Structure and function of the cardiovascular system Flashcards
What is the path of blood through the left side of the heart
Blood oxygenated at the lungs and brought back to heart via pulmonary vein. Moves from left atrium through bicuspid valve into left ventricle. Forced out left side into aorta, which carries blood to muscles and organs
What is the path of blood through the right side of the heart
Deoxygenated blood from muscles enters right atrium via vena cava. Moves from right atrium through tricuspid valve to right ventricle. Forced out of right side into pulmonary artery, where blood is carried to lungs for re oxygenation
What is the cardiac cycle
Process of cardiac muscle contractions and blood moving through chambers. (1 cycle represents 1 heart beat)
What is the approx time taken for a cardiac cycle
0.8 secs
What are the 3 stages of the cardiac cycle
- Diastole
- Atrial systole
- Ventricular systole
What are the durations for the 3 stages of a cardiac cycle
- Diastole - 0.4 secs
- Atrial systole - 0.1 secs
- Ventricular systole - 0.3 secs
What is the diastole stage of the cardiac cycle
Heart relaxes and fills with blood, so pressure in atria increase and valves open. Blood passively enters ventricles
What is the name for the volume of blood after the filling stage of diastole
End diastolic volume
What is the atrial systole stage of the cardiac cycle
Atria contract, forcing blood into ventricles
What is the ventricular systole stage of the cardiac cycle
Ventricles contract, increasing pressure to close AV valves to prevent atrial backflow. Increasing pressure forces blood out of ventricles (SV). Tri/bicuspid valves remain shut and aortic and pulmonary valves shut to prevent backflow
What is the name for the volume of blood left after ventricular systole
End systolic volume
What does it mean for the heart to be myogenic
Generates it’s own impulse
How many stages are there in the conduction system
6
What is the first stage of the conduction system
SA node located in right atrium wall emits impulse through walls, causing depolarization (heart rate)
What is the second stage of the conduction system
Impulse spreads to adjacent interconnecting fibres of left atrium
What is the third stage of the conduction system
Impulse moves to AV nodes
What is the fourth stage of the conduction system
Impulse (action potential) is passed to bundle of His, with a delay of 0.1 secs to allow full atrial contraction
What is the fifth stage of the conduction system
Impulse moves down bundle of his to apex
What is the sixth stage of the conduction system
Impulse spreads to purkinje fibres causing ventricular systole
