Cardiovascular System Physiology and Heart Anatomy Flashcards

A set of 40 vocabulary flashcards covering cardiovascular system physiology, heart anatomy, pericardial structure, cardiac cycle phases, ECG basics, and fetal circulation.

Pulmonary Circuit

The circulatory route that moves blood from the right ventricle through the pulmonary arteries to the lungs for oxygenation and carbon dioxide removal, and returns it via the pulmonary veins to the left atrium.

Systemic Circuit

The circulatory route that pumps oxygenated blood from the left ventricle through the aorta to body tissues and returns deoxygenated blood via the veins and venae cavae to the right atrium.

Atrioventricular (AV) Valves

Valves located between the atria and ventricles, consisting of the tricuspid valve on the right and the bicuspid or mitral valve on the left, which prevent backflow into the atria during ventricular contraction.

Semilunar Valves

Valves located between the ventricles and major outflow arteries, consisting of the pulmonary valve leading to the pulmonary trunk and the aortic valve leading to the aorta.

Chordae Tendineae

Tendinous cords attaching the cusps of AV valves to papillary muscles, helping to prevent valve prolapse into the atria during ventricular systole.

Desmosomes

Cellular structures within intercalated discs that provide strong mechanical linkage between neighbouring cardiac muscle cells.

Gap Junctions

Protein channels within intercalated discs that allow electrical current to spread rapidly between adjacent cardiac muscle cells.

Functional Syncytium

A tissue structure resulting from electrical coupling via gap junctions that enables the atria to contract together as one unit and the ventricles to contract together as another unit.

Autorhythmic Cells

Specialised cardiac muscle cells comprising about $1\%$ of the heart cells that initiate and conduct action potentials to set the heart rhythm rather than producing main pumping force.

Contractile Cells

Cardiac muscle cells comprising about $99\%$ of the heart cells that perform the mechanical work of pumping in response to electrical signals.

Sinoatrial (SA) Node

The normal pacemaker of the heart located in the upper right atrial wall, having an intrinsic firing rate of about $70\text{--}80$ action potentials per minute.

Atrioventricular (AV) Node

A node in the conduction system that delays impulse transmission so atrial contraction can complete before ventricular contraction begins, possessing an escape rhythm of about $40\text{--}60\text{ beats/min}$.

Plateau Phase

The prolonged period during a contractile cell action potential where $Ca^{2+}$ influx balances $K^+$ efflux, extending the refractory period and preventing tetanic contraction.

P Wave

The ECG trace deflection representing atrial depolarisation.

QRS Complex

The ECG trace wave structure representing ventricular depolarisation, within which atrial repolarisation is hidden.

T Wave

The ECG trace deflection representing ventricular repolarisation.

First Heart Sound ('lub')

The sound produced by the closure of the atrioventricular (AV) valves at the onset of ventricular systole.

Second Heart Sound ('dub')

The sound produced by the closure of the semilunar valves at the onset of ventricular diastole.

End-Diastolic Volume (EDV)

The total volume of blood present in a ventricle at the end of its filling phase.

End-Systolic Volume (ESV)

The volume of blood remaining in a ventricle after ejection has occurred.

Cardiac Output (CO)

The volume of blood pumped by one ventricle per minute, calculated as $\text{CO} = \text{HR} \times \text{SV}$ with a typical resting value of about $5\,L/min$.

Stroke Volume (SV)

The volume of blood ejected by one ventricle in a single beat, calculated as $\text{SV} = \text{EDV} - \text{ESV}$ with a typical resting value of about $70\,mL/beat$.

Vessel Radius

The primary determinant of vascular resistance, where even minor changes significantly alter blood flow.

Atherosclerosis

A cardiovascular condition characterized by plaque accumulation that narrows and stiffens arteries, leading to reduced blood flow.

Angina Pectoris

Chest pain resulting from reduced coronary blood flow and myocardial ischemia.

Myocardial Infarction

Permanent damage to heart muscle caused by prolonged ischemia, commonly referred to as a heart attack.

Fibrous Pericardium

The outer, tough coat of dense connective tissue in the pericardial sac that adheres to the diaphragm inferiorly and prevents heart overfilling.

Serous Pericardium

A double-layered membrane composed of an outer parietal layer lining the fibrous pericardium and an inner visceral layer (epicardium) adhering to the heart wall.

Pericardial Cavity

The potential slit-like space between the parietal and visceral layers of serous pericardium that contains pericardial fluid to reduce friction.

Pericardiocophrenic Artery

A branch of the internal thoracic artery (ITA) that provides the primary blood supply to the pericardium.

Phrenic Nerve

The nerve that provides sensory innervation to the pericardium.

Crista Terminalis

An internal vertical ridge in the right atrium that separates the smooth-walled area from the rough area containing pectinate muscles.

Pectinate Muscles

Vertical muscular ridges located on the anterior internal wall of the right atrium and within the auricles.

Fossa Ovalis

An oval depression on the interatrial septum representing the remnant of the fetal foramen ovale.

Trabeculae Carneae

Projecting muscular ridges found on the internal wall surfaces of the right and left ventricles.

Conus Arteriosus

The smooth, conical outlet of the right ventricle that leads directly into the pulmonary trunk.

Foramen Ovale

A fetal interatrial opening that allows blood to flow directly from the right atrium to the left atrium, bypassing non-functional fetal lungs.

Ductus Arteriosus

A fetal vascular shunt between the pulmonary trunk and the aortic arch that closes after birth to become the ligamentum arteriosum.

Coronary Sinus

A large venous channel on the posterior surface of the heart that receives blood from cardiac veins and empties into the right atrium.

Great Cardiac Vein

A coronary vein running alongside the anterior interventricular artery that drains blood from areas supplied by the left coronary artery into the coronary sinus.