Trivia: The Cardiovascular System Quiz!

Cardiac muscle fibers are interconnected in branching networks that spread in all directions of the heart to form a ______ which is a mass of merging cardiac muscle cells.

The heart contains two functional syncytia. They are the _________ which is located in the atrial walls and the _______ which is located in the ventricular walls. If any part of the syncytium is stimulated, the whole structure contracts as a unit.

Except for a small region in the floor of the _______, the atrial syncytium is separated from the ventricular syncytium by the _______________.

The _________ is a network of specialized cardiac muscle cells that initiates and distributes electrical impulses.

Most of the specialized cardiac muscle cells involved in the cardiac conduction system are smaller than the _________ of the myocardium and contain fewer ________. Instead of contracting they initiate and distribute the _____________.

The fibers of the S-A node are continuous with those of the __________.

The S-A node is referred to as the _________ of the heart.

The S-A node contains pacemaker cells which establish the __________. It is responsible for the ________ of the heart.

As the cardiac impulse travels from the S-A node into the __________, the atria _______ almost simultaneously.

Junctional fibers have very _____ diameters that cause the impulses they carry to be ________.

The A-V node provides the only normal _____________ between the atrial and ventricular syncytia.

The ____________ does not conduct impulses and thus isolates the atrial myocardium from the ventricular myocardium.

The cells composing the A-V node are ______ efficient in conducting an impulse which causes a short delay in the transmission of the impulse to the_________.

Once the cardiac impulse reaches the distal end of the A-V node, it passes into a group of large fibers that make up the __________. This bundle is located in the superior portion of the ____________ where impulses travel __________.

The A-V bundle persists only briefly before dividing into the _____ and ______ bundle branches. These branches extend toward the _____ of the heart in the _________.

The bundle branches conduct the cardiac impulse to the ___________.

The purkinje fibers are very _____ fibers, essentially long strands of _____-shaped cells with few ______. They are located in the _________.

Purkinje fibers conduct impulses very _________; as fast as _____________.

The _______ is a mass of specialized cardiac muscle cells located in the lower right atrium near the entrance of the coronary sinus.

• S-A node

• Auricle

• A-V node

• Bundle branches

• Myofibril

The conduction system of the heart includes the _____ which is a small mass of specialized cardiac muscle cells situated on the posterior wall of the right atrium just below the opening of the superior vena cava beneath the epicardium.

• A-V node

• Pacemaker

• S-A node

• Atrial synctium

What is the importance of the A-V node?

• It permits the ventricles to complete their contraction and empty their blood into the pulmonary trunk and aorta

• It helps to close the A-V valves

• It has no real significance

• It permits the atria to complete their contraction and empty their blood into the ventricles before they contract

• It conducts electrical impulses to the purkinje fibers

The S-A node initiates one impulse after another _____ times per minute

• 50-60

• 60-70

• 70-80

• 80-90

• 90-100

_________ are fibers that are interspersed amongst the atrial muscle fibers that conduct the impulses to the A-V node.

• Purkinje fibers

• Myofibrils

• Contractile fibers

• Junctional fibers

• S-A fibers

Purkinje fibers complete the conduction pathway through the __________, penetrate into the _____ and then travel ____ into the __________. They give off many small paths and become continuous with the _____________.

The ventricular muscle fibers are arranged in patterns of _______. When these fibers are stimulated by the branches of the _______ , the ventricular walls contract with a _______ motion. The end result is that a ______ contraction of the ventricles begins at the _____ and pushes the blood _______ toward the ________. This effectively ejects some blood from the ventricles into the ____ and the _________.