L6 - Heart Beat, Contractility and Conductivity

Blood Flow

Pathway of blood through heart chambers.

Pulmonary Circulation

Transports low oxygenated blood to lungs.

Systemic Circulation

Delivers highly oxygenated blood to body.

Pericardium

Protective sac surrounding the heart.

Epicardium

Outer layer of the heart wall.

Myocardium

Muscle layer responsible for heart contractions.

Endocardium

Inner lining of heart chambers.

Atrioventricular Valves

Valves between atria and ventricles.

Bicuspid Valve

Also known as the Mitral valve.

Tricuspid Valve

Right atrioventricular valve.

Semilunar Valves

Valves between ventricles and arteries.

Intercalated Disks

Connections between cardiac muscle fibers.

T Tubules

Conduct electrical impulses in muscle cells.

Sarcoplasmic Reticulum

Calcium storage for muscle contraction.

Sarcomere

Basic unit of muscle contraction.

Actin Filaments

Thin filaments involved in muscle contraction.

Myosin Filaments

Thick filaments providing mechanical force.

Sinoatrial Node

Primary pacemaker of the heart.

Atrioventricular Node

Secondary pacemaker, delays impulse transmission.

Bundle of His

Conducts impulses from AV node to ventricles.

Prepotential

Slow sodium influx before action potential.

Cardiac Cycle

Sequence of events in one heartbeat.

End Diastolic Volume (EDV)

Blood volume in ventricles before contraction.

End Systolic Volume (ESV)

Blood volume in ventricles after contraction.

Heart Failure

Inability of heart to meet body's demands.