Cardiovascular System Flashcards
Briefly outline the cardiovascular system
Vena Cavae –> Right Atrium –> Right AV Valve –> Right Ventricle –> Pulmonary SL Valve –> Pulmonary Arteries –> Lungs –> Pulmonary Veins –> Left Atrium –> Left AV Valve –> Left Ventricle –> Aortic SL Valve –> Aorta –> Body –> Vena Cavae
What are the names of the Atrioventricular valves and where are they situated?
- Tricuspid (right AV) Valve
right atrium –> right ventricle - Bicuspid (left AV) (mitral) Valve
left atrium –? left ventricle
What do tricuspid and bicuspid mean?
Tricuspid = 3 cusps of endocardium Bicuspid = 2 cusps of endocardium
What are the names of the Semilunar valves and where are they situated?
- Pulmonary valve
right ventricle –> pulmonary artery - Aortic valve
left ventricle –> aorta
Which blood vessels supply the heart with blood?
Coronary arteries and veins
Describe the position of the heart
- In the mediastinum (between lungs in the thoracic cavity)
- Between ribs 2 and 6
What is the base of the heart called and what is significant about this area?
Apex, where the heartbeat is at maximum intensity
What is the point of maximal intensity?
The point at which the cardiac impulse can be best palpated against the chest wall
What structure divides the two halves of the heart?
Septum
What is the name of the heart covering and what is it?
Pericardium; a sac surrounding the heart
What are the 3 layers of the pericardium and what are their functions?
1 layer = Fibrous pericardium (protects the heart and anchors it to surrounding structures)
2 layers = Serous Pericardium Membranes; Parietal Pericardium (lines interior of fibrous pericardium) and Visceral Pericardium (part of the heart wall - also known as the epicardium)
What are the 3 layers of the heart wall and what are they made up of?
- Epicardium = visceral pericardium
- Endocardium = thin sheet of endothelium that lines the heart chambers
- Myocardium = thick bundles of cardiac muscle tissue twisted into ring-like structures; this is the part that contracts
What is the function of the pericardial sac/ cavity?
Collects serous fluids released by membranes which keeps the heart moist so it can beat without friction
What is the pulmonary circuit?
Right ventricle –> Lungs –> Left atrium
Low pressure
What is the systemic circuit?
Left ventricle –> Body tissues –> Right atrium
High pressure
What is the difference between the right and left walls of the heart?
The wall of the left ventricle is thicker as it needs to pump blood around the whole body
What is cardiac output?
The volume of blood pumped out of the heart from each ventricle in 1 minute
How much of the blood volume does the heart receive?
5%
What is the purpose of the blood that is supplied to the heart?
To nourish and oxygenate the myocardium
Describe the location of the coronary arteries
Branch from the aorta and encircle the coronary sulcus (AV groove)
What are the names of the 4 branches of the coronary arteries?
- Anterior interventricular artery (LEFT)
- Circumflex artery (LEFT)
- Posterior interventricular artery (RIGHT)
- Marginal artery (RIGHT)
How does the blood leave the myocardium?
Its drained by the cardiac veins which empty into an enlarged vessel called the coronary sinus
What is another name for the SAN (Sinoatrial Node) and why?
The ‘pacemaker’ because it initiates the heartbeat
Describe the process of a heartbeat
- Impulses spread across the atria from the SAN and cause them to contract
- Impulses reach the AVN which delays them by 0.1 second to allow the atria to finish contracting
- Impulses spread to the Bundle of His which conducts them to the base of the ventricles
- Purkinje fibres spread the impulses up and out, causing the ventricles to contract from the bottom up
What is the definition of a cardiac cycle?
The chain of events that occurs in one heartbeat, including pressure changes and contractions
Describe the relationship between the sounds that the heart makes
lub = AV valves closing dub = SL valves closing