CHAPTER 19 The Cardiovascular System: The Heart

which of the following is a positive inotrope?

Ca2+

The force the heart must overcome to pump blood is known as ________.

afterload

Most blood enters the ventricle during ________.

atrial diastole

in which septum is it normal to find openings in the adult?

atrioventricular septum

Which primitive area of the heart will give rise to the right ventricle?

bulbs cordis

the influx of which ions accounts for the plateau phase?

calcium

The two tubes that eventually fuse to form the heart are referred to as the ________.

cardiogenic tubes

the first heart sound represents which portion of the cardiac cycle?

closing of the atrioventricular valves

the_______ layer secrets chemicals that help to regulate ionic environments and strength of contraction and serve as powerful vasoconstrictor

endocardium

which of the following is not important in preventing back flow of blood?

endocardium

The earliest organ to form and begin function within the developing human is the ________.

heart

The cardiac cycle consists of a distinct relaxation and contraction phase. Which term is typically used to refer ventricular contraction while no blood is being ejected?

isovolumic contraction

In a healthy young adult, what happens to cardiac output when heart rate increases above 160 bpm?

it decreases

what happens to preload when there is venous constriction in the veins?

it increases

the myocardium would be the thickest in the

left ventricle

the cardiovascular centers are located in which are of the brain?

medulla oblongata

Of the three germ layers that give rise to all adult tissues and organs, which gives rise to the heart?

mesoderm

Which valve separates the left atrium from the left ventricle?

mitral

which of the following is unique to the cardiac muscle cells?

only cardiac muscle is capable of autorythmicity

which portion of the heart conduction system would have the slowest rate of firing?

purkinge fibers

Which chamber initially receives blood from the systemic circuit?

right atrium

which of the following lists the valves in the order through which the blood flows from the vena cava through the heart?

tricuspid, pulmonary semilunar, bicuspid, aortic semilunar

the pulmonary trunk and aorta are derived from which primitive heart structure?

truncus arteriosus

Ventricular relaxation immediately follows ________.

ventricular repolarization