Cardiovascular Circuits and Electrical Activity

Vocabulary flashcards covering the two cardiovascular circuits, coronary circulation, the heart's conduction system, and ECG wave components.

Pulmonary circuit

The pathway of blood from the right atrium to the lungs to pick up oxygen and remove carbon dioxide, returning then to the left side of the heart.

Systemic circuit

The pathway of blood from the left side of the heart out to various tissues and organs (such as the brain, liver, and kidneys) and back to the right side of the heart.

Coronary arteries

The very first branch of the systemic circuit, originating from the aorta, which delivers oxygenated blood directly to the heart tissue.

Myocardium

The muscle tissue of the heart that requires a constant supply of oxygen and energy to function.

Coronary sinus

The vessel that receives blood from the cardiac veins and returns it to the right atrium.

Heart attack

The death of heart tissue that occurs when plaque builds up in the coronary arteries, preventing the myocardium from receiving necessary oxygen for a prolonged period.

Intrinsic stimulus

An electrical signal for contraction that is generated by the heart itself rather than being sent from the brain.

Sinoatrial (SA) node

Located at the top of the right atrium, it is known as the 'pacemaker of the heart' because it generates the electrical stimulus for heart contraction.

Intercalated disc

The junction between cardiac muscle fibers that allows an electrical impulse to spread rapidly across cells so they contract together.

Atrioventricular (AV) node

A node located at the base of the right atrium that receives the electrical signal from the atria before it travels down to the ventricles.

Atrioventricular (AV) bundle

Nervous tissue that carries the electrical signal down the middle of the heart between the right and left sides.

Purkinje fibers

Fibers at the end of the bundle branches that deliver the electrical signal to the ventricles, causing them to contract together.

Apex

The bottom tip of the heart where the bundle branches divide into Purkinje fibers.

Ectopic pacemaker

A random area of the heart outside the SA node that generates an inappropriate electrical signal, causing the heart to contract out of sync.

Ablation

A medical procedure to treat an ectopic pacemaker by burning the specific area of heart tissue causing the inappropriate firing.

Electrocardiogram (ECG)

A test that uses electrodes to monitor the collective electrical action potentials as they spread across the heart wall.

P wave

The component of an ECG wave that represents the depolarization of the atria.

QRS complex

The major spike on an ECG representing ventricular depolarization, which also masks the smaller signal of atrial repolarization.

T wave

The component of an ECG wave that represents the repolarization of the ventricles.