A&P 2 Chapter 20 HW

An action potential in cardiac contractile cells is the same as an action potential in skeletal muscle cells EXCEPT for

the presence of a plateau phase in cardiac contractile cells

The long plateau phase of the cardiac muscle action potential is due to

calcium channels remaining open

In cardiac muscle, the fast depolarization phase of the action potential is the result of

increased membrane permeability to sodium ions

Rupture of the papillary muscles in the left ventricle may result in

mitral valve prolapse

Each of the following factors will increase cardiac output except increased

parasympathetic stimulation

Coronary veins empty into the

right atrium

What feature allows the blood supply to the heart muscle to remain relatively constant regardless of the pressure changes in the coronary arteries due to heartbeats?

arterial anastomoses

The property of heart muscle to contract in the absence of neural or hormonal stimulation is called

automaticity

Activation of which kind of receptor causes heart rate to increase?

beta-one

Part complete The amount of blood pumped by the left ventricle in one minute during the cardiac cycle is called the

cardiac output

The cusps (leaflets) of atrioventricular valves attach directly to

chordae tendinae

As blood leaves the right ventricle, it passes through the ________ and then into the pulmonary trunk.

conus arteriosus

A procedure in which a length of the patient's vein or artery is used to create a detour around an obstruction in a coronary artery is called

coronary artery bypass graft

When a blood clot forms on a ruptured plaque in a coronary artery, the condition is referred to as a(n)

coronary thrombosis

The amount of blood remaining in the ventricle when the semilunar valve closes is the

end-systolic volume

Blood returning to the heart from the pulmonary circuit first enters the

left atrium

An MI that affects the ________ side of the heart is more severe because it has to pump blood with ________ force.

left;more

Contractions of the papillary muscles

prevent the atrioventricular valves from reversing into the atria.

Blood leaves the right ventricle by passing through the

pulmonary valve

Stroke volume depends on all of the following factors except

respiratory rate

Blood returning to the heart from the systemic circuit first enters the

right atrium

The phase in the cardiac cycle when the mitral valve is closed and the aortic valve is open is the

systolic ejection phase

Blood is supplied to the myocardium by

the coronary arteries

If the connection between the SA node and AV node becomes blocked,

the ventricles will beat more slowly

Muscular ridges on the inner surface of the ventricles are calledt

trabeculae carneae

________ is when the heart can't maintain adequate cardiac output.

Heart failure

If the force of ventricular contraction increases, what will happen to the end-systolic volume?

decrease

Part complete Which of the following describes what is directly measured by an ECG?

electrical conduction

The ________ is the volume of blood in a ventricle at the beginning of systole.

end-diastole volume

The ________ is the amount of blood in a ventricle after it has contracted and before it begins to refill.

end-systolic volume

Tetanic muscle contractions don't occur in a normal cardiac muscle because

the refractory period lasts until the muscle relaxes

The normal pacemaker of the heart is located in

the sinoatrial node

Cardiac cells damaged by infarction will show all of the following except

an increase in metabolic activity