Cardiovascular Medicine I Flashcards

Comprehensive vocabulary flashcards covering cardiovascular anatomy, conduction systems, cellular physiology, and pathophysiology based on the Module I lecture notes.

Ascending aorta

A large, elastic vessel situated centrally within the heart that recoils after filling to generate onwards arterial flow.

Brachiocephalic trunk

The first aortic branch which gives rise to the left and right carotid arteries and the right subclavian artery.

Pulmonary veins

Vessels that carry oxygenated blood from the lungs back to the left atrium of the heart.

Left atrium

The low-pressure receiving chamber for oxygenated blood returning from the pulmonary circulation.

Left auricle

A blind-ending pouch on the cranio-lateral aspect of the left atrium that represents the embryologic left atrium.

Left ventricle

The heart’s primary pump that forms the cardiac apex and is responsive to changes in atrial filling, arterial resistance, and autonomic tone.

Aortic valve

A valve in fibrous continuity with the mitral valve that is critical for maintaining systemic arterial pressure and tissue perfusion.

Mitral valve

A bicuspid atrioventricular valve that prevents back-flow of blood into the left atrium during ventricular systole.

Papillary muscles

Myocardial projections that tense the valve leaflets before peak systole to brace against increasing pressure.

Chordae tendinae

Major and minor fibrous cords that attach the atrioventricular valve leaflets to the papillary muscles.

Coronary ostia

Openings located in the sinuses of Valsalva, immediately beyond the aortic valve, that lead to the left and right coronary arteries.

Left subclavian artery

The second aortic branch which supplies the left thoracic limb and some vertebral arteries.

Bronchial veins

Systemic vessels that perfuse lung tissue and empty into the pulmonary veins, contributing a small amount of de-oxygenated blood to systemic circulation.

Interventricular septum

The muscular wall between the ventricles which contributes to right ventricular systolic function and curves towards the right due to higher left-sided pressures.

Thebesian veins

Small veins that empty directly into the heart cavities, representing a portion of the heart's own venous drainage.

Cranial vena cava

The vessel providing venous drainage from the head, neck, and thorax to the right atrium.

Caudal vena cava

The vessel providing venous drainage from the abdomen and caudal body to the right atrium.

Azygous vein

A vessel draining the dorsal walls of the abdomen and thorax which forms an anastomosis between the cranial and caudal vena cavae.

Right atrium

A confluence of the cranial and caudal vena cavae that empties through the tricuspid valve.

Right ventricle

A low-pressure, U-shaped conduit between the systemic veins and the pulmonary artery that wraps around the cranial aspect of the left heart.

Tricuspid valve

A three-leaflet atrioventricular valve whose anatomy can be highly variable between dogs.

Pulmonic valve

A three-leaflet semilunar valve that is anatomically separate from the other valves lying within the fibrous annulus of the heart.

Ligamentum arteriosum

A remnant of the foetal ductus arteriosus that tethers the pulmonic bifurcation to the ventral aspect of the descending aorta.

Coronary sinus

An orifice on the floor of the right atrium representing the entrance of the great cardiac vein and coronary venous drainage.

Intervenous tubercle

A muscular ridge on the posterior right atrial wall that streams blood flow from the cranial vena cava toward the tricuspid orifice.

Fossa ovalis

The site of the embryologic foramen ovale, appearing as a thin, fibrous region in the inter-atrial septum.

Sino-atrial node

The primary pacemaker of the heart located in the high right atrium wall.

Atrioventricular (AV) node

A region of naturally slow conduction on the floor of the right atrium that allows the atria to prime the ventricles before ventricular contraction.

Fibrous AV annulus

A structure that electrically isolates the atria from the ventricles, except at the AV node.

Purkinje fibres

The tiny, terminal branches of the cardiac conduction pathways.

Gap junctions

Membrane structures that allow electrical impulses to travel via a cell-to-cell pathway after leaving the Purkinje fibres.

Resting membrane potential

The electrical charge of a cardiomyocyte at rest, which is approximately $-80\,mV$.

Escape foci

Lower order pacemakers in the hierarchy that serve as backups when the sinoatrial node is dysfunctional or AV block occurs.

T-tubules

Invaginations of the cell surface membrane that facilitate rapid depolarisation and reduce the distance calcium ions travel to reach intracellular structures.

Sarcoplasmic reticulum

A highly folded series of membranous sacs that acts as a storehouse for calcium ions within the cardiomyocyte.

L-type calcium channel

A voltage-gated channel that allows an influx of calcium into the cytosol from the extracellular space during depolarisation.

CICR (Calcium-induced calcium release)

Also called the Ryanodine receptor, this protein opens when activated by calcium to release large amounts of calcium from the sarcoplasmic reticulum.

SERCA2a pump

An ATP-dependent pump that actively moves calcium ions from the cytosol back into the sarcoplasmic reticulum.

Sodium-calcium exchanger (NCX)

A passive, two-way channel on the cell surface membrane that exchanges sodium for calcium based on concentration gradients.

Sarcomere

The microscopic apparatus of the cardiomyocyte composed of actin and myosin that causes physical contraction.

Troponin complex

A group of three proteins (including Troponin C and I) that regulates the binding of myosin heads to actin based on calcium concentration.

Cross-bridge

The bond formed when myosin heads flip inwards and attach to the active binding sites of actin, shortening the sarcomere.

Blood pressure equation

$$\text{Blood pressure} = (\text{cardiac output}) \times (\text{systemic vascular resistance})$$

Cardiac output equation

$$\text{Cardiac output} = (\text{stroke volume}) \times (\text{heart rate})$$

Baroreceptor reflex

A mechanism that provides rapid alterations (seconds to hours) to vascular resistance and cardiac output to maintain cerebral perfusion.

RAAS (Renin-Angiotensin-Aldosterone System)

A neurohormonal system activated by reduced renal blood flow that increases preload and afterload to maintain blood pressure.

Preload

The volume of blood returning to the heart, which increases during chronic RAAS activation.

Afterload

The systemic vascular resistance the heart must pump against, which is increased by vasoconstriction.

Systolic dysfunction

Muscular weakness, as seen in dilated cardiomyopathy, causing reduced stroke volume and drop in cardiac output.

Diastolic dysfunction

Impaired cardiac filling due to myocardial stiffness and a smaller ventricular lumen, as seen in hypertrophic cardiomyopathy.

Concentric hypertrophy

Cardiomyocytes laid down in parallel, causing thickening of the myocardium in response to pressure overload.

Eccentric hypertrophy

Cardiomyocytes laid down in series, causing increased chamber diameter and wall thinning (dilation) in response to volume overload.