EKG chapt. 1-3

What is epicardium?

Outermost layer of the heart. What colony arteries run through.

What is myocardium?

Middle layer of the heart. Thickest + pure muscle. The layer that suffers the most damage during a heart attack.

What is endocardium?

Innermost layer of the heart. Thinnest layer + forms lining if the heart and chambers and folds back in on itself to form valves.

What is the pericardium?

Double walked sack that encloses the heart. Bathed by pericardial fluid that bathes the heart.

What is the septum?

A muscular band of tissue that separates the right / left halves of the heart,

What is the interatrial septum?

Between the right and left atrium.

What is the interventricular septum?

Between the right/left ventricles.

What creates the heart sounds?

Lub (S1) & Dub (S2). S1 is the closure of AV valves, S2 is the closure of semilunar valves.

What is the cardiac cycle?

One complete heartbeat.

What is polarization?

Electrical charges are balanced, heart is at rest,

What is depolarization?

A contraction of the heart muscles aka, a beat. Release of electrical energy, inside of cells become more negative.

What is repolarization?

Muscle cells are returning to resting state, recharging.

What is a normal sinus rhythm?

60-100 bpm.

What is the range of a sinus tachycardic rhythm?

> 100 bpm.

What is a sinus bradycardia rhythm?

< 60 bpm.