heart
Which part of the nervous system stimulates the SA node to accelerate the heart rate?
Sympathetic
What is the adult remnant of the foramen ovale?
Fossa ovalis
What is the function of the foramen ovale in foetal circulation?
It shunts blood from the right atrium to the left atrium, bypassing the lungs.
Which vein drains most of the venous blood from the myocardium and empties into the right atrium via the coronary sinus?
Great cardiac vein
Which coronary artery typically supplies the anterior two-thirds of the interventricular septum?
Left anterior descending artery (LAD)
Where is the coronary sinus located and where does it terminate?
The coronary sinus runs in the posterior coronary groove and empties into the right atrium
Which structure electrically isolates the atria from the ventricles ?
Fibrous skeleton of the heart
Which part of the cardiac conducting system forms the bridge through which the electrical signal is conducted between the atria and ventricles?
AV bundle
What is the physiological role of the ductus arteriosus in foetal circulation?
It shunts blood from the pulmonary trunk to the aorta, bypassing the non-functioning lungs.
What is the name of the opening in the interatrial septum that allows blood to flow directly from the right atrium to the left atrium in the foetus?
Foramen ovale
Which cardiac veins drain directly into the right atrium?
Anterior cardiac veins
Name the components of the cardiac conducting system
Sinoatrial node (SA node)
Atrioventricular node (AV node)
Atrioventricular bundle (AV bundle/bundle of His)
Right bundle branch
Left bundle branch
Purkinje fibres
Which part of the cardiac conducting system passes through the moderator band?
Fibres of the right AV bundle
What is the adult remnant of the ductus arteriosus?
ligamentum arteriosum
What is the name of the foetal vessel that shunts blood from the pulmonary trunk to the aorta?
Ductus arteriosus
During what stage of the coronary cycle to the coronary arteries fill?
Diastole
The great cardiac vein is the main tributary Of the coronary sinus. It arises at the apex and runs in the anterior interventricular groove. Which artery does it accompany?
The great cardiac vein accompanies the anterior interventricular artery
The middle cardiac and small cardiac veins also drain into the coronary sinus. Which arteries do they accompany?
The middle cardiac vein accompanies the posterior interventricular artery, the small cardiac vein accompanies the RCA
Where do the fibres running in the moderator band lead to?
Anterior papillary muscles
What is the function of the moderator band?
Equalises conduction time through right and left ventricles to provide a coordinated contraction
Why do coronary arteries fill when they do
During systole, when the valve is open, the ostia of the coronary vessels are covered by the cusps of the valve so blood cannot enter. During diastole, blood is forced back toward the heart and fills the cusps. The ostia are exposed and blood can flow into the coronary vessels. This ensures that blood flows through the heart when the muscle is relaxed.
Where does the right coronary artery arise and pass
arises from the right aortic sinus of the ascending aorta and passes in the anterior coronary groove.
Typically the right coronary artery (RCA) is dominant (67% of population). In this case, which regions of the heart are supplied by the RCA?
Typically the right coronary artery supplies the
• Right atrium
• Most of right ventricle
• Diaphragmatic surface of left ventricle
• Posterior third of interventricular septum
• SA node (60% of population)
• AV node
What are Arterio-arterial anastomosis?
connections between blood vessels that provide an alternative/back-up route of circulation if one vessel is blocked.
stats Two examples in the coronary circulation and the vessels involved in each case.
right coronary artery with circumflex artery
anterior interventricular artery (LAD) with posterior interventricular artery