Cardiac Physiology and Anatomy Practice Flashcards

A comprehensive set of vocabulary flashcards covering the anatomy, physiology, electrical conduction, and cycle of the heart as described in the lecture notes.

Myocardium

Cardiac muscle tissue exclusive to the heart that exhibits autorhythmicity.

Autorhythmicity

The ability of cardiac muscle tissue to generate its own electrical impulses.

Myocardial contractile cells

Specific heart cells responsible for the actual pumping of blood.

Myocardial conducting cells

Specialized heart cells, including Purkinje cells, that transmit electrical impulses to coordinate contractions.

Intercalated discs

Specialized structures containing desmosomes and gap junctions that ensure synchronized contractions and strong connections between cardiomyocytes.

$Ca^{2+}$ (Calcium ions)

Ions essential for heart function that drive the refractory period and bind to troponin to allow cross-bridge formation.

Sinoatrial (SA) node

The starting point of the heart's electrical conduction pathway.

Cardiac conduction pathway

Sinoatrial node $\rightarrow$ atrioventricular node $\rightarrow$ atrioventricular bundle $\rightarrow$ bundle branches $\rightarrow$ Purkinje fibers.

Pacemaker potential

A gradual depolarization driven by sodium and calcium ion influx in conducting cells that leads to spontaneous rhythm.

Refractory period

A long period following depolarization in contractile cells that prevents premature contractions to ensure effective blood pumping.

Electrocardiogram (ECG/EKG)

A recording of the heart's electrical activity measured via surface electrodes.

P wave

The component of an ECG tracing representing atrial depolarization.

QRS complex

The component of an ECG tracing representing ventricular depolarization.

T wave

The component of an ECG tracing representing ventricular repolarization.

Systole

The period of the cardiac cycle characterized by contraction and blood ejection.

Diastole

The period of the cardiac cycle characterized by relaxation and chamber filling.

Cardiac Output (CO)

The volume of blood pumped per minute, calculated as $CO = HR \times SV$.

Stroke Volume (SV)

The amount of blood ejected with each beat, calculated as $SV = EDV - ESV$.

Medulla oblongata

The part of the brain containing cardiovascular centers that control sympathetic and parasympathetic stimulation of the heart.

Norepinephrine

The neurotransmitter released during sympathetic stimulation that increases heart rate ($HR$).

Acetylcholine

The neurotransmitter released during parasympathetic stimulation that decreases heart rate ($HR$).

Preload

The degree of stretch of the heart before contraction, determined by End-Diastolic Volume ($EDV$).

Frank-Starling mechanism

The principle stating that greater preload leads to stronger contractions and increased stroke volume ($SV$).

Afterload

The resistance the ventricles must overcome to pump blood, which increases with vasoconstriction.

Atherosclerosis

A condition characterized by the narrowing or blocking of coronary arteries due to plaque buildup, leading to Coronary Artery Disease (CAD).

Myocardial infarction

Commonly known as a heart attack, occurring when blood flow and oxygen supply to the heart are significantly reduced.

Bradycardia

A heart rhythm disorder characterized by an abnormally slow heart rate.

Tachycardia

A heart rhythm disorder characterized by an abnormally fast heart rate.

Angina pectoris

Chest pain resulting from reduced blood flow and oxygen supply to the heart muscle.