heart anatomy structures, chambers, and valves

How many chambers does the heart have?

Four.

What are the upper chambers called?

Atria.

What are the lower chambers called?

Ventricles.

Main function of the atria

Receive blood returning to the heart.

Main function of the ventricles

Pump blood away from the heart.

What does the right atrium receive?

Deoxygenated blood from the body and heart tissue.

Which vessels empty into the right atrium?

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

What does the superior vena cava drain?

Head, neck, upper limbs, and superior thorax.

What does the inferior vena cava drain?

Abdomen, pelvis, and lower limbs.

What does the coronary sinus drain?

Blood from the myocardium/heart tissue.

What does the left atrium receive?

Oxygenated blood from the lungs.

Which vessels empty into the left atrium?

Four pulmonary veins.

What does the right ventricle pump blood into?

Pulmonary trunk.

Where does the pulmonary trunk send blood?

To the pulmonary arteries and then the lungs.

What does the left ventricle pump blood into?

Aorta.

Where does the aorta send blood?

To the systemic circuit/body.

What are auricles?

Ear-like extensions of the atria that increase atrial volume.

Where are pectinate muscles located?

In the atria, especially the right atrium and auricles.

What are pectinate muscles?

Ridges of muscle in the atrial walls.

Function of pectinate muscles

Help atria contract and increase strength without greatly increasing mass.

What is the fossa ovalis?

A depression in the interatrial septum.

What is the fossa ovalis a remnant of?

The fetal foramen ovale.

What did the foramen ovale do in fetal circulation?

Allowed blood to pass from the right atrium to the left atrium, bypassing fetal lungs.

What is the interatrial septum?

The wall between the right and left atria.

What is the interventricular septum?

The wall between the right and left ventricles.

What are trabeculae carneae?

Irregular muscular ridges inside the ventricles.

Function of trabeculae carneae

Help prevent suction/sticking of ventricular walls and aid contraction.

What are papillary muscles?

Muscles in ventricles attached to chordae tendineae.

Function of papillary muscles

Contract to hold chordae tendineae tight and prevent AV valve prolapse.

What are chordae tendineae?

Tendon-like cords connecting AV valve cusps to papillary muscles.

Function of chordae tendineae

Prevent AV valves from flipping backward into the atria.

What are AV valves?

Valves between atria and ventricles.

What are the two AV valves?

Tricuspid valve and mitral/bicuspid valve.

Where is the tricuspid valve located?

Between the right atrium and right ventricle.

Where is the mitral/bicuspid valve located?

Between the left atrium and left ventricle.

Why is it called the tricuspid valve?

It has three cusps.

Why is it called the bicuspid valve?

It has two cusps.

What are semilunar valves?

Valves between ventricles and great arteries.

What are the two semilunar valves?

Pulmonary semilunar valve and aortic semilunar valve.

Where is the pulmonary semilunar valve?

Between the right ventricle and pulmonary trunk.

Where is the aortic semilunar valve?

Between the left ventricle and aorta.

Main function of heart valves

Prevent backflow of blood.

When do AV valves open?

When atrial pressure is greater than ventricular pressure.

When do AV valves close?

When ventricular pressure becomes greater than atrial pressure.

When do semilunar valves open?

When ventricular pressure becomes greater than arterial pressure.

When do semilunar valves close?

When arterial pressure becomes greater than ventricular pressure.