Study Guide: Cardiac Physiology

A collection of flashcards covering the anatomical structure and function of the heart, including electrical activity, blood flow pathways, and physiological responses.

Right atrium

The chamber of the heart that receives used blood from the body.

Pulmonary circuit

The pathway of blood flow from the heart to the lungs and back to the heart for gas exchange.

Na+ (sodium)

An ion that slowly leaks in, helping to drift toward the threshold in autorhythmic action potentials.

Epinephrine

A hormone that increases heart rate.

Cardiac cycle

The sequence of events in one heartbeat, including atrial contraction and ventricular relaxation.

Frank-Starling Law

States that the more blood enters the heart, the stronger the contraction of the heart muscle.

Absolute Refractory Period

The period in which cardiac muscle cannot contract again, ensuring a safe rhythm.

Isometric contraction

A type of muscle contraction where tension builds but the muscle does not shorten.

Digitalis

A drug that increases the strength of heart contractions and slows heart rate by blocking the Na/K pump.

Mitral valve (bicuspid)

The valve between the left atrium and left ventricle.

T wave

The part of the ECG that represents the relaxation (repolarization) of the ventricles.

Atrial fibrillation

A heart condition characterized by chaotic atrial signals leading to irregular heartbeats.

Autorhythmic Cells

Self-firing heart cells that generate their own electrical impulses to maintain the heartbeat.

Tachycardia

A condition where the heart rate is too fast.

Lub Dub sounds

The sounds of the heart produced by the closure of valves during the cardiac cycle.

Intercalated discs

Structures that provide electrical connections between cardiac muscle cells.

ECG

Electrocardiogram, a recording of the electrical activity of the heart.

Bundle of His

A group of heart muscle cells that transmit the electrical impulse from the atria to the ventricles.

Aorta

The large artery that carries oxygenated blood from the left ventricle to the body.

Calcium blockers

Medications that decrease heart rate and contraction strength.

Skeletal muscle tension

The ability of skeletal muscle to increase tension through recruitment of fibers and increased frequency.