Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Electrocardiography wikipedia , lookup
Management of acute coronary syndrome wikipedia , lookup
Heart failure wikipedia , lookup
Arrhythmogenic right ventricular dysplasia wikipedia , lookup
Artificial heart valve wikipedia , lookup
Coronary artery disease wikipedia , lookup
Quantium Medical Cardiac Output wikipedia , lookup
Antihypertensive drug wikipedia , lookup
Lutembacher's syndrome wikipedia , lookup
Atrial septal defect wikipedia , lookup
Dextro-Transposition of the great arteries wikipedia , lookup
Hind Leys Biology F211 Transport in animals 5.2 The mammalian heart Objectives Describe the external and internal structure of the mammalian heart. Explain the differences in thickness of the walls of the different chambers of the heart in terms of their functions. The heart The mammalian heart is a muscular double pump, It is divided into two sides; the right pumps deoxygenated blood to the lungs, and the left pumps oxygenated blood to the rest of the body. Both sides of the heart contract putting the blood under pressure to Aorta force it along arteries. Pulmonary artery Vena cava Left atrium Left ventricle Pulmonary vein Figure 1 External features of the heart Right atrium Coronary artery Right ventricle Vena cava The heart sits slightly off-centre to the left of the chest cavity, with the atria in the middle of the cavity. The lower, main part of the heart is the firm muscle of the ventricles. Above the ventricles are two thin-walled atria. Coronary arteries lie over the surface of the heart, carrying oxygenated blood to the heart muscle itself. Constriction of these can have severe consequences, restricting the delivery of oxygen and nutrients to the heart muscle. This may cause angina or a heart attack, a myocardial infarction. Examiner tip An easy way to remember which Inside the heart chamber is attached to The heart is divided into four chambers; two upper which vessel is to atria which receive blood from the major veins. Deoxygenated remember that A and V blood flows into the right atrium via the vena cava. always go together. Oxygenated blood flows via the pulmonary vein into the left atrium. Atria link to Veins, and 1 Ventricles link to Arteries. Hind Leys Biology F211 Transport in animals 5.2 Tendinous cords Septum Figure 2 The internal structure of the heart http://www.kscience.co.uk/animations/heart_labelling.htm There are atrioventricular valves between each atrium and its ventricle. These are thin flaps of tissue arranged in a cup shape. As the venticles contract the valves fill with blood and close, preventing blood flowing back into the atria. The valves are attached to the inside of the ventricles by tendinous cords which prevent them from turning inside out. At the base of the major arteries, where they exit the heart, are valves called semi-lunar valves. These prevent blood returning to the heart as the ventricles relax. Examiner tip When trying to label a diagram of the heart, remember that right is longer than left! Every structure on the right side of the heart is a longer word than its corresponding feature on the left side of the heart. This also includes the colours used to indicate oxygenated and deoxygenated blood. And indeed the words oxygenated and deoxygenated. http://www.youtube.com/watch?v=H04d3rJCLCE&feature=related Structure related to function Each chamber of the heart contracts to increase the pressure of the blood. The higher the pressure, the further the blood will be pushed. Each chamber has a structure which is adapted to its function in circulating the blood. 2 Hind Leys Biology Chamber Atria Structure Thin walled F211 Transport in animals 5.2 Function To push blood into the ventricles. No need to create much pressure Right ventricle Left ventricle Thicker than atria, but Pumps blood to lungs, short distance. Also not as thick as those of risk of damage to lung capillaries if left ventricle. pressure too high. 2-3x thicker than right Blood needs to be pumped at high ventricle. pressure out of heart into aorta and around rest of body, avoiding resistance of systemic circulation. Table 1 Comparison of structure and function of heart chambers 1. What is the name of the blood vessel which supplies the heart muscle with oxygenated blood? 2. State whether the blood in each of the following structures is oxygenated or deoxygenated; a) vena cava b) pulmonary artery c) left atrium 3. List the correct sequence of four main blood vessels and four heart chambers that a red blood cell passes through on its journey from the lungs, through the heart and body and back to the lungs. 4. Suggest why it is important to prevent mixing of the blood in the two sides of the heart, and name a condition in new-borns which enables this to occur. 5. Describe the function of the atrioventricular valves. 6. Describe the role of the tendinous cords, or ’heart strings’. 7. Explain why the wall of the left ventricle needs to be much thicker than that of the right ventricle. 8. Explain the danger of the pressure created by the right ventricle being too high. This work can be reinforced using pages 65-66 of your textbook. 3