Heart Anatomy

Question 1

Describe the direction of blood flow through the heart and lungs

Answer 1

1) deoxygenated blood enters right atria via superior and inferior vena cava
2) blood enters right ventricle via tricuspid valve
3) blood is pumped into pulmonary trunk via pulmonary valve
4) pulmonary trunk splits into right and left pulmonary arteries, carrying blood to each lung
5) pulmonary veins return oxygenated blood into left atrium via superior and inferior pulmonary veins
6) blood enters left ventricle via mitral valve
7) blood enters ascending aorta via aortic valve

Question 2

What are the 4 valves of the heart?

Answer 2

Tricuspid: between right atrium and ventricle

Pulmonary: between right ventricle and pulmonary trunk

Mitral: between left atrium and left ventricle

Aortic: between left ventricle and ascending aorta

Question 3

What are the 4 surfaces of the heart?

Answer 3

Diaphragmatic: inferior surface, mostly left ventricle

Left pulmonary: mostly left ventricle

Right pulmonary: mostly right atrium

Sternocostal: mostly right ventricle

Question 4

What are the 4 borders of the heart?

Answer 4

Right: between SVC and IVC, right atrium

Left: left ventricle and auricle, oblique plane

Inferior: mostly right ventricle and some left ventricle

Superior: both atria and auricles, passage for SVC, ascending aorta and pulmonary trunk

Question 5

What are the 5 layers encasing the heart?

Answer 5

1) Pericardium -fibrous outer layer
2) Pericardium -serous inner layer (parietal component) - separated from visceral component by fluid filled space
3) Pericardium / Epicardium - serous inner layer (visceral component)
4) Myocardium -cardiac muscle, bulk of heart wall
5) Endocardium - epithelial lining of internal heart wall

Question 6

Where does the pericardium anchor?

Answer 6

To the central tendon of the diaphragm

Question 7

What are the auricles?

Answer 7

‘Ear’ shaped protrusions of the right and left atrium.

right: overlaps ascending aorta
left: overlaps root of pulmonary trunk

Question 8

What are the sinuses?

Answer 8

Pulmonary sinuses:

• left, right and anterior
• superior to each cusp of pulmonary valve

Aortic sinuses:

• left, right and posterior
• superior to each cusp of aortic valve
• receive left and right coronary artery (into left and right sinus)

Coronary sinus:

• main venous drainage of the heart muscle (not the chambers of the heart)
• runs from left to right along posterior coronary groove
• cardiac veins drain into coronary sinus
• coronary sinus drains directly into right atrium

Question 9

What is the venous and arterial supply of the heart itself (not the chambers)

Answer 9

Arterial supply:

• coronary arteries (left and right)
• first branches of the aorta at the aorta sinus (from left and right aortic sinus respectively)
• supply most of myocardium & epicardium with blood
• endocardium supplied by diffusion from chambers

Coronary sinus:

• cardiac veins drain into coronary sinus, which runs from left to right on the posterior surface of the heart along posterioro coronary groove
• coronary sinus drains directly into right atrium

Question 10

What are the chordae tendinae and papillary muscles?

Answer 10

Chordae tendinae are string like processes connected to adjacent cusps of the valves between atria and ventricles, and attached to the papillary muscles, and function to prevent the valves from being pulled in the wrong direction

Papillary muscles are conical projections of muscle into ventricular space (3 in right and w in left) that contract at the same time as the ventricles to pull the chordae tendinae taut and prevent the valve from being pushed into the atrium by ventricular pressure

Question 11

Which nerves innervate the heart?

Answer 11

Parasympathetic supply: CNX Vagus

Sympathetic supply: ventral rami of T1-5/6 via cardiopulmonary splanchnic nerves