Chapter 17 Test

During the period of ejection in the cardiac cycle, the atrioventricular valves are ___________, and the semilunar valves are ___________.

open, closed

Parasympathetic nerve fibers ____________.

result in an increased heart rate if stimulated

Which of these descriptions of the heart's location is correct?

the heart lies obliquely in the mediastinum

The epicardium is _________________.

the visceral pericardium

In an EKG, the P wave represents ______________.

Depolarization of the atria

Action potentials pass rapidly from one cardiac muscle cell to another because of the _____________.

Intercalated disks containing numerous gap junctions

The condition known as cardiac tamponade exhibits which of the following?

Interventricular septal opening

The second heart sound, described as "dub," is actually the sound of the _____________.

Semilunar valves closing

Blood flows neither into nor out of the ventricles during the ______________.

The periods of isovolumetric contraction & relaxation

The group of modified cardiac muscle cells that delays action potentials between the atria and the atrioventricular bundle is known as the ____________.

AV node

If the SA node is damaged and nonfunctional, which of these responses will most likely occur?

Another part of the heart, possibly the AV node, will become the pacemaker.

Unlike other cardiac muscle cells, the movement of _______ into the pacemaker cells is primarily responsible for the depolarization phase of the action potential.

Ca2+

At the end of __________, the ventricles are 70% filled.

Passive ventricular filling

Which of these conditions occurs in the cardiac muscle cell during the final repolarization phase?

Voltage-gated K+ ion channels are OPEN

Which of these statements about the heart is correct?

a &b -1. It is about the size of a fist2. It lies in the mediastinum

Soon after the onset of ventricular systole, the ________.

a and c

The valve located between the left atrium and left ventricle is the _______.

bicuspid (mitral) valve

Having one centrally located nucleus is a characteristic of ____________ cells.

cardiac muscle

Which of the following cells exhibits more mitochondria per cell?

cardiac muscle

Strong connective tissue strings attached to papillary muscles and to the cusps of the atrioventricular valves are known as the ___________.

chordae tendineae

The skeleton of the heart ______________.

electrically insulates the atria from the ventricles

The heart valves have a double layer of __________ with a layer of __________ in between.

endocardium; connective tissue

In heart failure, venous return is slowed. Edema results because _______.

venous pressure is increased