Gross anatomy of the heart and coronary circulation

Dr Emily Hunter's lecture

What are the chambers of the heart?

The right atrium, the right ventricle, the left atrium and the left ventricle.

What are the great vessels of the heart?

The superior/inferior vena cava, the pulmonary arteries, the pulmonary veins and the aorta.

Which costal cartilages does the right side of the heart run between?

The 3rd to the 6th (parasternal line)

Which costal cartilages does the left side of the heart run between?

From the 2nd to the 5th (midclavicular line)

Between which thoracic vertebrae does the posterior surface of the heart run between?

The 5th and the 8th.

What is the pericardium?

It is a series of continuous fibro-serous membranes that surround the heart.

What are the two layers of the pericardium?

The parietal and visceral pericardium.

What is another name for the visceral pericardium?

Another name for the visceral pericardium is the epicardium.

What is the pericardial cavity?

It is a fluid filled cavity that is found between the parietal and visceral pericardium. The serous fluid prevents friction as the heart beats.

What are the two pericardial sinuses of the heart?

The transverse and the oblique sinuses.

What are the rough locations of each of the pericardial sinuses?

The transverse pericardial sinus is the area that can be accessed by pushing the finger posterior to the aorta and the pulmonary trunk.

The oblique pericardial sinus is between the pulmonary veins

What are the difference surfaces of the heart?

The sternocostal surface, the left/right pulmonary surfaces the posterior surface (base) and the diaphragmatic surface.

What are the borders of the heart?

The superior border, the left border, the apex, the inferior border and the right border.

What is the function of the atria compared to the function of the ventricles?

The atria are simple receiving chambers that have the sole purpose of filling the ventricles.

The ventricles are responsible for pumping the blood to either the lungs or around the body.

What is the comparison between the walls of the atria versus the ventricles?

The atria have thin walls whereas the ventricles have thicker walls. The left ventricle has a thicker wall than the right ventricle.

Why does the left ventricle have thicker walls than the right ventricle?

Because the left ventricle is responsible for pumping blood around the whole body whereas the right ventricle is just responsible for pumping blood to the lungs.

Which border of the heart does the right atrium form?

The right border of the heart.

What drains into the right atrium?

The superior/inferior vena cava and the coronary sinus.

What makes up the anterior and posterior wall of the right atrium?

The posterior wall is referred to as sinus venarum - smooth posterior wall.

The anterior wall is referred to as muscalini pectinati - rough anterior wall.

What is responsible for separating the rough and the smooth walls of the right atrium?

The crista terminalis.

The crista terminalis is located interiorly of the right ventricle, what is the corresponding structure that is located on the exterior surface of the heart?

The sulcus terminalis is the corresponding structure to the crista terminalis on the external surface of the heart.

Through which valve does blood pass from the right atrium to the right ventricle?

The tricuspid valve.

What are the different sections of the primitive heart tube?

The truncus arteriosus, bulbous cordis, primitive ventricle, primitive atrium and the sinus venosus.

What adult structures arise from the truncus arteriosus?

The ascending aorta and the pulmonary trunk.

What adult structures arise from the bulbous cordis?

The smooth parts of the left and right ventricles - the infundibulum of the right ventricle and the outflow tract of the left ventricle.

What adult structures arise from the primitive ventricle?

The trabeculated portions of the left and right ventricles.

What adult structures arise from the primitive atrium?

The rough portions of the left and right atria (muscalini pectinati).

What adult structure arises from the sinus venosus?

The smooth portion of the right atrium, the coronary sinus and the oblique vein of the left atrium.

Where can the fossa ovalis be located?

The wall of the right atrium.

How is blood passed from the right ventricle into the pulmonary arteries?

Through the infundibulum (smooth aspect of the right ventricle) and the pulmonary valve.

What is the name of the rough structures found in the ventricles?

The trabeculae carnae.

What are the names of the chords that attach the cusps of the atrioventricular valves to the wall of the ventricles? What is the name of the muscles present too?

The chordae tendinae are the cords that attach to the cusps of the valves to the ventricle walls. The papillary muscles are the muscles that are present.

What separates the two ventricles?

The interventricular septum.

What are the different aspects of the conducting system?

The sinoatrial node that is located in the superior aspect of the right atrium, the atrioventricular node that is located in the inner wall of the right atrium, above the atrioventricular septum. The atrioventricular bundle/bundle of His. The left and right bundle branches that pierce through the interventricular septum. Finally, the purkinje fibres.

Which surface of the heart does the left atrium form?

The posterior surface/base of the heart.

What drains into the left atrium?

The 4 pulmonary veins.

Through which valve does blood pass from the left atrium to the left ventricle?

The mitral (bicuspid) valve.

Through which valve does blood pass from the left atrium to the left ventricle?

The aortic valve.

What are the key features of the left ventricle?

Trabeculae carnae, chordae tendinae and papillary muscles.

What are the functions of the fibrous skeleton of the heart?

It anchors the heart muscle, keeps the valves patent, provides attachment for the cusps and leaflets of the valves and acts as electrical insulation between the atria and ventricles.

Why is it important that the fibrous skeleton of the heart provides electrical insulation between the atria and the ventricles?

Because it is important that there is independent contraction of the atria and the ventricles.

What is meant by the term semi-lunar valves?

They are the valves that are found between the ventricles and the great vessels. The pulmonary (R) and aortic (L) valves are examples.

What is the difference between the atrioventricular and semi-lunar valves?

The semi-lunar valves do not have chordae tendinae or papillary muscles that attach the cusps of the valves to the walls of the ventricles.

Where can each of the valves of the heart be auscultated?

The aortic valve is auscultated at the second intercostal space on the right at the parasternal border.

The pulmonary valve is auscultated at the second intercostal space on the left at the parasternal border.

The tricuspid valve is auscultated at the 5th intercostal space at the parasternal border.

The mitral valve is auscultated at the 5th intercostal space at the midclavicular line.

When do coronary arteries get filled?

During diastole. The aortic valve closes and the blood that is left above the valve flows into the coronary arteries via the coronary sinuses.

Where does the right coronary artery originate from?

The right aortic sinus.

What does the right coronary ‘run’ down?

The atrioventricular groove.

What does the right coronary artery supply?

The right atrium, the right ventricle and the posterior 1/3rd of the interventricular septum.

Which coronary artery typically supplies the sinoatrial node?

The right coronary artery.

Which coronary artery typically supplies the atrioventricular node?

The right coronary artery.

Where does the marginal artery branch from the right coronary artery and where does it extend to?

The marginal coronary artery branches from the right coronary artery at the inferior border of the heart and extends to the apex of the heart.

Which artery gives off the posterior descending coronary artery in 85% of people?

The right coronary artery usually gives off the posterior descending coronary artery in most people.

Where does the left coronary artery originate from?

The left aortic sinus.

What is the difference between the left and right coronary artery?

The left coronary artery is larger than the right coronary artery. But the left coronary artery is shorter than the right coronary artery.

What does the left coronary artery bifurcate into?

Into the left anterior descending and the left circumflex.

What does the left coronary artery supply?

The left atrium. the left ventricle and the anterior 2/3rds of the interventricular septum.

Which cardiac vein accompanies the left anterior descending coronary artery?

The great cardiac vein accompanies the left anterior descending coronary artery.

Which cardiac vein accompanies the posterior descending coronary artery?

The middle cardiac vein accompanies the posterior descending coronary artery.

Which cardiac vein accompanies the marginal coronary artery?

The small cardiac vein accompanies the marginal coronary artery.

Where is the oblique cardiac vein?

It descends from the left atrium.

Which cardiac veins drain into the coronary sinus?

The great, middle, small and oblique cardiac vein drain into the coronary sinus which then drains into the right atrium.

What is the role of the anterior cardiac vein?

It collects blood from the right ventricle and drains it into the right atrium.