Identify the three layers of the heart wall and describe the characteristics of each.

Question

 Identify the three layers of the heart wall and describe the characteristics of each.

Answer 1

The layers of the heart consist of the epicardium, myocardium, and endocardium. I like to break words down and "epi" means upon or on top of, "cardi" is heart and "ium" is compound or tissue, "myo" means muscle, and "endo" means inside.

The epicardium or top layer is the protective layer of the heart, and is responsible for protection and making pericardial fluid. It is composed of fat or adipose tissue, and loose connective tissue.

The myocardium, or muscle layer is the middle layer of the heart, which is responsible for the contraction of the heart, and is primarily composed of cardiac muscle fibers. This layer of the heart is also responsible for the conduction of the heart through the atrioventricular bundle and purkinje fibers, which carry electrical impulses for heart contraction.

The endocardium or innermost layer is composed primarily of smooth muscle and covers the innermost heart chambers and valves.The endocardium is the barrier between blood and the cardiac walls. The endocardium of the heart is continuous with the endothelium of large blood vessels.

Answer 2

1) Epicardium - Outer layer of the heart

1. Known as visceral pericardium
2. Made of loose connective tissue

2) Myocardium - Middle layer made of muscle

1. Important for heart contractions
2. Thickest layer

3) Endocardium - Inner layer

1. Covers heart valves
2. Made of smooth muscle