Heart anatomy

Where does the heart lie?

Where does the heart lie?

In the middle mediastinum.

What surrounds the heart?

A fibroserous sac called Pericardium.

How is the pericardium differentiated?

Into an outer fibrous layer (fibrous pericardium) and an inner serous sac (serous pericardium) consisting of parietal and visceral layers.

What are the surfaces of the heart?

Apex, Sterno-costal (anterior surface), Base (posterior surface), Diaphragmatic (inferior surface).

How is the shape of the heart described?

Somewhat pyramidal.

How many chambers does the heart consist of?

4 chambers - 2 atria (right and left) & 2 ventricles (right and left).

How is the apex of the heart directed?

Downwards, forwards, and to the left.

What forms the apex of the heart?

Left ventricle.

At what level does the apex of the heart lie?

Left 5th intercostal space, 3.5 inches from the midline.

Why is the base of the heart called the base?

Because the heart is pyramid-shaped, and the base lies opposite the apex.

On what surface does the heart rest?

The heart rests on its diaphragmatic (inferior) surface, not on its base.

What forms the Sterno-costal surface (anterior surface) of the heart?

Mainly formed by the right atrium and the right ventricle.

How is the surface divided by the coronary groove?

Divided into an atrial part, formed mainly by the right atrium, and a ventricular part. The right 2/3 is formed by the right ventricle, while the left 1/3 is formed by the left ventricle.

What separates the right and left ventricles on the sterno-costal surface?

Anterior interventricular groove, which lodges the Anterior interventricular artery (branch of the left coronary) and the Great cardiac vein.

What artery is lodged in the Anterior interventricular groove?

Anterior interventricular artery (branch of the left coronary).

What vein is lodged in the Anterior interventricular groove?

Great cardiac vein.

What does the coronary groove lodge?

Right coronary artery.

What is another term for groove?

Sulcus.

What forms the diaphragmatic surface of the heart?

Formed by the two ventricles, mainly the left ventricle (left 1/3).

How is the diaphragmatic surface described?

Slightly concave as it rests on the diaphragm.

In what direction is the diaphragmatic surface directed?

Inferiorly and backward.

What separates the diaphragmatic surface from the base of the heart?

Posterior part of the coronary sulcus.

What groove separates the two ventricles on the diaphragmatic surface?

Posterior interventricular groove.

What structures are lodged in the posterior interventricular groove?

Posterior interventricular artery, Middle cardiac vein.

What artery is lodged in the posterior interventricular groove?

Posterior interventricular artery.

What vein is lodged in the posterior interventricular groove?

Middle cardiac vein.

What forms the base of the heart?

Formed by the two atria, mainly the left atrium, into which open 4 pulmonary veins.

In what direction is the base of the heart directed?

Backwards.

What is the location of the base of the heart?

Opposite middle thoracic vertebrae (5-7).

What structures separate the base of the heart from the vertebral column?

Descending aorta, esophagus, and oblique sinus of the pericardium.

What bounds the base of the heart inferiorly?

Posterior part of the coronary sulcus, which lodges the coronary sinus.

What conceals the upper border of the heart?

Ascending aorta and pulmonary trunk.

What forms the left border of the heart?

Mainly formed by the left ventricle + auricle of the left atrium.

What forms the right border of the heart?

Formed by the right atrium.

What forms the lower border of the heart?

Mainly formed by the right ventricle + apical part of the left ventricle.

How is the heart divided into chambers?

By vertical septa into four chambers: Left and right atria, and left and right ventricles.

What are the four chambers of the heart?

Left atrium, right atrium, left ventricle, and right ventricle.

How is the right atrium positioned relative to the left atrium?

Anterior to the left atrium.

How is the right ventricle positioned relative to the left ventricle?

Anterior to the left ventricle.

What are the components of the right atrium?

Main cavity and a small outpouching called the auricle.

What does the auricle of the right atrium resemble?

An upward protrusion resembling an ear.

Where is the vertical groove located on the outside of the right atrium?

At the junction between the right atrium and the right auricle.

What is the name of the vertical groove at the junction of the right atrium and the right auricle?

Sulcus terminalis.

What does the sulcus terminalis form on the inside of the right atrium?

A ridge called the Crista terminalis.

What divides the right atrium?

Crista terminalis.

How is the anterior part of the right atrium characterized?

Rough and trabeculated by bundles of muscle fibers, known as musculi pectinati.

Describe the posterior part of the right atrium.

Smooth, and it is referred to as the sinus venarum.

What is found in the interatrial septum of the right atrium?

An oval depression called fossa ovalis.

What is the margin of the fossa ovalis called?

Anulus ovalis.

Through which valve does blood leave the right atrium and enter the right ventricle?

Tricuspid valve.

What are the openings in the right atrium?

1. Superior Vena Cava (SVC) - has no valve. 2. Inferior Vena Cava (IVC) - guarded by a valve. 3. Coronary sinus - has a well-defined valve. 4. Right atrioventricular orifice - lies anterior to the opening of the coronary sinus, surrounded by a fibrous ring that gives attachment to the tricuspid valve. 5. Small orifices of small veins.

Which opening in the right atrium has no valve?

Superior Vena Cava (SVC).

Which opening in the right atrium is guarded by a valve?

Inferior Vena Cava (IVC).

Which opening in the right atrium has a well-defined valve?

Coronary sinus.

Where is the right atrioventricular orifice located?

Anterior to the opening of the coronary sinus, surrounded by a fibrous ring that gives attachment to the tricuspid valve.

How does the right ventricle communicate with the right atrium?

Through the atrioventricular orifice.

How does the right ventricle communicate with the pulmonary trunk?

Through the pulmonary orifice.

How does the thickness of the right ventricle wall compare to that of the left ventricle?

Thinner than the wall of the left ventricle.

What structures are present in the wall of the right ventricle?

Projections called trabeculae carneae.

Through what orifice does the right ventricle communicate with the right atrium?

Right atrioventricular orifice.

Through what orifice does the right ventricle communicate with the pulmonary trunk?

Pulmonary orifice.

What structures arise from the walls of the right ventricle and are called?

Large projections called papillary muscles.

Name the three papillary muscles in the right ventricle.

1. Anterior papillary muscle, 2. Posterior papillary muscle, 3. Septal papillary muscle.

What connects each papillary muscle to the cusps of the tricuspid valve?

Chordae tendineae.

Through which orifice does blood leave the right ventricle to the pulmonary trunk?

Pulmonary orifice.

How is the wall of the infundibulum characterized?

Smooth and contains no trabeculae.

What connects the interventricular septum to the anterior papillary muscle?

A muscular band called moderator band.

What is the width of the right atrioventricular (tricuspid) orifice?

About one inch wide, admitting tips of 3 fingers.

What guards the right atrioventricular orifice?

A fibrous ring that gives attachment to the cusps of the tricuspid valve.

How many cusps does the tricuspid valve have?

3 cusps (anterior, posterior, septal or medial).

How are the atrial surfaces of the tricuspid valve cusps characterized?

Smooth.

What do the ventricular surfaces of the tricuspid valve cusps give attachment to?

Chordae tendineae.

What surrounds the pulmonary orifice?

A fibrous ring that gives attachment to the pulmonary valve.

How many semilunar cusps does the pulmonary valve have?

3 cusps (2 anterior and 1 posterior).

How are the cusps of the pulmonary valve shaped?

Concave superiorly and convex inferiorly.

Through what orifice does the left atrium communicate with the left ventricle?

Atrioventricular orifice.

What part of the heart does the left atrium form?

Greater part of the base of the heart.

How is the wall of the left atrium characterized?

Smooth, except for small musculi pectinati in the left auricle.

How many pulmonary veins does the left atrium receive?

4 pulmonary veins.

Do the pulmonary veins have valves?

No, they have no valves.

Through which orifice does the left atrium send blood to the left ventricle?

Left atrioventricular orifice.

What guards the left atrioventricular orifice?

Mitral valve (bicuspid valve).

How does the thickness of the left ventricle wall compare to that of the right ventricle?

Thicker than that of the right ventricle.

From where does the left ventricle receive blood?

From the left atrium through the left atrioventricular orifice, which is guarded by the mitral (bicuspid) valve.

What is found in the wall of the left ventricle?

Trabeculae carneae.

How many large papillary muscles are found in the left ventricle?

2 (anterior and posterior).

To what are the papillary muscles attached by chordae tendinae?

Cusps of the mitral valve.

Through which orifice does blood leave the left ventricle?

Aortic orifice.

What is the part of the left ventricle leading to the ascending aorta called?

Aortic vestibule.

How is the wall of the aortic vestibule characterized?

Fibrous and smooth.

How does the size of the left atrioventricular (mitral) orifice compare to the right?

Smaller than the right, admitting only the tips of 2 fingers.

What guards the left atrioventricular orifice?

Mitral valve.

What surrounds the left atrioventricular orifice and gives attachment to the cusps of the mitral valve?

A fibrous ring.

How many cusps does the mitral valve have?

2 cusps - anterior cusp and posterior cusp.

Where does the anterior cusp of the mitral valve lie?

Anteriorly and to the right.

Where does the posterior cusp of the mitral valve lie?

Posteriorly and to the left.

How are the atrial surfaces of the mitral valve cusps characterized?

Smooth.

To what are the ventricular surfaces of the mitral valve cusps attached?

Chordae tendineae.

What surrounds the aortic orifice and gives attachment to the cusps of the aortic valve?

A fibrous ring.

How many cusps does the aortic valve have?

3 semilunar cusps.