three events occur in succession:Event Occurrence Valve Action a) Atrial systole Sound Average Time Lubb 0.1 s atria contract, atria-ventricular valves open, ventricles relax semilunar valves closed b) Ventricular systole ventricles contract, atria-ventricular valves closed, Dup 0.3 s atria relax semilunar valves open c) Joint diastole all chambers relax all valves closed 0.4 s The average time taken for a full cardiac cycle is around 0.8 seconds in a healthy adult. Thus, the human heart beats 72 times/minute on an average. III. Reasons and Justifications 1. Humans have double circulation of blood in the heart. Notes Prepared by Neil Valentine D Silva DishaEducentre Exhaustive Notes ~ 13 ~ The Circulatory System ANSWER The circulation of blood in the human heart is called as double circulation because blood enters the heart twice in each cardiac cycle. First deoxygenated blood enters the right side of the heart and passes through the right atrium and right ventricle. It then leaves for the lungs via the pulmonary artery for oxygenation. Now this oxygenated blood again enters the left side of the heart and passes through the left atrium and left ventricle. It then leaves for circulation throughout the body via the aorta. Since the blood enters the heart twice during each cardiac cycle, we have double circulation. 2. Smaller animals have a higher heartrate. animals loses more body heat due to their higher surface to volume ratio. Hence, their heart needs to distribute heat faster to various parts of the body and so it beats faster. This increases the heart rate in smaller animals. ANSWER Smaller 3. Infants have a higher heart rate than adults. are at the developmental stage of their life. There are various metabolic processes going on in their bodies due to which substances are produced, developed and eliminated from their bodies at a faster rate than in adults. Also, they have a smaller body size, due to which they lose heat quickly from their bodies. To compensate for all this, the heart has to beat faster to supply blood and body heat more quickly to different parts of the body. For this reason, infants have a higher heart rate than adults. Infants have heart rate of 120 beats/minute while adults have around 72 beats/minute. ANSWER Infants IV. Distinctions and Comparisons 1. Chambers of the Heart Right Atrium upper chamber of right side of heart (ii) carries deoxygenated blood (iii) blood enters from different parts of the body via superior and inferior vena cava (iv) blood leaves to the right ventricle via the tricuspid valve (v) small in size (vi) less muscular (i) 2. Right Ventricle lower chamber of right side of heart carries deoxygenated blood blood enters from the right atrium via the tricuspid valve Left Atrium upper chamber of left side of heart carries oxygenated blood blood enters from the lungs via the pulmonary veins Left Ventricle lower chamber of left side of heart carries oxygenated blood blood enters from the left atrium via the bicuspid valve blood leaves to the lungs via the pulmonary artery large in size more muscular blood leaves to the left ventricle via the bicuspid valve small in size less muscular blood leaves for different parts of the body via the aorta large in size more muscular Systole and Diastole Systole (i) It is the contraction phase of the heart chambers. (ii) Atria send blood to the ventricles to be ejected from ventricles into corresponding blood vessels. (iii) There is maximum pressure in the arteries during this phase. (iv) Atrial systole lasts for 0.1 to 0.16 s and ventricular systole lasts for 0.3 s. Notes Prepared by Neil Valentine D Silva Diastole It is the relaxation phase of the heart chambers. Heart chambers fill with blood. There is minimum pressure in the arteries during this phase. Atrial diastole lasts for 0.7 to 0.76 s and ventricular diastole lasts for 0.5 to 0.56 s. ~ 14 ~ DishaEducentre Exhaustive Notes 3. Atrial Systole and Ventricular Systole (i) (ii) Atrial Systole Atria contract, ventricles relax. Blood is sent from atria to the ventricles. The Circulatory System (iii) Atria-ventricular valves are open, semilunar valves are closed. (iv) It is longer, lasting between 0.7 and 0.76 s. Ventricular Systole Ventricles contract, atria relax. Blood is sent from ventricles to the corresponding blood vessels. Semilunar valves are open, atria-ventricular valves are open. It is shorter, lasting between 0.5 and 0.56 s. ~ Part C: The Blood Vessels ~ I. Definitions and Explanations 1. Artery 2. Vein 3. 4. 5. Arteriole Venule Capillary 6. 7. Vasodilation Vasoconstriction 8. Portal Vein 9. Pulse 10. Blood Pressure 11. Systolic Pressure 12. Diastolic Pressure 13. Hypertension 14. Hypotension 15. Sphygmomanometer An artery is a blood vessel that carries blood away from the heart towards any organ. It has thick muscular walls and a narrow lumen. A vein is a blood vessel that carries blood away from an organ and towards the heart. It has thin muscular walls and a wide lumen. The smallest branch of an artery is known as an arteriole. The smallest united common branch of a vein is known as a venule. A capillary is a very narrow blood vessel (around 8 m in diameter), which acts as a connection between an artery and a vein. The capacity of a capillary to expand (dilate) is called vasodilation. The capacity of a capillary to constrict (contract) is called vasoconstriction. A vein that starts with capillaries and also ends with capillaries is called as a portal vein. The alternate expansion and elastic recoil of the wall of the artery during ventricular systole is called as pulse. The pressure which the blood flowing through the arteries exerts on their walls is known as blood pressure. The blood pressure during the contraction phase of the heart is known as systolic pressure. It is in the range of 100-140 mm of Hg. The blood pressure during the relaxation phase of the heart is known as diastolic pressure. It is in the range of 60-80 mm of Hg. The condition of high blood pressure, i.e. when the systolic pressure is higher than 140 mm of Hg, is known as hypertension. The condition of low blood pressure, i.e. when the diastolic pressure is lower than 60 mm of Hg, is known as hypotension. The instrument used to measure blood pressure is known as sphygmomanometer. II. Questions-Answers 1. Draw a diagram showing the network of capillaries between arteries and veins. ANSWER Notes Prepared by Neil Valentine D Silva ~ 15 ~ DishaEducentre Exhaustive Notes The Circulatory System 2. What are the characteristics of arteries? ANSWER The characteristics of arteries are as follows: They have thick and elastic muscular walls. They have a narrow lumen. They do not have valves. 3. What are the characteristics of veins? characteristics of veins are as follows: They have thin and inelastic muscular walls. They have a wide lumen. They have valves. ANSWER The 4. What are the characteristics of capillaries? ANSWER The characteristics of capillaries are as follows: They have a very narrow diameter, about 8 m. Their wall consists of a single layer of squamous epithelial cells. They have no muscles. 5. What are the functions of capillaries? ANSWER The functions of capillaries are as follows: To allow outward diffusion of oxygen into the intercellular fluid and from there into tissue cells, To allow inward diffusion of carbon dioxide from the intercellular fluid, To allow inward and outward diffusion of substances like glucose, amino acids, urea, hormones, To allow leucocytes to squeeze out through the capillary walls by amoeboid movement. 6. Briefly describe the two paths of circulation of blood in the human body. two paths of blood in the human body are pulmonary circulation and systemic circulation. In one round, blood has to flow through the heart twice. ANSWER The (i) Pulmonary Circulation pulmonary artery (ii) Systemic Circulation aorta 7. pulmonary vein right ventricle lungs left atrium This circulation is maintained by the right side of the heart. It starts in the right ventricle, which expels blood into the pulmonary artery. The pulmonary artery divides into two branches, one going to each lung. It takes the blood to the two lungs for oxygenation. After oxygenation, the four pulmonary veins bring back the blood from the lungs into the left atrium. superior and inferior vena cava left ventricle organs and tissues right atrium This circulation is maintained by the left side of the heart. It starts in the left ventricle, which expels blood into the aorta. The aorta arches back and branches into various arteries, each going to different organs of the body and their tissues. The oxygen in the blood is used up in these organs and tissues. After bring depleted of oxygen, the deoxygenated blood is brought back to the heart. Write a note on the hepatic portal system. Notes Prepared by Neil Valentine D Silva ~ 16 ~ DishaEducentre Exhaustive Notes The Circulatory System ANSWER The two paths of blood in the human body are pulmonary circulation and systemic circulation. In one round, blood has to flow through the heart twice. Pulmonary Circulation (iii) pulmonary artery pulmonary vein right ventricle lungs This circulation is maintained by the right side of the heart. left atrium 8. What is a portal vein? How is it different from other veins? Give an example. ANSWER A portal vein is a vein that starts with capillaries and ends with capillaries. Veins normally bring deoxygenated blood from organs to the heart. However, a portal vein carries blood from one organ to another. The hepatic portal vein which carries blood from the stomach and intestines to the liver is an example. 9. Write a note on the hepatic portal system. hepatic portal vein is a portal vein that brings blood from the stomach and intestine to the liver. Its main role is to process the blood from the digestive system before sending it to the heart. It starts as capillaries formed from the stomach and intestine veins, and ends as capillaries that connect into the liver. Hepatic portal vein processes blood brought from stomach and intestines in the following ways:a) Excess glucose in the blood is converted and stored as glycogen in the liver. b) Excess amino acids are broken down in the liver. c) Harmful substances in the blood are eliminated. d) Bacteria, if any, are destroyed by phagocytosis. e) Excess minerals and vitamins are stored in the liver. Once these processes are done, the blood is ready to be sent back to the heart. The liver does that through the inferior vena cava. ANSWER The 10. Describe human pulse. is the alternate expansion and elastic recoil of the wall of an artery during ventricular systole. Blood is pumped by the left ventricle into the aorta with force as it does not have valves. This causes the aorta to distend. The force is so great that it sends ripples in the entire blood network. This is known as pulse. It is felt at specific places of the body such as the temples, wrist, etc. Counting the pulse is indirectly the counting of the heartbeat. Pulse rate increases when performing physical exercise or under conditions like being emotional, sexually aroused, breathing heavily, etc. ANSWER Pulse 11. Write a short note on blood pressure. (extra) ANSWER Blood pressure is the pressure which the blood flowing through the arteries exerts on their walls. The systolic pressure is the pressure felt during the contraction phase of the heart. It is within the range of 100-140 mm of Hg for a healthy adult. The diastolic pressure is the pressure felt during the relaxation phase of the heart. It is within the range of 60-80 mm of Hg for a healthy adult. Blood pressure is measured by an instrument known as sphygmomanometer. III. 1. Reasons and Justifications The hepatic portal system plays an important role in detoxifying the body. hepatic portal vein brings blood from the stomach and intestines to the liver. Blood from the stomach and intestines contains several harmful by-products of digestion and even bacteria that may be still alive. The hepatic portal vein carries this blood to the liver. Here, the liver detoxifies the harmful substances and destroys the bacteria by phagocytosis. ANSWER The Notes Prepared by Neil Valentine D Silva DishaEducentre Exhaustive Notes ~ 17 ~ The Circulatory System Only purified blood is sent forward to the heart by the liver. 2. The human pulse rate increases when performing exercise. performing exercise, more blood is directed by the heart into the limbs and muscles. Due to this, the heart needs to pump blood at a faster rate. This increases the pulse rate of the individual. ANSWER When 3. Healthy pulse rate decreases as one becomes older. ANSWER As one grows older, the metabolic processes in the body decrease. The heart does not need to pump as much blood into the body as it did at a younger age. Hence, the healthy pulse rate decreases. 4. Counting pulse is the counting of heartbeats. time the heart contracts for pumping of blood, the blood flows with pressure causing a pulse in the arteries. Hence, when we count the pulse, it is the same as counting heartbeats. ANSWER Every IV. Distinctions and Comparisons 1. Arteries and Veins (i) (ii) (iii) (iv) (v) (vi) (vii) Arteries They carry blood from the heart towards the different parts of the body. Except pulmonary artery, all arteries carry oxygenated blood. Their walls are thick and elastic. They have a narrow lumen. They do not have valves in their inner lining. They can constrict or dilate to control blood flow. They are situated deep within the body. (viii) They do not collapse when empty. (ix) The blood flow in them is in jerks and under great pressure. (x) They are branched, and their size decreases with progressive branching. (xi) The smallest artery breaks into arterioles. 2. Arteriole It is the smallest branch of an artery. It is formed by progressive branching of artery. (iii) It branches further to form capillaries. (iv) It carries oxygenated blood. (i) They are situated more superficially in the body. They collapse when empty. The blood flow in them is continuous and with very less pressure. They are branched, and their size increases with progressive branching. The smallest vein arises from venules. Arteriole and Venule (i) (ii) 3. Veins They carry blood from the different parts of the body towards the heart. Except pulmonary veins, all veins carry deoxygenated blood. Their walls are thin and inelastic. They have a wide lumen. They have valves in their inner lining. They cannot constrict or dilate. Venule It is the first branch of the vein. It unites with other venules to form a vein. It is formed by the union of capillaries. It carries deoxygenated blood. Pulmonary Circulation and Systemic Circulation Pulmonary Circulation It is maintained by the right side of the heart. Notes Prepared by Neil Valentine D Silva Systemic Circulation It is maintained by the left side of the heart. ~ 18 ~ DishaEducentre Exhaustive Notes (ii) It is the movement of blood from heart to lungs and back to heart. (iii) During this phase, blood becomes oxygenated. (iv) It begins at the right ventricle and ends at the left atrium. (v) The main blood vessels involved are pulmonary artery and pulmonary veins. 4. The Circulatory System It is the movement of blood from heart to different parts of the body and back to heart. During this phase, blood becomes deoxygenated. It begins at the left ventricle and ends at the right atrium. The main blood vessels involved are aorta and the superior and inferior vena cava. Normal Vein and Portal Vein Normal Vein (i) It begins from capillaries and ends into another vein or at one of the vena cavae. (ii) It carries deoxygenated blood straight to the heart. (iii) Example: veins of head and neck region Portal Vein It begins from capillaries and ends in capillaries. It carries deoxygenated blood to an organ. Example: hepatic portal vein ~ Part D: The Lymphatic System ~ I. Definitions and Explanations 1. Tissue Fluid 2. Lymph 3. 4. Lymphatic Vessels Lymph Nodes 5. Spleen II. As blood flows in the capillaries of the tissues, fluid plasma and some leucocytes oozes out of the porous walls and fills in the space between the cells. This fluid is called as tissue fluid. Lymph is a colourless fluid containing all the constituents of blood except proteins and erythrocytes. The vessels that carry lymph are known as lymphatic vessels. Lymph nodes are regions from where fresh lymph channels arise and ultimately pour the lymph into major anterior veins. The spleen is a large lymphatic organ, reddish brown in colour, and situated in the abdomen behind the stomach and above the left kidney. Questions-Answers 1. How is tissue fluid formed? ANSWER As blood flows in the capillaries of the tissues, fluid plasma and some leucocytes oozes out of the porous walls and fills in the space between the cells. This fluid is called as tissue fluid. It contains proteins, salts and water mixed in the fluid plasma. 2. How is lymph formed? part of the tissue fluid is reabsorbed into the blood vessels. This is mostly salts and water. But most of the proteins remain in the fluid as they cannot be taken up by the blood vessels. This protein-laden filtrate then enters a network of its own, where it mixes up with fat emulsions. This is known as lymph. ANSWER A 3. What does lymph contain? composition of lymph is as follows: Cellular constituents: only leucocytes (mainly lymphocytes) Non-cellular constituents: solids (proteins, fats, carbohydrates, enzymes, antibodies, etc.) to an extent of 6%. ANSWER The 4. Describe the lymphatic system. Notes Prepared by Neil Valentine D Silva DishaEducentre Exhaustive Notes ANSWER The (i) (ii) ~ 19 ~ The Circulatory System lymphatic system consists of lymph, lymph vessels (i.e. lymphatics) and lymph nodes. Lymph Lymph is the remaining portion of tissue fluid after it has been reabsorbed by the blood vessels. It mainly contains proteins and fats along with leucocytes. It is a clear, watery fluid. It is the link between blood and tissue fluid. It contains the following constituents:a) Cellular constituents: only leucocytes (mainly lymphocytes) b) Non-cellular constituents: solids (proteins, fats, carbohydrates, enzymes, antibodies, etc.) to an extent of 6%. Lymph Vessels (Lymphatics) Lymph vessels start out as capillaries in the tissue spaces and form larger ducts. They contain inner valves to prevent backflow of lymphatic fluid. They entwine themselves around muscles of arms and legs. As the muscles move, the fluids move in them. All lymphatic vessels finally move toward the heart and open up into the vena cavae just before they enter the heart. The lymphatic capillaries in the villi of the intestines are called lacteals. Lymph Nodes Lymph nodes are enlargements in the lymph vessels like beads in a string. They are formed of lymphatic tissue separated by partitions. They contain fine branches of lymphatics. They are present in armpits, neck and groin. Tonsils and adenoids are examples of lymphatic tissue. Thymus gland spleen are examples of lymphatic organs. (iii) 5. What are the functions of lymph? following are the functions of lymph:Nutrition Lymph supplies nutrition and oxygen to regions where blood cannot reach. Drainage Lymph drains away excess tissue fluid and metabolites. It returns proteins to the blood from tissue spaces. Absorption Lymphatics absorb fats from the intestine. Defence Lymphocytes and monocytes of the lymph defend the body. Lymphatics remove bacteria from tissues. ANSWER The (i) (ii) (iii) (iv) 6. What is the significance of the lymphatic system? ANSWER The following points illustrate the significance of the lymphatic system: It is an auxiliary system for the return of fluid from tissue to blood. Without this action, the blood volume will reduce as leakage from its capillaries into the surrounding tissues will continue to happen. It returns proteins to blood and maintains the osmotic concentration of blood to facilitate exchange of materials between blood and tissue cells. 7. What is the spleen? Where is it located? ANSWER The spleen is a large lymphatic organ about the size of a clenched fist. It is reddish brown in colour. It is situated in the abdomen behind the stomach and above the left kidney. Notes Prepared by Neil Valentine D Silva DishaEducentre Exhaustive Notes 8. ~ 20 ~ The Circulatory System What are the functions of spleen? following are the functions of spleen:It acts as a blind reservoir. It releases stored blood during emergencies such as haemorrhage, physical or emotional stress or during carbon monoxide poisoning. It produces lymphocytes. It destroys worn out erythrocytes. It produces erythrocytes when the organism is an embryo. ANSWER The III. Distinctions and Comparisons 1. Blood and Lymph Blood (i) It flows in blood vessels. (ii) It contains platelets, erythrocytes, leucocytes and plasma. (iii) It contains albumin, globulin and fibrinogen. Lymph It flows in lymphatic vessels. It contains only soluble parts of plasma and leucocytes; it does not contain erythrocytes. It does not contain albumin, globulin and fibrinogen. DIAGRAM AND APPLICATON BASED QUESTIONS 1. In the figure shown alongside, give the names of all the parts numbered from 1 to 7. above conditions can be interpreted as follows:1. Erythrocytes (red blood corpuscles) 2. Monocyte 3. Plasma 4. Lymphocyte 5. Leucocytes (white blood corpuscles) 6. Basophil 7. Neutrophil 8. Eosinophil 1 ANSWER The 2 3 4 5 6 7 2. (i) (ii) (iii) What do the following conditions imply? 8 Low WBC count (leucopoenia) Low RBC count (anaemia) Low platelet count (thrombocytopoenia) ANSWER The above conditions can be interpreted as follows:(i) Low WBC count (leucopoenia): This refers to a reduction in the body s capacity to fight infections. The person must take additional care for personal and surroundings hygiene. (ii) Low RBC count (anaemia): This implies a reduction in the haemoglobin content; i.e. the oxygencarrying capacity of the person s blood is low. The person will feel dizzy, pale and weak. (iii) Low platelet count (thrombocytopoenia): This refers to a reduction of the person s capacity in healing wounds by blood clotting. The person will also bruise easily and heal slowly. 3. In the highly schematic diagram of the heart shown alongside, name each of the parts in their numbered order. ANSWER The parts are as follows:1. Superior and inferior vena cava Notes Prepared by Neil Valentine D Silva ~ 21 ~ DishaEducentre Exhaustive Notes 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 4. (i) (ii) (iii) (iv) (v) The Circulatory System Pulmonary veins Bicuspid valve Aorta Aortal semilunar valve Left ventricle Right ventricle Pulmonary semilunar valve Pulmonary artery Tricuspid valve Right atrium Left atrium The diagram shows a certain category of blood vessels showing the role of a special structure on their walls. Name the blood vessels shown. What is the structure shown inside the blood vessels? What is the role of these structures? Are these structures present in any other kind of blood vessels? If so, name them. Towards which side of the figure (top or bottom) is the heart located? ANSWER (i) (ii) (iii) (iv) (v) Veins. Valves. The role of these structures is to prevent backflow of blood. Yes, they are present in lymph vessels. The heart is present at the top. 5. The following simplified diagrams refers to the outline plan of the circulation of blood in a mammal. Study the diagram and write the number and the name of the blood vessels in each case as mentioned under. 2 5 3 1 Heart 4 Lungs Liver Gut Kidney 9 7 6 8 (i) (ii) (iii) (iv) (v) Several hours after a meal containing a lot of protein, which vessel will contain the highest concentration of urea? Which vessel would contain the highest concentration of amino acids and glucose after a meal? Which vessel begins and ends in capillaries? In which vessel will the blood carry the most oxyhaemoglobin? Which vessel carries blood from the heart to the lungs? ANSWER (i) (ii) (iii) 7 hepatic vein (the vein that carries deoxygenated blood from liver to inferior vena cava) 4 hepatic portal vein (the vein that carries blood from stomach and small intestine to liver) 4 hepatic portal vein Notes Prepared by Neil Valentine D Silva DishaEducentre Exhaustive Notes ~ 22 ~ (iv) (v) 1 pulmonary vein 9 pulmonary artery 6. Given is a simple diagram of the circulation of blood in a mammal showing the main blood vessels, the heart, lungs and body tissues. The blood vessel labelled 6 contains deoxygenated blood and the valve leading to it has three semilunar pockets. Name the blood vessels or organs marked by the numbers 1 to 8. ANSWER 1. 2. 3. 4. 5. 6. 7. 8. 7. Body tissues Superior and inferior vena cava Aorta Right ventricle Left auricle Pulmonary artery Pulmonary vein Lungs Write the names of all the numbered parts in the figure shown alongside. Assume that the blood is moving from the blood vessel on the left to the one on the right. Also answer the following questions:Which side contains oxygenated blood? What tissue is the wall of 6 made of? What is the name of the process by which the liquid component of blood oozes out from 6 to 5? The heart supplies blood to which vessel 1 or 4? (i) (ii) (iii) (iv) ANSWER 1. 2. 3. 4. 5. 6. (i) (ii) (iii) (iv) Artery Arteriole Venule Vein Tissue cells Capillaries The left side vessel contains oxygenated blood. Squamous epithelium Diapedesis Heart supplies blood to blood vessel 1, i.e. artery. Notes Prepared by Neil Valentine D Silva The Circulatory System ~ 23 ~ DishaEducentre Exhaustive Notes The Circulatory System SUMMARIES 1. Properties of Erythrocytes, Leucocytes and Thrombocytes (i) (ii) Life span Number Erythrocytes (RBC) 120 days 4 to 5 million/mm3 Leucocytes (WBC) few hours to few days 5,000 to 10,000/mm3 (iii) (iv) (v) Shape Diameter Formation biconcave discs 7-8 in red bone marrow irregular (amoeboid) 8-20 in red bone marrow and lymph nodes liver and bacteria (pus) nucleated absent moves independently (amoeboid movement) phagocytosis, production of antibodies and antitoxins (vi) (vii) (viii) (ix) Destruction Nucleus Pigments Movement (x) Functions liver and spleen non-nucleated haemoglobin moves due to force from heartbeat carries oxygen and carbon dioxide 2. Process of Phagocytosis and Inflammation Neutrophils and monocytes engulf invading bacteria and destroy it by phagocytosis. Neutrophils and monocytes engulf remaining pathogens and destroy dead cells by phagocytosis. 3. Damaged tissues cause inflammation of affected area. It becomes hot, red, swollen and pains. Dead cells and leucocytes form a white sticky mass known as pus. Process of Blood Clotting Notes Prepared by Neil Valentine D Silva Thrombocytes (Platelets) 5-9 days 2,50,000 to 4,00,000/mm3 round or oval 2-4 in bone marrow disintegration non-nucleated absent moves due to force from heart blood clotting Neutrophils and monocytes move towards affected area by diapedesis. ~ 24 ~ DishaEducentre Exhaustive Notes The Circulatory System Injury occurs. With help of Ca ions, thrombokinase converts prothrombin to thrombin. Fibrin forms a threadlike mesh over the wound. 4. Local platelets and damaged tissue cells release thrombokinase. Mesh also contains blood cells and oozes clear plasma known as serum. With the help of Ca ions, thrombin converts fibrinogen to fibrin. Mesh hardens and becomes blood clot. Schematic Representation of Human Blood Circulation within Heart From upper part of body Through superior vena cava From upper part of body Right Atrium Left Atrium Pulmonary veins From lungs Through inferior vena cava tricuspid valve To lungs Pulmonary artery Right Ventricle Notes Prepared by Neil Valentine D Silva bicuspid valve Left Ventricle Aorta To body

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Additional Info : ICSE Biology Notes by Bhomik Acharya (bhomik1018)
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