Electrical Current, EKG, Heart Study Guide

Primary function of the heart

Pumps blood throughout the body

Four chambers of the heart

Right atrium, right ventricle, left atrium, left ventricle

Chamber that pumps oxygenated blood

Left ventricle

Chamber that receives deoxygenated blood

Right atrium

Valve between left atrium and left ventricle

Mitral (bicuspid) valve

Valve between right atrium and right ventricle

Tricuspid valve

Function of heart valves

Prevents backflow of blood

Vessel carrying oxygenated blood away from heart

Aorta

Vessel carrying deoxygenated blood to lungs

Pulmonary arteries

Septum of the heart

Divides heart; prevents mixing of oxygenated and deoxygenated blood

Natural pacemaker of the heart

SA node

If SA node fails

AV node takes over (slower heart rate)

Location of SA node

Right atrium

Role of AV node

Delays impulse and sends it to ventricles

Structure from AV node to ventricles

Bundle of His (AV bundle)

Function of Purkinje fibers

Distribute electrical impulses to ventricles causing contraction

What triggers ventricular contraction

Electrical impulses

Depolarization

Electrical activation causing contraction

Repolarization

Recovery phase after contraction

What EKG measures

Electrical activity of the heart

P wave

Atrial depolarization

QRS complex

Ventricular depolarization

T wave

Ventricular repolarization

Normal EKG rhythm

Regular repeating P wave, QRS complex, T wave

Normal blood pressure

120/80

Low blood pressure

90/60 (hypotension)

Hypertensive crisis

Severely high blood pressure (≈180/120+)

Mitral valve prolapse

Valve does not close properly

Coronary artery disease

Blocked heart arteries

Ventricular tachycardia

Dangerously fast heart rhythm

Atrial fibrillation

Irregular heartbeat