Dynamic Study Modules - Sections 21.5 - 21.9

Place the steps of the cardiac cycle in order, from start to finish. 1. Ventricular diastole—early 2. Atrial systole begins 3. Ventricular diastole—late 4. Ventricular systole—second phase 5. Atrial systole ends, atrial diastole begins 6. Ventricular systole—first phase

2, 5, 6, 4, 1, 3

Place the steps in the movement of electrical impulses through the conducting system in order, from start to finish. Atrial contraction begins. There is a 100-millisecond delay at the AV node. The impulse is distributed by the Purkinje fibers and relayed throughout the ventricular myocardium. Atrial contraction is completed, and ventricular contraction begins. Depolarization spreads across the atrial surfaces and reaches the AV node. The impulse travels along the interventricular septum within the AV bundle and the bundle branches to the Purkinje fibers and, via the moderator band, to the papillary muscles of the right ventricle. SA node depolarization and atrial activation begin.

5, 3, 1, 4, 2

The major branches of the right coronary artery include which of the following?

All of the listed responses are correct.

Which of the following statements regarding the sinoatrial (SA) node is true?

Any factor that changes either the resting potential or the rate of spontaneous depolarization at the SA node will alter the heart rate.

Which valves of the heart do not have chordae tendineae?

Aortic and pulmonary semilunar valves

Which component of the conducting system of the heart slows the electrical impulse when it arrives from the internodal pathways?

Atrioventricular (AV) node

Which of the following statements regarding the cardiac cycle is false?

Blood will flow from a ventricle into the aorta or pulmonary trunk only as long as the semilunar valve is open, and arterial pressure exceeds ventricular pressure.

Which cranial nerve innervates the heart for parasympathetic control?

CN X

All of the following statements regarding cardiac muscle tissue are true, except:

Cardiac muscle cells are much larger than skeletal muscle fibers.

Which major branch of the left coronary artery curves to the left within the coronary sulcus, giving rise to one or more diagonal branches as it curves toward the posterior surface of the heart?

Circumflex branch

Which large coronary vein runs through the coronary sulcus, collects blood from most of the other coronary veins, and empties the blood directly into the right atrium?

Coronary sinus

Blood flows from the ascending aorta through the aortic arch into which of the following vessels?

Descending aorta

Which vessel(s) collect(s) blood from smaller veins draining the myocardial capillaries and deliver(s) this blood to the coronary sinus?

Great cardiac vein and middle cardiac vein

Regarding the conducting system of the heart, the signal for contraction passes from the sinoatrial node to the atrioventricular node via which of the following?

Internodal pathways

Which chamber of the heart contracts and sends blood into the pulmonary trunk?

Right ventricle

The autonomic centers for cardiac control are found in which area?

The cardiac centers of the medulla oblongata

All of the following are true of nodal cells, except:

The cell membranes of nodal cells depolarize only in response to neural stimulation.

Which of the following valves is found between the right atrium and the right ventricle?

Tricuspid valve

How many papillary muscles are normally found in the left ventricle?

Two

All of the following are true of heart attacks, except:

an infarct is an area that is undergoing PVCs (premature ventricular contractions).

The heart condition in which the atria contract in a coordinated manner, but the contractions occur very frequently, is called:

atrial flutter.

The opening in the interatrial septum of the heart, between the 5th week of embryonic development and birth, is called the:

foramen ovale.

All of the following blood vessels empty into the right atrium, except:

pulmonary veins.

Physical isolation of atrial muscle cells from ventricular muscle cells is a function of which of the following?

the cardiac skeleton