Coronary Circulation and Conduction System Flashcards
What supplies the heart?
Coronary arteries and their branches:
- right coronary artery
- left coronary artery
Where do the coronary arteries come from?
The aortic sinuses
When do the coronary arteries fill with blood?
During diastole
What are the branches of the right coronary artery?
- SA nodal branch
- AV nodal branch
- posterior interventricular branch
- right acute marginal branch
What are the physiological differences in the left coronary artery to the right?
It is shorter but thicker than the right coronary artery
What are the branches of the left coronary artery?
- circumflex artery
- anterior interventricular artery
What does the SA nodal branch supply?
- supplies the SA node
- atrial branches supply the right atrium
What does the anterior interventricular branch supply?
Sternocostal surface
What is named the ‘artery of sudden death’?
Anterior interventricular artery
What are the branches of the circumflex branch of the left coronary artery?
left obtuse marginal branch
Where do the branches of the left and right coronary artery anastomose?
Coronary sulcus on the apex of the heart
What does the right coronary artery and its branches supply?
- walls of right atrium and ventricle
- SA and AV nodes
- posterior part of IV septum
- small areas of the walls of left atrium and ventricle
What does the left coronary artery and its branches supply?
- walls of LA and LV
- most of IV septum including part of AV bundle
What determines coronary dominance?
- the artery that gives off the posterior interventricular artery
- majority of people are right coronary artery dominant
What is the most common cause of MI?
Occlusion of the left anterior descending artery
What are the possible solutions for coronary artery occlusion/narrowing?
- coronary artery bypass grafting
- coronary angioplasty (alternative to CABG)
How does coronary artery bypass grating work?
bypass the occluded portion of the vessel with the:
- internal thoracic artery/internal mammary artery
- great saphenous vein (if ITA isn’t possible)
How does coronary angioplasty work?
- catheter is passed usually into femoral artery
- thin wire is guided through vessel to deliver stent/balloon to affected area
- balloon is inflated to expand stent which implants it and restores circulation
What is another name for coronary angioplasty?
percutaneous transluminal coronary angioplasty
Where do cardiac veins drain to?
into right atrium through coronary sinus
What are the cardiac veins and where do they drain to?
- great cardiac vein which joins coronary sinus
- small cardiac vein which accompanies right marginal branch
- middle cardiac vein drains to coronary sinus
- anterior cardiac veins which drain independently into the right atrium
Where is the coronary sinus found?
between left atrium and ventricle
Where does the blood that isn’t drained by the coronary sinus drain to?
smallest cardiac veins and anterior cardiac veins
Explain how the cardiac conduction system operates
- cardiac muscle fibres form the atrial and ventricular networks separated by fibrous skeleton
- specialised modified cardiac muscle cells beneath the endocardium can generate impulses without external stimuli
- cardiac muscle cells distribute electrical impulses through myocardium
- ensures synchronous contraction in proper sequence
- ANS shortens/prolongs cardiac cycle
