Coronary arteries Flashcards
where does the endocardium get its nutrients and oxygen from?
the blood in the chambers
Where do the coronary arteries emerge from?
the aortic sinuses
When do the coronary arteries fill?
During diastole
Describe the right coronary arteries and its branches
ANTERIOR
• gives off the SA nodal branch, the right atrial branch, right marginal branch
POSTERIOR:
• (R marginal), posterior inter ventricular (in 80% of peeps)
Describe the left coronary arteries and its branches
- Left coronary artery branches into the circumflex artery and the left anterior descending artery
- Circumflex branches off the left obtuse marginal branch
What surface of the heart is supplied by the right coronary artery and its branches?
The inferior surface
What surface of the heart is supplied by the left coronary artery and its branches?
The sternocostal/anterior surface
Where do the left and right coronary arteries anastomose?
• In the coronary sulcus at the apex
What does the right coronary artery and its branches supply?
- RA
- RV
- Sino atrial node
- Atrioventricular node
- Small areas of the LV, LA,
- posterior part of the interventricular septum (membranous part)
What does the left coronary artery and its branches supply?
- Left Atrium
- Left ventricle
- Most of the IV septum
Obstruction of the LAD
- Anterior infarct
* Loss of function of the left ventricle leading to fibrillation of the left ventricle leading to death
Obstruction of the circumflex artery
• Lateral infarct
Obstruction of the right coronary artery
• Inferior infarct
Mild narrowing of the right coronary artery
- Arrythmias
* Supply to the nodal branches is compromised
Mild narrowing of the coronary arteries in general
• May damage the conducting system causing bradycardia
What are the ways to treat atherosclerosis of the coronary arteries?
• Coronary artery bypass graft
- Suture in a vessel over the blockage
- internal thoracic artery
- great saphenous vein — VALVES!!!
• Coronary angioplasty
- with/without a stent
- anticoagulation medicine
- percutaneous transluminal coronary angioplasty
In a coronary angiogram, why should the patient turn sideways?
• Because of the sternal shadow
If viewing the left coronary artery and its branches in the coronary angiogram, what position are you viewing
Right anterior oblique view
What determines coronary dominance?
Which artery gives off the posterior inter ventricular artery
What are the cardiac veins?
- Great - with the LAD
- Small - accompanied by the right marginal artery
- Middle
- Anterior
Which of the cardiac veins drain into the coronary sinus?
- Great cardiac
* Middle cardiac
What is the coronary sinus surrounded by?
Muscle from the right atrium
Describe the cardiac conduction systems
- 2 networks of muscle fibres separated by the fibrous skeleton: Atrial and ventricular
- Specialsied, modified cardiac muscles directly underneath the endocardium, they distribute the impulse throughout the myocardium and generate electrical impulses without the external stimuli
What are the components of the cardiac conduction system?
- SA node
- AV node
- Bundle of HIS and the left and right bundle branches
- Purkinjie fibres
Where is the Sino-atrial node?
Anterior to the opening of the superior vena cava, upper end of crista terminalis
Where is the AV node?
• Postero-inferior part of the IA septum, close to the opening of the coronary sinus
Where is the right bundle branch?
In the septomarginal trabecula
Describe the nerves to the heart
• Cardioacceleratory and cardio inhibitory centres in the medullary reticular formation
• Superficial and deep cardiac plexuses
- inferior to the aortic arch, adjacent to the bifurcation of the pulmonary trunk and trachea
- supplies the conduction system: myocardium, coronary blood vessels
• Presynaptic sympathetic fibres T1-5 (6)
- increase heart rate and contraction
- dilate the coronary arteries
• Parasympathetic fibres reach in the vagus
- decrease the heart beat and contraction
- constrict coronary arteries
• General visceral afferents
What occurring to the organs causes pain?
• Stretching
• Ischaemia
• contraction
Visceral nerves that travel with the sympathetics are responsible
