Coronary circulation Flashcards
What do coronary arteries do?
Supply myocardium with oxygen
What do cardiac veins do?
Drain away deoxygenated blood
Where does circumflex artery come from?
Left artery
Where does posterior descending artery come from?
Right coronary artery
What is regurgitation?
Valve is incompetent - opens in abnormal way
Where does left coronary artery come from?
Aorta - left cusp of aortic valve
Where does right coronary artery come from?
Right cusp of aortic valve
Coronary arteries
- Right coronary artery (RCA)
- RCA ostium - 3.2mm
- Left coronary artery (LCA)
- LCA ostium - 4mm
- Anterior interventricular artery (LAD)
- Circumflex artery
- Posterior interventricular artery (posterior descending)
- Right marginal artery
- Left marginal artery
Left coronary artery
- Usually larger
- Branches into LAD (comes off very quickly 2cm) (anterior interventricular artery)
- Left circumflex - left marginal artery is a branch of this
Right coronary artery
- In -85% of people, RCA gives off posterior descending artery, right dominant
- Right marginal artery
- Supplies SA nodal artery in 60% of people
- Supplies atrioventricular nodal branch in 80-90% of people
- (otherwise may be supplied by left circumflex, left dominant)
Venous drainage of heart
Small, middle and great cardiac veins and coronary sinus
What is coronary sinus?
Collection of veins draining together, drains blood from myocardium
Conduction in heart
- SAN - heart’s internal pacemaker RA wall initiates cardiac cycle setting rhythm. Electrical impulse spreads to:
- Atrioventricular node: connected top bundle of His
- Electrical signals arise in SAN in RA, which stimulates the atria to contract. The signals travel to the AVN (interatrial septum). After a delay, signal diverges and is conducted through L and R bundle of His to respective Purkinje fibres
What does accelerator nerve do in heart?
Releases neurotransmitter at SAN to increase HR
What does vagus nerve do in heart?
Releases neurotransmitter at SAN to decrease HR
