The sequence of pericardial layers from superficial to deep is the fibrous, ________, and
visceral pericardium.

parietal

The right atrium receives blood from the superior vena cava, inferior vena cava, and
________.

coronary sinus

A heart valve that fails to close properly is considered to be ________ or to exhibit
insufficiency.

incompetent

Irregular ridges in the walls of the ventricles are called ________.

trabeculae carneae

The walls of the ________ are thicker so as to push blood through the systemic circuit.

left ventricle

The ________ valve prevents backflow of blood from the left ventricle to the left atrium.

mitral, left atrioventricular, or bicuspid

The atrioventricular valves cannot be inverted because attachment of ________.

chordae tendineae

The first heart sounds of "lub-dup" are produced by the closing of the right and left ________.

atrioventricular valves

The ________ of the heart prevents overdilation of the valve openings.

cardiac skeleton

The ________ are subdivisions of the atrioventricular bundle located within the upper half of
the interventricular septum.

bundle branches or crura

The ________ artery supplies the left atrium and the posterior part of the left ventricle.

circumflex artery

Gap junctions and fasciae adherens are associated with ________ that join adjacent cardiac
muscle cells.

intercalated disks

Uncoordinated contractions of the ventricle, known as ________, result from irregularities in
conducting system behavior.

fibrillation