Anatomy and Physiology of the Heart - ECGs Made Easy

Vocabulary practice cards reviewing key cardiovascular terms, heart structures, valves, cardiac cycle phases, autonomic controls, and hemodynamic measures from Chapter 1.

Base (heart)

The broad upper part of the heart.

Apex (heart)

The pointed inferior end of the heart, directed downward and to the left.

Epicardium

The outer surface of the heart, which also serves as the visceral serous pericardium.

Myocardium

The middle muscular layer of the heart wall that contracts and ejects blood.

Endocardium

The smooth inner lining of the heart chambers and valves.

Interatrial septum

The internal wall that separates the right atrium from the left atrium.

Interventricular septum

The internal wall that separates the right ventricle from the left ventricle.

Right atrium

Heart chamber that receives blood from the superior and inferior vena cava and coronary sinus, and sends it through the tricuspid valve.

Right ventricle

Heart chamber that receives blood from the right atrium and ejects it through the pulmonary valve into the pulmonary trunk and arteries.

Left atrium

Heart chamber that receives oxygenated blood from the pulmonary veins and sends it through the mitral valve.

Left ventricle

Heart chamber that receives blood from the left atrium and ejects it through the aortic valve into the aorta.

Tricuspid valve

An atrioventricular (AV) valve located between the right atrium and right ventricle.

Mitral (bicuspid) valve

An atrioventricular (AV) valve located between the left atrium and left ventricle.

Pulmonary valve

A semilunar valve located between the right ventricle and the pulmonary trunk.

Aortic valve

A semilunar valve located between the left ventricle and the aorta.

Chordae tendineae

Structures that attach AV valve leaflets to papillary muscles and prevent backward billowing during ventricular contraction.

S1

The first heart sound ('lub'), caused by AV valve closure at the start of ventricular systole.

S2

The second heart sound ('dub'), caused by semilunar valve closure at the start of ventricular diastole.

Point of maximal impulse

The site on the chest wall near the apex where cardiac impulse sounds transmit best.

Acute coronary syndrome

A condition involving a sudden reduction of coronary blood flow.

Angina

Ischemic chest discomfort resulting from inadequate oxygen supply to the myocardium.

Atrial systole

Cardiac cycle phase where atria contract and complete ventricular filling while AV valves are open.

Early ventricular systole

Cardiac cycle phase where ventricles contract, AV valves close (S1), and ventricular pressure rises.

Ventricular ejection

Cardiac cycle phase where ventricular pressure exceeds arterial pressure and semilunar valves open.

Early ventricular diastole

Cardiac cycle phase where ventricles relax and semilunar valves close (S2).

Ventricular filling

Cardiac cycle phase where ventricular pressure falls below atrial pressure and AV valves open again.

Chronotropy

Effect on heart rate: positive chronotropy increases rate (faster), while negative chronotropy decreases rate (slower).

Inotropy

Effect on myocardial contractility: positive inotropy increases contractile force (stronger).

Dromotropy

Effect on cardiac conduction speed: positive dromotropy increases conduction speed (faster).

Baroreceptors

Sensory receptors located in the carotid region and aortic arch that sense changes in blood pressure.

Atropine

A medication that blocks vagal effects and can increase heart rate and AV conduction.

Stroke volume (SV)

The volume of blood ejected by a ventricle with each beat.

Heart rate (HR)

The frequency of cardiac contractions measured in beats per minute.

Cardiac output (CO)

The volume of blood pumped by one ventricle per minute, calculated as $\text{CO} = \text{SV} \times \text{HR}$.

Preload

The degree of ventricular filling and stretch prior to contraction.

Contractility

The intrinsic strength of myocardial contraction.

Afterload

The resistance or pressure that the ventricle must overcome to eject blood.

Frank-Starling mechanism

The physiological principle that increased ventricular filling stretches cardiac muscle, increasing the force of contraction within limits.

Ejection fraction

The fraction of end-diastolic ventricular volume ejected per beat.

Electrical axis

The overall direction of ventricular depolarization as represented on an ECG.