Chapter 17
End- diastolic volume for each ventricle during rest is normally about
120 ml
Place the following parts of the cardiac conduction system in the order in which they transmit the action potential
3,6,1,4,2,5
Calculate the end-systolic volume (ESV) if the end-diastolic volume (EDV) in a resting heart is 110 ml and stroke volume (SV) is 70 ml.
40 ml
Stroke volume averages about
70 ml per heart beat
which vessel supplies the systemic circuit with oxygenated blood?
AOrta
Predict the position of the valves when the ventricles contract.
Both AV valves are forced shut while both semilunar valves are forced open
A damaged AV bundle or AV node will primarily affect the length of the __________________
P-R interval
During what part of the action potential will calcium ions enter the contractile cell?
Plateau phase
Blood that leaves the right ventricle enters the __________.
Pulmonary Trunk
On an electrocardiogram atrial depolarization is obscured by the
QRS wave
Which wave of the ECG represents ventricular depolarization?
QRS wave
Which of the following can be used to measure heart rate?
R-R interval
The main pacemaker of the heart is the
SA node
The right and left atria depolarize and contract following the arrival of the action potential from the:
SA node
The volume of blood pumped by each ventricle in one heartbeat is known as
Stroke volume
What two values are needed in order to calculate cardiac output (CO) for a ventricle?
Stroke volume (SV) and Heart rate (HR)
What best describes the Frank- Starling law?
The Frank-Starling law states that the more the ventricular muscle cells are stretched, the more forcefully they contract.
Which of the following decreases heart rate?
acetylcholine
The right and left coronary arteries receive blood from the :
aorta
Where should the left ventricle send blood?
aorta
The P wave on the ECG represents the depolarization of cells in the __________
atria
Which hormone decreases cardiac output by decreasing blood volume and preload?
atrial natriuretic peptide
Autorhythmicity is the responsibility of:
cardiac pacemaker cells
The cusps of the atrioventricular valves attach directly to:
chordae tendineae
Inotropic agents affect:
contractility
Coronary veins empty into vessels known as the
coronary sinus
The right side of the heart receives
deoxygenated blood from the systemic circuit
What largely determines preload?
end-diastolic volume (EDV)
The visceral pericardium is also known as the _______
epicardium
Which opening in the interatrial septum of the fetal heart connects the right and left atrium?
foramen ovale
High pressured blood in the ventricles:
forces the semilunar valves open
The apex if the heart is
inferior
What characteristic differentiates cardiac muscle cells
intercalated disc
Blood returning from the lungs enter the
left atrium
Which chamber experiences a maximum pressure of around 118 mm Hg during contraction?
left ventricle
the cardiac with the thickest ventricle is
left ventricleTe
What muscles, present in the ventricles, anchor by tendon like chords called chord tendineae
papillary muscle
The degree of stretch by the sarcomeres in the ventricle cells before they contract
preload
The aortic valve closes when __________.
pressure in the left ventricle falls below aortic pressure
The AV valves close when
pressure in the ventricles increases
What is the function of the valves in the heart
prevent back flow of blood in the heart
Which vessel is guarded by a semilunar valve at its base?
pulmonary trunk
Which of the following does NOT return blood to the right atrium of the heart
pulmonary vein
What vessel deliver oxygenated blood to the left atrium
pulmonary veins
What valve prevents the back flow of blood from the right ventricle into the right atrium
right atrioventricular valve (tricuspid)
Which two arteries arise from the right coronary artery?
right marginal artery and right posterior interventricular artery
Archie has a resting heart rate of 125 beats per minute. Classify his cardiac dysrhythmia
tachycardia
What produces the "Lub dub" heart sounds?
the vibrations of the ventricular and blood vessel walls when valves shut
Blood in the right atrium should travel next past the
tricuspid valve and into the right ventricle
Which cranial nerves have a negative chronotropic effect on heart rate?
vagus nerve
Both the left and right atria receive blood from:
veins
Blood from the systemic circuit returns to the heart via the __________.
vena cave
the chambers that have just emptied when the second heart sound is heard are the
ventricles
The T wave of an ECG corresponds to _________
ventricular repolarization