The heart has _ chambers
4
Which of the following is not important in preventing backflow of blood?
Endocardium
Which valve seperates the left atrium from the left ventricle?
Mitral
List valves in order through which the blood flows from the vena cava through the heart
Tricuspid, pulmonary semilunar, bicuspid, aortic semilunar
Which chamber initially recieves blood from the systemic circuit?
Right Atrium
The _ layer secretes chemicals that help to regulate ionic environments and strength of contraction and serve as powerful vasoconstrictors
Myocardium
The myocardium would be the thickest in the _
Left Ventricle
In which septum is it normal to find opening in the adult?
Atrioventricular septum
Which of the following is unique to cardiac muscle cells?
Only cardiac muscle is capable of autorythmicity
The influx of which ion accounts for the plateau phase
Calcium
Which portion of the ECG corresponds to repolarization of the atria
QRS complex
Which component of the heart conduction system would have the slowest rate of firing?
Purkinje fibers
The cardiac cycle consists of a distinct relaxation and contraction phase. Which term is typically used to refer to ventricular contraction while no blood is being ejected?
Isovolumic contraction
Most blood enters the ventricle during ________.
Atrial systole
The first heart sound represents which portion of the cardiac cycle?
Closing of the atrioventricular valves
Ventricular relaxation immediately follows
Ventricular repolarization
The force the heart must overcome to pump blood is known as
Afterload
the cardiovascular centers are located in which are of the brain?
Medulla Oblogonta
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?
There is no way to predict
Which of the following is a positive inotrope?
Ca2+
The earliest organ to form and begin function within the developing human is the ________.
Heart
Of the three germ layers that give rise to all adult tissues and organs, which gives rise to the heart?
Mesoderm
The two tubes that eventually fuse to form the heart are referred to as the ________.
Endocardial tubes
