Heart

What are the functions of the cardiovascular system?

Transport substances to and from body cells, generate blood pressure, exchange nutrients and wastes at capillaries, and regulate blood flow.

Where is the heart located?

In the mediastinum, slightly left of the midline.

About what size is the heart?

About the size of a fist.

What is the epicardium?

The outer layer of the heart; the visceral layer of the serous pericardium.

What is the myocardium?

Heart muscle, responsible for contraction.

What is the endocardium?

Lines the heart chambers, covers valves.

What is the fibrous pericardium?

The tough outer sac that surrounds and protects the heart.

What is the function of the serous pericardium and pericardial fluid?

Reduces friction as the heart beats.

What are the atria?

The two upper receiving chambers of the heart.

What are the ventricles?

The two lower pumping chambers of the heart.

What is the tricuspid valve?

The AV valve between the right atrium and right ventricle.

What is the bicuspid (mitral) valve?

The AV valve between the left atrium and left ventricle.

What is the pulmonary semilunar valve?

The valve between the right ventricle and pulmonary trunk.

What is the aortic semilunar valve?

The valve between the left ventricle and the aorta.

What is the function of the chordae tendineae?

Hold the AV valves in place and prevent blood flow backwards.

What is the function of the papillary muscles?

Tighten the chordae tendineae during ventricular contraction.

What do the coronary arteries do?

Supply oxygenated blood to the heart muscle.

What is the function of the superior vena cava?

Returns deoxygenated blood from the body into right atrium.

What is the function of the aorta?

Carries oxygenated blood from the left ventricle to the body.

What is the function of the pulmonary arteries?

Carry deoxygenated blood from the right ventricle to the lungs.

What is the function of the pulmonary veins?

Carry oxygenated blood from the lungs to the left atrium.

What is the SA node?

The heart's natural pacemaker that initiates each heartbeat.

What is the AV node?

Delays the electrical impulse before it reaches the ventricles.

What is the Bundle branches?

Run toward the apex of the heart carrying the electrical message with them.

What are Purkinje fibers?

Allows the ventricles to contract in a coordinated manner.

How does the intrinsic conduction system differ from the autonomic nervous system?

The intrinsic system generates the heartbeat; the autonomic nervous system speeds up or slows down the heart rate.

What does the P wave represent on an ECG?

Atrial depolarization.

What does the QRS complex represent on an ECG?

Ventricular depolarization.

What does the T wave represent on an ECG?

Ventricular repolarization.

What is systole?

The contraction phase of the heart when pressure is highest.

What is diastole?

The relaxation phase of the heart when the chambers fill with blood and pressure is lowest.

What is the correct order of blood flow through the heart?

Right atrium → Tricuspid valve → Right ventricle → Pulmonary semilunar valve → Pulmonary trunk → Lungs → Pulmonary veins → Left atrium → Bicuspid valve → Left ventricle → Aortic semilunar valve → Aorta.

What is the pulmonary circuit?

Carries deoxygenated blood to the lungs and returns oxygenated blood to the heart.

What is the systemic circuit?

Carries oxygenated blood to the body and returns deoxygenated blood to the heart.

What is the coronary circuit?

Supplies oxygenated blood to the heart muscle itself.

During which phase is blood pressure highest?

Systole.

What causes the first heart sound?

Systole.

What causes the second heart sound?

Diastole.

What is cardiac output?

The volume of blood pumped by each ventricle per minute.

What two factors determine cardiac output?

Heart rate (HR) and stroke volume (SV).

What is the formula for cardiac output?

CO = HR × SV.