Chapter 19: Cardiovascular System: Heart (4) When Physiology Meets Pathology

Vocabulary flashcards covering key cardiovascular terms from the lecture notes, including concepts of cardiac output, regulation, preload/afterload, contractility, coronary circulation, heart failure, and valvular diseases.

Cardiac Output (CO)

A measure of how effectively the cardiovascular system fulfills its function—the amount of blood pumped by a single ventricle per minute (CO = HR × SV; ~5 L/min at rest in a healthy adult).

Ventricular Balance

The concept that the left and right ventricles eject equal volumes of blood to maintain balanced circulation.

Heart Rate (HR)

The number of heartbeats per minute (bpm).

Stroke Volume (SV)

The volume of blood ejected by a ventricle with each beat (mL/beat).

End-Diastolic Volume (EDV)

Volume of blood in the ventricle at the end of diastole (typical resting ~130 mL).

End-Systolic Volume (ESV)

Volume of blood remaining in the ventricle after contraction (typical ~60 mL).

Preload

Degree of stretch in the ventricles before contraction, determined by ventricular filling (EDV); more preload leads to a stronger contraction (Frank–Starling law).

Afterload

Resistance the ventricles must overcome to eject blood; major factor is arterial blood pressure; higher afterload reduces SV.

Contractility

The force of ventricular contraction at a given preload; increased by positive inotropes and decreased by negative inotropes.

Frank–Starling Law

The heart pumps what it receives: increased venous return increases preload and thus SV; excessive stretch can lead to heart failure; helps maintain ventricular balance.

Venous Return

Volume of blood returning to the heart via the veins; an important determinant of preload.

Positive Chronotropic Agents

Agents that increase heart rate by stimulating the SA and/or AV nodes (e.g., sympathetic stimulation, epinephrine, thyroid hormone, caffeine).

Negative Chronotropic Agents

Agents that decrease heart rate (e.g., parasympathetic activity via the vagus nerve, beta-blockers).

Positive Inotropes

Agents that increase contractility (e.g., sympathetic stimulation, epinephrine, digitalis).

Negative Inotropes

Agents that decrease contractility (e.g., acidosis, high potassium, calcium-channel blockers).

Cardiac Reserve

Maximal CO minus resting CO; the extra capacity the heart can recruit; athletes typically 4–5× resting CO; heart failure shows little or no reserve.

Atherosclerosis

Deposition of plaque in the inner lining of arteries, narrowing the diameter and increasing resistance, especially with aging.

Left Ventricular Hypertrophy (LVH)

Thickening of the left ventricular wall, typically due to chronic pressure overload (e.g., hypertension, aortic stenosis).

Systolic Heart Failure

Heart failure due to weak contraction with reduced ejection fraction.

Diastolic Heart Failure

Heart failure due to a stiff ventricle that impairs filling; ejection fraction may be preserved.

Pulmonary Edema

Fluid accumulation in the lungs due to left-sided heart failure; symptoms include shortness of breath, orthopnea, and pink frothy sputum.

Systemic Edema

Fluid accumulation in body tissues due to right-sided heart failure; including leg swelling and ascites.

Aortic Stenosis

Narrowing of the aortic valve causing LV hypertrophy and increased workload.

Mitral Regurgitation

Backflow of blood from the LV into the LA due to imperfect closure of the mitral valve, often with atrial dilation.

Mitral Stenosis

Narrowing of the mitral valve causing elevated left atrial pressure and pulmonary congestion.

Coronary Sinus

A venous channel that drains myocardial veins into the right atrium.

Left Anterior Descending (LAD) / Widowmaker

A branch of the left coronary artery (anterior interventricular) commonly referred to as the 'widowmaker' due to its infarction risk.

Left Coronary Artery (LCA)

Supplies the heart’s anterior surfaces via the LAD and circumflex branches.

Right Coronary Artery (RCA)

Supplies the right heart; gives rise to branches such as the right marginal and posterior interventricular arteries.