Chapter 19: Heart

The heart sounds "lub" and "dup" result from ________.

closure of heart valves

Oxygenated blood nourishing the myocardium comes from vessels that branch off the aorta called ________.

coronary arteries

Cardiac muscle cells differ from skeletal muscle fibers in that the cardiac muscle cells are uniquely interconnected by (the) ________.

intercalated discs

Select the correct statement about the heart valves.

The atrioventricular (AV) valves prevent backflow of blood added into the atria during ventricular contraction.

Blood leaves the left ventricle through an artery known as the ________.

aorta

An incompetent aortic semilunar valve would allow blood to backflow from the ________.

aorta to the left ventricle

Which valve is closed during heart relaxation to prevent blood from backflowing from the aorta into the heart?

aortic semilunar valve

The two superior receiving chambers of the heart are known as the ________, while the two inferior discharging chambers of the heart are known as the ________.

atria; ventricles

The first heart sound, "lub," is caused by the closure of the ________ valves.

atrioventricular (AV)

The transportation of blood from the right side of the heart to the lungs and back to the left side of the heart is known as ________ circulation.

pulmonary

Which heart structure receives blood from the systemic circuit?

right atrium

The tricuspid valve is located between the ________.

right atrium and right ventricle

Which valve is located between the right atrium and right ventricle?

tricuspid valve

What is the muscular layer of the heart wall?

myocardium

The walls of the ________ are substantially thicker because that chamber acts as the more powerful systemic pump of the heart.

left ventricle

Which of the following is often called the pacemaker of the heart?

sinoatrial (SA) node

You notice a missing P wave on a patient's electrocardiogram (ECG) and believe there is a problem with the ________.

sinoatrial (SA) node

Which one of the following represents the correct path for the transmission of an impulse in the intrinsic conduction system of the heart?

sinoatrial (SA) node, atrioventricular (AV) node, atrioventricular (AV) bundle (bundle of His), right and left bundle branches, Purkinje fibers

Which term means heart contraction?

systole

The mitral valve is normally closed ________.

when the ventricle is in systole