Heart Wall

Intercalated discs

Each cardiac muscle fiber connects with other fibers in the networks by thickenings of the sarcolemma (plasma membrane) called ____. a) discs b) intracalated discs c) intercalated discs

True

True or False: Cardiac muscle fibers form two separate networks - one atrial and one ventricular.

Endocardium

What is the innermost layer of the heart wall? It is a thin layer of simple squamous epithelium that lines the inside of the myocardium and covers the valves of the heart and the tendons attached to the valves. It is continuous with the epithelial lining of the blood vessels. a) epicardium b) myocardium c) endocardium

Myocardium

What is the middle layer of the heart wall? It consists of cardiac muscle tissue, which constitutes the bulk of the heart. This tissue is found only in the heart and is specialized in structure and function. It is responsible for the pumping action of the heart. Cardiac muscle fibers (cells) are involuntary, striated, and branched, and the tissue is arranged in interlacing bundles of fibers. a) epicardium b) myocardium c) endocardium

Epicardium

What is the outermost/external layer of the heart wall? It is also known as the visceral layer of the serous pericardium. It is thin, transparent and the outer layer of the wall. It is composed of mesothelium and connective tissue. a) epicardium b) myocardium c) endocardium

gap junctions

Within the discs are _____ that allow action potentials to conduct from one cardiac muscle to the next. a) gap junctions b) tight junctions c) adhering junctions