Anatomy Quiz on the Heart

Where is the heart located in the thorax?

In the mediastinum: posterior to the sternum, anterior to the thoracic vertebrae, medial to both lungs, and superior to the diaphragm.

What is the mediastinum?

The region of the thoracic cavity between the lungs where the heart is located.

Which chamber of the heart rests on the diaphragm?

The right ventricle.

Why is the heart described as a dual pump?

The right and left sides act as two separate pumps.

How do the walls of the atria compare with the ventricles?

The atria are thin-walled, while the ventricles have thicker walls.

What does the interatrial groove separate?

The right and left atria.

What is another name for the coronary sulcus?

The atrioventricular groove.

Where is the coronary sulcus located?

Between the atria and ventricles.

What important arteries travel in the coronary sulcus?

The right and left coronary arteries.

What does the anterior interventricular sulcus mark?

The boundary between the ventricles on the anterior surface.

What does the posterior interventricular sulcus mark?

The boundary between the ventricles on the posterior surface.

What is the general blood-flow pathway through the right heart?

Right atrium → tricuspid valve → right ventricle → pulmonary semilunar valve → pulmonary trunk → pulmonary arteries.

What is the general blood-flow pathway through the left heart?

Pulmonary veins → left atrium → mitral valve → left ventricle → aortic valve → aorta.

What vessels return systemic blood to the right atrium?

Superior vena cava, inferior vena cava, and coronary sinus.

What is an auricle?

A muscular pouch that extends from each atrium.

What is the function of an auricle?

It expands atrial capacity so extra blood can be held during high demand without greatly increasing pressure.

What does the right auricle overlap?

The ascending aorta.

What does the left auricle overlap?

The pulmonary trunk.

What is the sinus venarum?

The smooth, thin-walled posterior portion of the right atrium.

Which vessels open into the sinus venarum?

The SVC, IVC, and coronary sinus.

Where are pectinate muscles located in the right atrium?

In the rough anterior wall.

What are pectinate muscles?

Parallel muscular ridges that resemble the teeth of a comb.

What separates the right and left atria?

The interatrial septum.

What is the foramen ovale?

A fetal opening in the interatrial septum.

What normally happens to the foramen ovale after birth?

It closes after birth and becomes permanently sealed.

What is the fossa ovalis?

The depression remaining at the site of the closed foramen ovale.

What is a patent foramen ovale?

Persistence of the fetal opening in the interatrial septum after birth.

What valve is between the right atrium and right ventricle?

The tricuspid, or right atrioventricular, valve.

How many cusps does the tricuspid valve have?

Three: anterior, posterior, and septal.

What are chordae tendineae?

Tendinous cords connecting AV valve cusps to papillary muscles.

What are papillary muscles?

Conical ventricular muscles attached to AV valve cusps by chordae tendineae.

What is the function of the papillary muscles and chordae tendineae?

They prevent AV valve leaflets from prolapsing into the atria during ventricular contraction.

Why are the tricuspid valve, chordae tendineae, and papillary muscles important?

Together they help prevent backflow of blood into the right atrium.

Which tricuspid cusps receive chordae from the anterior papillary muscle?

Anterior and posterior cusps.

Which tricuspid cusps receive chordae from the posterior papillary muscle?

Posterior and septal cusps.

Which tricuspid cusps receive chordae from the septal papillary muscle?

Anterior and septal cusps.

What are trabeculae carneae?

Irregular muscular ridges making up much of the ventricular wall.

What is the conus arteriosus?

The smooth superior portion of the right ventricle leading to the pulmonary semilunar valve.

How thick is the interventricular septum?

It is approximately as thick as the left ventricular wall.

Why is the left ventricle thicker than the right ventricle?

It must pump against the high resistance and pressure of systemic circulation.

How does systemic circulation compare with pulmonary circulation?

Systemic circulation is a high-pressure, high-resistance system.

How many cusps are in the pulmonary semilunar valve?

Three.

Do semilunar valves have chordae tendineae?

No. Unlike AV valves, they do not have chordae tendineae.

What opens the pulmonary semilunar valve?

Increasing pressure inside the right ventricle during contraction.

Where does blood go after passing through the pulmonary semilunar valve?

Into the pulmonary trunk and then the right and left pulmonary arteries.

Which vessels return blood to the left atrium?

The right and left pulmonary veins.

What type of blood do the pulmonary veins contain?

Oxygenated blood returning from the lungs.

What is the general appearance of the left atrial wall?

Most of the left atrium has smooth walls.

Where are pectinate muscles located in the left atrium?

Only in the left auricle.

What valve is between the left atrium and left ventricle?

The bicuspid, mitral, or left AV valve.

How many cusps does the mitral valve have?

Two: anterior and posterior.

Which papillary muscles are present in the left ventricle?

Anterior and posterior papillary muscles.

How do left ventricular papillary muscles compare with those on the right?

They are larger.

How much thicker is the left ventricular wall than the right?

Approximately 2–3 times thicker.

What is the aortic vestibule?

The smooth superior portion of the left ventricle leading to the aortic semilunar valve.

How many cusps does the aortic semilunar valve have?

Three.

Where does blood enter after passing through the aortic semilunar valve?

The ascending aorta.

Why does the myocardium require a separate coronary circulation?

The heart walls are too thick for all cells to receive enough oxygen and nutrients from blood in the chambers.

Where do the right and left coronary arteries originate?

From openings immediately outside the aortic semilunar valve.

What is the path of the right coronary artery?

It branches to the right of the aorta and travels along the coronary sulcus.

What are major branches of the RCA?

Atrial branches, anterior ventricular branches, right marginal branch, and posterior interventricular branch.

What is another name for the posterior interventricular artery?

The right posterior descending artery, or R-PDA.

What determines right versus left coronary dominance?

Whether the right or left coronary artery gives rise to the posterior interventricular/PDA artery.

How does the diameter of the LCA usually compare with the RCA?

The left coronary artery is usually larger in diameter.

What is another name for the anterior interventricular branch of the LCA?

The left anterior descending artery, or LAD.

Which artery does the LAD anastomose with?

The right posterior descending artery.

What is the diagonal artery?

A branch of the LAD that is important in collateral circulation to ventricular areas.

What are major branches associated with the circumflex artery?

Left atrial branches, left marginal branch, and posterior ventricular branch.

What is collateral coronary circulation?

Alternative blood supply to the same region produced through vessel connections or anastomoses.

What happens during a heart attack according to the lecture?

A coronary vessel becomes completely blocked, causing the cardiac tissue supplied by it to die.

Why does the site of a coronary blockage affect the outcome of a heart attack?

Different coronary vessels supply different regions of the heart.

How can existing collateral circulation affect a coronary blockage?

Dual blood supply through anastomoses may provide another route of blood to the affected area.

Where does the majority of cardiac venous blood drain?

Into the coronary sinus, which drains into the right atrium.

Which cardiac vein travels with the LAD?

The great cardiac vein.

Which cardiac vein travels with the right posterior descending artery?

The middle cardiac vein.

Which cardiac vein travels with the right marginal artery?

The small cardiac vein.

Which vein accompanies the left posterior ventricular artery?

The posterior vein of the left ventricle.

Where do the anterior cardiac veins drain?

Directly into the right atrium.

What are the three layers of the heart wall?

Endocardium, myocardium, and epicardium.

What is the endocardium?

The thin inner layer of the heart that contacts blood in the atria and ventricles.

What is the myocardium?

The contractile cardiac muscle layer.

What is the epicardium also known as?

The visceral pericardium.

What lies between the visceral and parietal pericardium?

The pericardial cavity.

What is the most superficial layer surrounding the heart?

The fibrous pericardium.

Are the visceral and parietal pericardium separate membranes?

They are continuous; the visceral layer folds near the great vessels to become the parietal layer.

What is mesothelium in the pericardium?

A single epithelial cell layer lining the pericardial cavity.

What does the serous pericardium secrete?

Pericardial fluid.

What is the function of pericardial fluid?

It reduces friction as the beating heart moves inside the pericardial sac.

What type of tissue forms the fibrous pericardium?

Dense connective tissue.

What does the fibrous pericardium attach to?

It is fused to the parietal pericardium.

What are the functions of the pericardial sac?

It maintains heart position, protects against infection from nearby lungs, and contains lubricating pericardial fluid.

What is pericarditis?

Inflammation of the pericardium.

What are possible causes of pericarditis listed in the slides?

Viral infection, bacterial infection, lupus, cancer, and injury

What characteristic sound may occur with pericarditis?

A friction rub.

How can severe pericarditis lead to cardiac tamponade?

Inflammation can cause additional fluid to accumulate around the heart and increase pressure on it.

Why can fluid accumulation around the heart become dangerous?

The fibrous pericardium is not stretchy, so accumulating fluid raises pressure on the heart.

What is pericardiocentesis?

A procedure used to remove fluid from around the heart, performed with ultrasound imaging.

Where does the internal thoracic artery originate?

From the subclavian artery.

What is another name for the internal thoracic artery?

The internal mammary artery.

What arteries arise from the internal thoracic artery to supply intercostal spaces anteriorly?

Anterior intercostal arteries.