______ carry oxygen-poor blood
Venae cavae and pulmonary arteries
_______ belong to the pulmonary circuit
Pulmonary arteries and pulmonary veins
_______ is the most superficial layer enclosing the heart
Pericardial fluid is found between
the parietal and visceral membranes
The _____ performs the work of the heart
The tricuspid valve regulates the opening between
the right atrium and right ventricle
Oxygen-poor blood passes through
the right AV (tricuspid) valve and pulmonary valve
Opening and closing of the heart valves is caused by
After entering the right atrium, the furthest a red blood cell can travel is the
superior vena cava
Obstructions of the ______ will cause a more severe myocardial infarction(MI) than the obstruction of any of the others.
left coronary artery (LCA)
Cardiac muscle shares this feature with skeletal muscle
cardiac muscle fibers have striations
The ______ is the pacemaker that initiates each heart beat
sinoatrial (SA) node
Which of these is not part of the cardiac conduction system
the tendinous cords (TC)
These are features of cardiac muscle fibers except
they have about the same endurance as skeletal muscle fibers
This is the correct path of an electrical excitation from the pacemaker to a cardiocyte in the left ventricle (LV)
sinoatrial (SA) node - atrioventricular (AV) node - atrioventricular (AV) bundle- Purkinje fibers - cardiocyte in LV
The pacemaker potential is a result of
The plateau in the action potential of cardiac muscle results from the action of
slow Ca+ channels
Cells of the sinoatrial node _____ during the pacemaker potential
Any abnormal cardiac rhythm is called a
If the sinoatrial (SA) is damaged, the heart will likely beat at
40 to 50 bpm
The ______ provides most of the Ca2+ needed for myocardial contraction
Atrial systole begins
immediately after the P wave.
Atrial depolarization causes
the P wave
The long plateau in the action potential observed in cardiocytes is probably related with _____ staying longer in their cytosol
The long absolute refractory period of cardiocytes
When the left ventricle contracts, the____ valve closes and the _____ valve is pushed open
Mitral valve stenosis causes blood to leak back into the _____ when the ventricle contract
Isovolumetric contraction occurs during the ______ of the electrocardiogram.
During the isovolumetric contraction, the pressure in the ventricles
Mitral valve prolapse (MVP) generates a murmur associated with the _____ heart sound that occurs when the _____
lubb (SI); ventricles contract
This is the correct sequence of events of the cardiac cycle
ventricular filling - isovolumetric contraction - ventricular ejection - isolvolumetric relaxation
Most of the ventricle filling occurs
during the atrial diastole
Congestive heart failure (CHF) of the right ventricle
can cause systemic edema
Assume that the left ventricle of a child's heart has an EDV= 90mL, and ESV= 60mL, and a cardiac output of 2,400mL/min. His SV and HR are
SV= 30mL/beat, HR= 80 bpm.
_____ increases stroke volume
Increased venous return
The volume of blood ejected by each ventricle in one minute is called
the cardiac output
Cardioinhibitory centers in the ____ receive input from ______
medulla oblongata; chemoreceptors in the aortic arch
The Frank- Starling law of the heart states that stroke volume is proportional to
the end-diastolic volume
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