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28 terms

A&P2 Heart- Ch20

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A heartbeat lasts
370 msec.
The left ventricle pumps blood to the
aorta
Most of the middle layer in the heart wall is composed of
cardiac myocytes
Contractions of the papillary muscles
prevent the atrioventricular valves from reversing into the atria
The first blood vessels to branch from the aorta are the ________ arteries.
coronary
The marginal branch and posterior interventricular branch are branches of the
right coronary artery
The cusps (leaflets) of atrioventricular valves attach directly to
chordae tendineae.
Blood flowing into the heart from the venae cavae flows next through the ________ valve.
tricuspid
In the middle of the thoracic cavity is a region occupied by the heart, great vessels, thymus, esophagus, and trachea called the
mediastinum.
Blood returning to the heart from the pulmonary circuit first enters the
left atrium.
The right ventricle pumps blood to the
right and left lungs.
When the left ventricle contracts, the distance from the apex to the base
decreases.
The bicuspid or mitral valve is located
between the left atrium and left ventricle.
The long plateau phase of the cardiac muscle action potential is due to
calcium channels remaining open.
The heart is innervated by ________ nerves.
both parasympathetic and sympathetic
The coronary sulcus is a groove that
marks the border between the atria and ventricles.
Contractions of the papillary muscles
prevent the atrioventricular valves from reversing into the atria
The visceral pericardium is the same as the
epicardium.
As blood leaves the right ventricle it passes through the ________ and then into the pulmonary trunk.
conus arteriosus
The first blood vessels to branch from the aorta are the ________ arteries.
coronary
The normal pacemaker of the heart is located in the
sinoatrial node.
The following are structural components of the conducting system of the heart.

1. Purkinje fibers
2. AV bundle
3. AV node
4. SA node
5. bundle branches

The sequence in which excitation would move through this system is
4, 3, 2, 5, 1.
The P wave of the electrocardiogram is a signal from
depolarization of the atria.
Depolarization of the ventricles is represented on an electrocardiogram by the
QRS complex
The volume of blood ejected from each ventricle during a contraction is called the
stroke volume
Drugs that block the beta-one adrenergic receptors will
decrease heart rate
The heart is roughly the size of
a man's clenched fist.
________ is to slow heart rate as ________ is to fast heart rate.
Bradycardia; tachycardia