Cardiac cycle and its control 4.5 / 5 based on 4 ratings ? BiologyHuman, animal and plant physiologyASWJEC Created by: sophiee96Created on: 19-03-13 20:05 What is the cardiac muscle? Myogenic 1 of 30 What does myogenic mean? That it's contraction is generated within itself 2 of 30 Is external stimulus needed to stimulate heart contractions? No 3 of 30 What does the cardiac muscle act as? A pacemaker 4 of 30 What causes the atria to contract simultaneously? A wave of contraction from the sino-atrial node 5 of 30 What happens to the blood pressure in the atria when they contract? It rises above that in the ventricles 6 of 30 What happens when the pressure in the atria rises above that of the ventricles? (and via which valves?) Blood is forced into the ventricles via the atrioventricular valves 7 of 30 What happens during atrial systole? Blood is forced from the atria into the ventricles via the atrioventricular valves 8 of 30 What happens when the wave of contraction reaches the atrioventricular node? There is a slight delay before impulses are transmitted to the ventricles 9 of 30 Impulses are transmitted to the ventricles through what? The Purkinje fibres 10 of 30 What do the Purkinje fibres form in the septum? The bundle of His 11 of 30 What happens after the wave of contraction is transmitted to the ventricles? It spreads out across the ventricles and they contract simultaneously 12 of 30 Which valve closes when the blood pressure in the ventricles rises? The atrioventricular 13 of 30 What does the closure of a valve prevent? The backflow of blood 14 of 30 What happens when pressure in the ventricles rises above pressure in the arteries? (via which valves?) Blood is forced out of the heart into the aorta via the semi-lunar valves 15 of 30 What happens during ventricular systole? Blood flows from the ventricles into the aorta 16 of 30 What happens during diastole? The ventricles relax 17 of 30 What happens to the pressure in the ventricles when they relax? It falls below the pressure in the arteries 18 of 30 Which valves close during diastole? The semi lunar valves 19 of 30 What does systole mean? Contraction 20 of 30 What does diastole mean? Relaxation 21 of 30 Which valve closes and which opens during ventricular systole? Atrioventricular valve closes and semi-lunar valve opens 22 of 30 Which stage immediately follows ventricular systole? Diastole 23 of 30 What is the name given to the pacemaker structure in the wall of the right atrium? Sinoatrial node 24 of 30 What is the name of the second pacemaker? Atrioventricular node 25 of 30 What do mammals and birds have? Four chambered heart and double circulation 26 of 30 What happens to blood once it has entered the heart in a double circulation? It is pumped to the lungs, exchanges carbon dioxide for oxygen, returns to the heart and then is pumped around the body 27 of 30 Why is a double circulatory system important for birds and mammals? They have a high metabolic rate 28 of 30 What is the benefit of having a double circulatory system? It maintains a high blood pressure and prevents mixing of oxygenated and deoxygenated blood 29 of 30 What is the benefit of blood being pumped at a high pressure? Faster flow rate in the systematic and pulmonary circulations 30 of 30
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