Cardiovascular system at rest/cardiac cycle Flashcards
What are the 4 heart chambers?
Right atrium. Left atrium. Right ventricle. Left ventricle
What are the 4 heart valves?
Tricuspid valve. Bicuspid valve. Pulmonary semilunar valve. Aortic semilunar valve.
What are the two blood vessels that attach to the heart?
Vena cava. Pulmonary artery. Pulmonary vein. Aorta.
What are the 4 features of the conduction system?
SA node. AV node. Bundles of HIS. Purkinje fibres.
How does the blood flow through the heart on the right hand side?
Vena cava - right atrium - tricuspid valve - right ventricle - pulmonary semilunar valve - pulmonary artery - lungs
How does the blood flow through the heart on the left hand side?
Pulmonary veins - left atrium - bicuspid valves - left ventricle - aortic semilunar valve - aorta - body tissues
What is the conduction system?
Specialised bundles of of tissue that transmit the electrical impulse through the heart causing a coordinated contraction
What are the 4 features of the conduction system?
SA Node, AV Node, Bundles of His, Purkinje Fibres
Describe the SA Node
Found in the wall of right atrium. sends impulse across both atria causing atrial systole.
Describe the AV Node
In the middle wall of the heart. Between atria and ventricles. Receives impulse from SA node, delays it for a moment to allow for atrial systole to finish and sends it down the bundles of his.
Describe bundles of his
in the middle wall of the heart. Transmits impulse to the bottom of the right and left side of heart
Describe purkinje fibres
in the walls of the ventricles. Causes impulse to penetrate into ventricle walls causing ventricular systole.
What is the cardiac cycle?
all the events associated with the flow of blood through the heart during one complete heartbeat.
1- atrial diastole
2- atrial systole
3- ventricular diastole
4- ventricular systole
controlled by conduction system to produce highly coordinated contractions of the heart.
What is systole?
the heart working. The contraction phase of the heart chamber when it is pumping out blood.
1- atrial systole - blood pumped into ventricles.
2- ventricular systole - blood pumped in to pulmonary artery and aorta.
What is diastole?
the heart relaxing. The relaxation phase of the heart chamber when it is receiving blood.
1- atrial diastole - blood entering the atria via vena cava and pulmonary vein.
2- ventricular diastole- blood entering the ventricles from the atria.
Describe atrial diastole in relation to the cardiac cycle
No electrical impulse. Atria fills with blood from vena cava and pulmonary vein. AV valves closes. Atrial pressure rises above ventricular pressure. Blood start to pass passively into ventricles.
Describe atrial systole in relation to the cardiac cycle
SA node fires electrical impulses across atria. Atria contract. AV valves forced open. Remaining blood is pumped into ventricles. Semilunar valves close.
Describe ventricular diastole in relation to the cardiac cycle.
Impulses received by the AV node. Delayed for a moment to allow atria systole to complete. AV valve closes. AV node sends impulses down the right and left bundles of his into the purkinje fibres.
Describe ventricular systole in relation to the cardiac cycle
Ventricles contract from the bottom upwards. Semilunar valves forced open. Blood is pumped out of ventricles into pulmonary artery and aorta.
What is heart rate (HR)?
the number of times the heart beats per minute. BPM
What is the average value of HR at rest?
70 BPM
What is the value of HR for an endurance athlete?
50 BPM
How do you work out max HR?
200bpm - age
What is bradycardia?
Having a resting HR lower than 60bpm
