Coronary Circulation and Conduction System of the heart Flashcards
Where does the right coronary artery take origin/travel through and what are its branches?
Takes origin from the right side of the ascending aorta, runs in the right side of the AV groove and runs around the right side of the heart.
- Right coronary artery runs around the right side of the heart and continues in the AV groove on the posterior surface.
- Terminates as a posteriori IV branch which runs down along the posterior IV groove towards the apex of the heart.
- Posterior IV branch, right marginal branch and also some branches which supply the RA and the SA nodal branch.
àSA nodal branch which comes of the right coronary artery most often hooks into the auricle on the anterior surface of the heart towards the SVC.
àAlso gives off at the crux the AV nodal branch and these two branches supply some of the pacemaker cells of the heart- crucial for conduction system.
Where does the left coronary artery take origin/travel through and what are its branches?
Left coronary artery runs behind the pulmonary trunk and becomes visible in the left atrioventricular groove.
As it gets passed the auricle, it immediately branches into two named branches: branches into the circumflex branch going to the AV node and the anterior interventricular branch (AKA left anterior descending artery) which runs in the anterior interventricular groove.
Circumflex branch gives off another branch called the left marginal branch.
Percentages that the left and right coronary artery give off the SA and AV node branches.
Right: SA node (55%) AV node (90%) Left: SA node (45%) AV node (10%)
What does the right coronary artery supply?
Right atrium
Most of the right ventricle
What does the left coronary artery supply?
Left atrium
Most of the left ventricle
Where are the two anastomoses on the heart?
- Just proximal to the apex of the heart
2. Between the circumflex branch of the left coronary artery and the right coronary artery itself.
What occurs in Coronary heart disease?
Coronary heart disease can be thought of as blockages of these coronary arteries.
As a result, this will mean oxygen wont be be able to reach cardiac muscle and will cause tissue death.
When you get tissue death, it releases a range of signals that causes the action of sensory afferent neurons and thus causing pain.
What is an Angiography?
Angiography - involves passing a catheter through the femoral artery all the way up to the illiacs, abdominal aorta, which then bends nicely around the arch of the aorta.
Then they place the opening of the catheter just inside the coronary arteries.
After this they inject, radioactive opaque die which fills the arteries, so they can image as it is filling.
What happens in angioplasty?
If you had a narrowing, they would place a little balloon around the catheter, which would expand the balloon, and as it does, it pushes the fat/blockage against the walls until its clear again.
What happens in a Coronary bypass surgery?
If the angioplasty doesn’t work, they take a blood vessel from elsewhere, such as the most commonly used ‘saphenous vein’ and add it to the descending arch, distal to the blockage.Arteries that can be taken from structures that get blood supply from other arteries also.
What happens in a Triple bypass surgery?
• Alternatively, the radial artery can also be used as an replacement artery. Internal mammory ‘thoracic’ artery which is a branch of the subclavian, it can be dissected off the posterior aspect of the thoracic wall and run it all the way down and stitch to an artery distal to the blockage.
Describe the venous drainage of the heart.
• Between 2 ventricles posteriorly, adjacent to the posterior interventricular artery draining directly into the coronary sinus: MIDDLE CARDIAC VEIN
• From the anterior interventricular groove, travelling with the left circumflex artery, and enters coronary sinus from the right: GREAT CARDIAC VEIN
• Travelling with left marginal branch artery and drains left side of the heart: LEFT MARGINAL VEINS
• Right side of the heart drained mostly by: SMALL CARDIAC VEIN
• On the left ventricle posteriorly random vein: LEFT POSTERIOR VENTRICULAR VEIN
• Draining the left atrium: OBLIQUE VEIN
Coronary sinus, collects all the venous drainage from the heart and has a direct opening into the right atrium.
What is the function of the Purkinje fibres?
Branches that continue out and making all the way to the ventricular cardiac muscle fibres, and causing them to contract simultaneously.
What is the function of the Moderator band?
Provides impulse very quickly to the anterior papillary muscle by creating a short pathway for some of the purkinje fibres. It allows the anterior papillary muscle to contract at the same time with the other papillary muscles and prevents the tricuspid valve from everting.
What happens if you damage the SA node, and is this bad? What happens if you damage the AV node, and is this bad?
- If you damage SA node, by lack of blood supply, the AV node, can generate its own pace. Therefore damage to the SA node is not critical, because the AV node can create ventricular contractions on its own.
- However, without, atrial contraction, its not too bad, but without a functioning AV node, and a functioning ventricular system = END OF THE WORLD = DEAD.
