The Cardiovascular System

Vocabulary practice flashcards covering cardiovascular anatomy, cardiac cycle phases, hemodynamics, regulatory reflexes, vasculature, and clinical conditions.

Cardiovascular System

An organ system consisting of the heart, blood, and blood vessels that functions to transport oxygen, nutrients, hormones, and waste, while regulating temperature, pH, and fluid balance.

Mediastinum

The central compartment of the thoracic cavity between the lungs, located slightly left of the midline, where the heart is anatomically positioned.

Base of the Heart

The superior, broad portion of the heart located at the level of the 3rd costal cartilage.

Apex of the Heart

The inferior tip of the heart, formed primarily by the left ventricle, situated to the left of the sternum between the 4th and 5th intercostal spaces; serves as the apical pulse site.

Pericardium

A fluid-filled sac surrounding and protecting the heart; composed of an outer tough fibrous pericardium and an inner serous pericardium consisting of parietal and visceral layers.

Epicardium

The outermost layer of the heart wall, identical to the visceral layer of the serous pericardium.

Myocardium

The middle and thickest layer of the heart wall, composed predominantly of cardiac muscle cells responsible for pumping blood.

Endocardium

The deepest layer of the heart wall, composed of endothelial tissue that lines the internal chambers and valves.

Cardiac Tamponade

A clinical condition where excess fluid accumulates in the pericardial space, compressing the heart and impeding normal ventricular relaxation and filling.

Right Atrium

The heart chamber that receives deoxygenated blood returning from the systemic circulation via the superior and inferior vena cava.

Right Ventricle

The chamber that receives blood from the right atrium and pumps deoxygenated blood to the lungs through the pulmonary valve and pulmonary arteries.

Left Atrium

The heart chamber that receives oxygenated blood directly from the lungs via the pulmonary veins.

Left Ventricle

The thickest-walled heart chamber, which pumps oxygenated blood under high pressure through the aortic valve into the aorta for systemic distribution.

Pulmonary Circuit

The circulatory pathway carrying deoxygenated blood from the right ventricle to the lungs for gas exchange, and returning oxygenated blood to the left atrium.

Systemic Circuit

The circulatory pathway transporting oxygen-rich blood from the left ventricle through arteries to body tissues, and returning deoxygenated blood back to the heart.

Coronary Arteries

Arteries that originate from the aortic root just superior to the aortic valve and deliver oxygen-rich blood directly to the myocardium.

Left Coronary Artery (LCA)

Coronary blood vessel supplying the left atrium, left ventricle, and interventricular septum; branches into the circumflex artery and the anterior interventricular artery (LAD).

Right Coronary Artery (RCA)

Coronary blood vessel supplying the right atrium, portions of both ventricles, and the cardiac conduction system; branches into marginal arteries and the posterior interventricular artery.

Tricuspid Valve

The right atrioventricular valve composed of three endothelial leaflets that prevents backflow of blood from the right ventricle into the right atrium during systole.

Pulmonary Valve

A semilunar valve located at the base of the pulmonary trunk, formed of three flaps that prevent blood from flowing backward into the right ventricle.

Mitral Valve

The left atrioventricular (bicuspid) valve featuring two cusps (anterior medial and posterior medial) that prevents backflow from the left ventricle into the left atrium.

Aortic Valve

A semilunar valve containing three flaps situated at the base of the aorta, preventing the retrograde flow of blood into the left ventricle.

Valve Auscultation Sites

Specific chest surface locations used to listen to individual heart valves: aortic (2nd intercostal right), pulmonic (2nd intercostal left), tricuspid (lower left sternal border), and mitral (5th intercostal left midclavicular line).

Cardiomyocytes

Striated, involuntary cardiac muscle cells characterized by short, branching morphology, a single central nucleus, and abundant mitochondria.

Myocardial Contractile Cells

Specialized cardiomyocytes constituting approximately $99\%$ of the heart muscle, responsible for generating the contractile force needed to pump blood.

Myocardial Conducting Cells

Specialized cells comprising approximately $1\%$ of the myocardium that generate and transmit electrical action potentials throughout the heart in a coordinated pattern.

Sinoatrial (SA) Node

A cluster of specialized nodal cells in the superior wall of the right atrium that acts as the primary physiological pacemaker, self-generating impulses at $60\text{--}100\,\text{bpm}$.

Atrioventricular (AV) Node

Conducting tissue in the inferior portion of the interatrial septum that delays the electrical impulse to permit complete atrial emptying and ventricular filling.

Systole

The phase of the cardiac cycle defined by myocardial contraction during which the chambers actively pump blood outward.

Diastole

The phase of the cardiac cycle defined by myocardial relaxation, allowing the cardiac chambers to fill with incoming blood.

S1 (Lub)

The first normal heart sound, produced by the closure of the atrioventricular (tricuspid and mitral) valves at the onset of ventricular systole.

S2 (Dub)

The second normal heart sound, produced by the closure of the semilunar (aortic and pulmonary) valves at the onset of ventricular diastole.

S3 Heart Sound

An abnormal heart sound (termed the 'Kentucky gallop') caused by rapid ventricular inflow or tensing of chordae tendineae; often indicates heart failure when auscultated in older adults.

S4 Heart Sound

An abnormal heart sound (termed the 'Tennessee gallop') caused by vigorous atrial contraction into a hypertrophic or stiff ventricle; indicates left ventricular failure if heard prior to S1.

Heart Murmur

An atypical sound produced by turbulent blood flow across cardiac valves, graded on a severity scale from $1$ to $6$.

Cardiac Output (CO)

The volume of blood pumped by each ventricle in one minute, determined by the formula: $CO = HR \times SV$.

Stroke Volume (SV)

The volume of blood ejected by a ventricle per heartbeat, calculated as end-diastolic volume minus end-systolic volume ($SV = EDV - ESV$), averaging roughly $70\,\text{mL}$.

Systolic Blood Pressure

The maximum peak arterial pressure exerted during active ventricular contraction.

Diastolic Blood Pressure

The minimum baseline arterial pressure measured while the ventricles are relaxed in diastole.

Pulse Pressure

The numerical difference between systolic and diastolic blood pressures.

Baroreceptor Reflex

A homeostatic neural reflex mechanism initiated by stretch receptors in the carotid sinuses and aortic arch that signals the medulla oblongata to rapidly stabilize arterial pressure.

Tunics

The three structural tissue layers forming the walls of blood vessels: the inner tunica intima, the muscular middle tunica media, and the supportive outer tunica externa.

Arterioles

Small resistance branches of arteries with tunica media smooth muscle capable of altering vessel diameter to regulate local tissue perfusion and systemic blood pressure.

Capillaries

Microscopic, single-endothelial-cell thick microvessels that permit the diffusion and exchange of gases, nutrients, and waste products between blood and interstitial fluid.

Venules

Small vascular vessels that collect blood leaving capillary networks and channel it into larger systemic veins.

Arterial Pulse Palpation Sites

Superficial arteries accessible for palpation, including the temporal, facial, common carotid, brachial, radial, femoral, popliteal, posterior tibial, and dorsalis pedis arteries.

Aorta

The largest systemic artery, emerging from the left ventricle and terminating at the 4th lumbar vertebra where it divides into the common iliac arteries.

Brachiocephalic Artery

The first major branch arising from the aortic arch that subsequently divides into the right subclavian and right common carotid arteries.

Circle of Willis

An arterial anastomosis at the base of the brain supplied by the internal carotid and vertebral arteries that provides collateral and uninterrupted cerebral blood flow.

Foramen Ovale

An anatomical shunt in the fetal heart allowing oxygenated blood to cross directly from the right atrium to the left atrium, bypassing non-functional lungs.

Ductus Arteriosus

A fetal vascular shunt connecting the pulmonary trunk directly to the aorta to redirect blood away from the pulmonary circuit.

Ductus Venosus

A temporary fetal vessel that shunts oxygenated umbilical blood away from the liver directly into the inferior vena cava toward the heart.

Coronary Artery Disease (CAD)

A cardiovascular condition marked by atherosclerotic plaque buildup within coronary arteries, reducing myocardial perfusion and potentially causing angina or infarction.

Hypertension

A persistent chronic elevation of systemic arterial blood pressure that damages blood vessels and increases the workload of the heart.

Arrhythmias

Disorders of the cardiac electrical conduction system causing abnormal heart rates or rhythms, categorized as bradycardia, tachycardia, or fibrillation.