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Class: Name: ( ) Date: 14 Transport in humans 14.1 Why do we need a transport system? (Book 2, p.156) To survive, cells must have a continuous supply of oxygen, nutrients and other useful substances, and also a continuous removal of metabolic waste, e.g. carbon dioxide. Therefore, a transport system is needed for multicellular organisms, such as humans. (1) Transport is the process of moving substances from one place to another within an organism. In humans, transport is provided by the (2) and the (3) lymphatic circulatory system system (循環系統) (淋巴系統). The human circulatory system (Book 2, p.156) The human circulatory system consists of (5) (4) heart network of (6) blood blood (血液) (心臟) vessels (血管) Note: For unicellular organisms, diffusion alone is sufficient for the transport of substances into or out of the cells. 58 Certificate Biology - New Mastering Basic Concepts Oxford University Press 2005 Class: Name: ( ) Date: 14.2 What makes up blood? (Book 2, p.157) Blood is a fluid (1) tissue which is made up of blood cells and plasma (血漿). Composition of blood It can be separated into two layers by a centrifuge (離心機). The top watery yellow layer is the (2) plasma (3) blood while the lower dark red layer consists of all the cells . blood plasma centrifuge blood cells Centrifugation of blood Go To … Practical 14.1 Examination of a blood smear (Student’s Book 2 p.157; Activity Book 2 p.109) Note: A centrifuge is commonly used in the laboratory to separate compounds on the basis of their molecular weight. It works by swinging the samples in a circular motion at high speed. Certificate Biology - New Mastering Basic Concepts Oxford University Press 2005 59 Class: Name: ( ) Date: Different types of blood cells (Book 2, p.158) Red blood cells (Book 2, p.158) Red blood cells are of (1) disc biconcave whole shape. They contain (2) haemoglobin molecules to section carry oxygen from the lungs to all parts of the body. Red blood cell Mature red blood cells do not have any nuclei. White blood cells (Book 2, p.158) White blood cells are (3) They are important in protecting us from (4) irregular in shape. diseases . round nucleus lobed nucleus Lymphocyte (淋巴細胞) Phagocyte (吞噬細胞) White blood cells Blood platelets (Book 2, p.158) Blood platelets are very small pieces of broken cells. They are (5) They help in (6) entry of (7) blood pathogens clotting irregular in shape. to stop bleeding and to prevent the . Blood platelets do not have nuclei as they are not cells. Blood platelets 60 Certificate Biology - New Mastering Basic Concepts Oxford University Press 2005 Class: Name: ( ) Date: Substances transported in blood (Book 2, p.159) (1) Oxygen , carbon dioxide, nutrients, urea, (2) (3) antibodies hormones , heat and are transported by blood. Substances transported in blood Go To … Practical 14.2 Detection of the presence of glucose in plasma (Student’s Book 2 p.160; Activity Book 2 p.111) Section concept diagram (Student’s Book 2 p.161) Quick check (Student’s Book 2 p.161) 14.3 What are the types of blood vessels? (Book 2, p.162) The blood vessels are divided into from aorta three types: 1 (4) Arteries artery (動脈) which carry blood from the heart to the tissues 2 (5) capillaries Veins (靜脈) which carry blood from the tissues back to the heart 3 (6) Capillaries vein (微血管) which connect the arteries to the veins to vena cava Blood vessels Certificate Biology - New Mastering Basic Concepts Oxford University Press 2005 61 Class: Name: ( ) The relationship between different types of blood vessels: aorta branches into arteries (大動脈) branch into (動脈) arterioles branch into a network of (小動脈) pumps blood into heart capillaries (exchange of materials) drain blood into venae cavae (大靜脈) join to form Date: veins (靜脈) venules join to form (小靜脈) join to form A high blood pressure is developed in the arteries due to the pumping action of the heart. When blood passes through the arterioles and reaches the capillaries, there is a great drop of blood pressure due to the larger total cross-sectional area of the capillaries. The blood pressure is even lower when it reaches the venules and the veins due to the friction of the capillary walls. Changes in blood pressure along different blood vessels Arteries (Book 2, p.163) Arteries carry (1) oxygenated blood (含氧血) away from the heart (except in the pulmonary artery). They have a small lumen and a thick wall to withstand high blood pressure. Cross-section of an artery Blood in the arteries is moved by the pressure set up by the (2) pumping action of the heart. 62 Certificate Biology - New Mastering Basic Concepts Oxford University Press 2005 Class: Name: ( ) Date: Veins (Book 2, p.163) Veins carry (1) deoxygenated blood (缺氧血) to the heart (except in the pulmonary vein). They have a large lumen to reduce resistance to blood flow. Cross-section of a vein Blood in the veins is moved mainly by the pressure on the veins from the contraction of (2) body (3) Valves muscles . are present to prevent the backflow of blood and to ensure that the blood only flows towards the heart. How muscle contraction helps blood flow in veins Capillaries (Book 2, p.164) Capillaries allow the (4) exchange of very small lumen materials between the blood and the body cells. (5) Branching of capillaries greatly increases the surface area for diffusion one layer of cells of materials. Capillaries have large total cross-sectional area which slows down the blood flow and Cross-section of a capillary allows a longer time for exchange of materials. The one-cell thick capillary wall provides a short distance for rapid diffusion of materials. Certificate Biology - New Mastering Basic Concepts Oxford University Press 2005 63 Class: Name: ( ) Date: Go To … Practical 14.3 Examination of the transverse sections of an artery and a vein (Student’s Book 2 p.164; Activity Book 2 p.113) Practical 14.4 Examination of the capillary flow in a fish tail fin (Student’s Book 2 p.165; Activity Book 2 p.114) Quick check (Student’s Book 2 p.166) 14.4 What is the structure of a heart and how does it function? (Book 2, p.167) The heart is located inside the thorax between the two lungs. It is protected by the (1) pericardium (圍心膜). The heart is made up of (2) cardiac muscle (心肌) which contracts and relaxes continuously to pump blood throughout the body. The (3) coronary cardiac muscle while the (4) arteries coronary (冠狀動脈) supply oxygen and nutrients to the veins (冠狀靜脈) carry carbon dioxide and other waste away from the cardiac muscle. External structure of a heart 64 Certificate Biology - New Mastering Basic Concepts Oxford University Press 2005 Class: Name: ( ) Date: The structure of a heart (Book 2, p.168) A F B G C H D I E J Vertical section of a heart Structure (1) A Description Pulmonary artery (2) B Superior vena (3) Carries blood from the right ventricle to the lungs Carries blood from the head and the arms to the right auricle Located at the base of the aorta and the pulmonary artery Prevent the backflow of blood into the ventricles Carries blood from the legs and the abdomen to the right auricle cava Semi-lunar valves (半月瓣) C D (4) vena (5) E Inferior cava Tricuspid valve (三尖瓣) Has three flaps Prevents the backflow of blood from the right ventricle to the right auricle Certificate Biology - New Mastering Basic Concepts Oxford University Press 2005 65 Class: Name: ( Structure (1) Aorta (2) Pulmonary veins (3) Bicuspid H valve (4) Carries blood from the left ventricle to the whole body (except the lungs) Carry blood from the lungs to the left auricle (二尖瓣) (腱索) Prevents the bicuspid and tricuspid valves from turning inside out when the ventricles pump blood out of the heart Prevents the mixing of oxygenated and deoxygenated blood I (5) Septum (隔) J The heart consists of the left and right (6) (7) ventricles auricles (心耳) and the left and right (心室). They auricles receive blood at low pressure from the venae cavae and the pulmonary veins, and they have a (8) Has two flaps Prevents the backflow of blood from the left ventricle to the left auricle Heart tendon Date: Description F G ) thin wall. Since ventricles contract strongly to pump blood out of the heart under high pressure, they have a (9) thicker The (10) left whereas the (11) wall than auricles. ventricle pumps blood to all parts of the body (except the lungs) right ventricle pumps blood only in a short distance to the lungs. Therefore, the wall of left ventricle is (12) thicker than that of the right ventricle. Go To … Practical 14.5 Dissection and examination of a pig heart (Student’s Book 2 p.169; Activity Book 2 p.116) 66 Certificate Biology - New Mastering Basic Concepts Oxford University Press 2005 Class: Name: ( ) Date: Cardiac cycle (Book 2, p.170) The (1) cardiac cycle one heartbeat. It involves a single (2) (心搏週期) contraction is the sequence of events that take place in and (3) relaxation of the cardiac muscle to pump blood around the body. 1 Blood flows from the venae cavae and pulmonary veins into the relaxed right and left auricles respectively. As the auricles contract, blood inside is pushed into the two ventricles. The auricles then relax. 2 When the ventricles contract, blood is pumped into the pulmonary artery and the aorta respectively. The ventricles then relax. 3 When the auricles and ventricles are in a relaxed state, blood from the venae cavae and pulmonary veins flow into the auricles again. This completes one cardiac cycle. Certificate Biology - New Mastering Basic Concepts Oxford University Press 2005 67 Class: Name: ( The coronary arteries and coronary heart disease ) Date: (Book 2, p.171) Fatty substances deposit on the inner wall of the coronary arteries. This narrows the arteries and slows down the blood flow. (1) Coronary heart disease (冠心病) and eventually heart attack will result. Cholesterol plaque blocking the coronary arteries may lead to a heart attack Diets high in (2) fats animal and (3) cholesterol , smoking, stress and lack of exercise are causes of coronary heart disease. A lot of dim-sum are high in cholesterol Go To … STS connection 14.1 Relationship between diet, lifestyle and the incidence of coronary heart disease, stroke and high blood pressure (Student’s Book 2 p.172; Activity Book 2 p.122) Quick check (Student’s Book 2 p.173) 68 Certificate Biology - New Mastering Basic Concepts Oxford University Press 2005 Class: Name: ( ) Date: 14.5 How is blood circulated in the body? (Book 2, p.174) A complete blood circulation consists of both (1) (體循環) and (2) pulmonary systemic circulation circulation (肺循環). Since blood passes through the heart twice in one complete circulation, this type of circulation is called a (3) double circulation (雙循環). Pulmonary circulation (Book 2, p.174) The right ventricle pumps deoxygenated blood through the (4) into the lungs. The oxygenated blood flows through the (5) pulmonary pulmonary artery veins to the left auricle. Systemic circulation (Book 2, p.174) Oxygenated blood flows from the left auricle to the left ventricle, which pumps blood through the (6) aorta to all parts of the body except the lungs. In the capillary beds, materials are exchanged. The deoxygenated blood returns to the right auricle through the (7) cavae venae . Key: pulmonary circulation systemic circulation L.A. = left auricle L.V. = left ventricle R.A. = right auricle R.V. = right ventricle The human circulation plan Certificate Biology - New Mastering Basic Concepts Oxford University Press 2005 69 Class: Name: ( ) Date: 14.6 How are materials exchanged between blood and the body cells? (Book 2, p.176) plasma in capillary Exchange of materials between blood and body cells takes place at the (1) capillaries only. Due to the blood pressure inside the capillaries and the concentration difference, useful materials are forced out of the blood into the tissue fluid and then diffuse into Exchange of materials between blood and body cells the body cells. tissue fluid Waste from the body cells diffuses from the body cells into the tissue fluid and then passes through the capillaries into the blood. E Formation of tissue fluid (Book 2, p.176) At the arterial end of the capillary beds, the blood pressure inside capillaries is (2) higher than the pressure of the tissue fluid. Some materials are forced out of the capillaries to form the tissue fluid. (3) Tissue fluid serves as an important bridge for the exchange of materials between capillaries and body cells. Plasma proteins, (4) red blood cells and blood platelets in blood are too large to be forced out through the capillary wall. Yet, (5) blood cells white can squeeze between the cells of capillary walls and enter the tissue fluid. The composition of tissue fluid is similar to plasma, except that it has no (6) plasma proteins . At the venous end of the capillary beds, the blood pressure is (7) lower than that of the tissue fluid. Some tissue fluid returns to the capillaries while some is drained into the lymph vessels. 70 Certificate Biology - New Mastering Basic Concepts Oxford University Press 2005 Class: Name: ( ) Date: lymph vessel lymphatic capillary red blood cell arteriole venule body cell direction of blood flow higher pressure at arterial end lower pressure at venous end tissue fluid Key: plasma forced out of the capillary to form tissue fluid tissue fluid returned to the capillary tissue fluid drained into the lymph vessel Formation of tissue fluid in the capillary bed Go To … Quick check (Student’s Book 2 p.177) E 14.7 What is the lymphatic system? (Book 2, p.178) The lymphatic system consists of (1) (2) lymph lymph vessels with lymph nodes and the inside. Lymphatic system Certificate Biology - New Mastering Basic Concepts Oxford University Press 2005 71 Class: Name: ( 1 Lymph vessels (Book 2, p.178) (1) Lymph capillaries ) Date: are blind-ended vessels present in the capillary beds. They join to form lymph vessels, which return the tissue fluid to the blood as lymph. Lymph is moved along the lymph vessels: 1 By contraction of (2) 2 (3) Valves body muscles surrounding them. in the lymph vessels prevent backflow of the lymph. Lymph vessel 2 Lymph nodes (Book 2, p.178) (4) Lymph nodes are swellings at intervals along the lymph vessels. Many white blood cells accumulate there to kill pathogens. Lymph is filtered through the lymph nodes before it is returned to the circulatory system. E Functions of the lymphatic system (Book 2, p.179) 1 Transport of tissue fluid back into the blood. 2 Transport of absorbed (5) 3 As a site for (6) body fats from lacteals in intestinal villi into the blood. defence . Go To … Section concept diagram (Student’s Book 2 p.180) Quick check (Student’s Book 2 p.180) Review (Student’s Book 2 p.181) Summary concept diagram (Student’s Book 2 p.182) 72 Certificate Biology - New Mastering Basic Concepts Oxford University Press 2005 Class: Name: ( ) Date: Practice question A heart is cut across the left and the right auricles. The diagram below shows the top view from the cut end of one of the halves. a Name structures A, D, E and F. (4 marks) A: Tricuspid valve, D: Septum, E: Bicuspid valve, F: Semi-lunar valve. (1m x 4) b The blood flowing through blood vessel B has a higher concentration of oxygen than the blood flowing through blood vessel C. Identify the two blood vessels. (2 marks) B: Aorta, C: Pulmonary artery. (1m x 2) c When the ventricles contract, what will happen to i structure E? (1 mark) Structure E will close. (1m) ii structure F? (1 mark) Structure F will open. (1m) ii the blood in the ventricles? (1 mark) The blood in the ventricles will be pumped into blood vessels B (aorta) and C (pulmonary artery). (1m) d How will the function of the heart be affected if structure E cannot close completely? (2 marks) There will be a backflow of blood into the left auricle. (1m) The heart will become less efficient in pumping blood to other parts of the body. (1m) Total: 11 marks - END - Certificate Biology - New Mastering Basic Concepts Oxford University Press 2005 73