Heart Retake
Select the correct statements about the function of myocardial cells.
The all-or-none law as applied to cardiac muscle means that the entire heart contracts as a unit or it does not contract all.
Which one of the following is caused by a decrease in venous return to the heart
a decrease in stroke volume and cardiac output
Hemorrhage with a large loss of blood causes
a lowering of blood pressure due tot change in cardiac output
Blood enters which of these vessels during ventricular systole?
aorta and pulmonary trunk
In which one of the following blood vessels is blood pressure the highest:
arteries
The path of blood flow within the systemic vascular system is:
arteries, arterioles, capillary beds, venules, veins
The P wave of a normal electrocardiogram indicates
atrial depolarization
Cardiac reserve
can be improved by regular exercie
Compared to skeletal muscle, cardiac muscle ____.
cells are larger than skeletal muscle cells
Normal heart sounds are caused by which of the following events
closure of the heart valves
The pericardial cavity
contains a lubricating fluid called serous fluid
If cardiac muscle is deprived of its normal blood supply, damage would primarily result from
decreased delivery of oxygen
The superior vena cava empties:
deoxygenated blood into the right atrium
When the ventricles contract, the bicuspid (mitral) valve prevents blood from flowing from the:
left ventricle to the left atrium
The thick layer of the heart wall that contains contractile cardiac muscle tissue is the
myocardium
When holding a dissected heart in your hands, it is easy to orient the right and left side by _______.
noticing the thickness of the ventricle walls
Which one of the following vessels receives blood during right ventricular systole::
pulmonary trunk
Which one of the following blood vessels carries oxygenated blood:
pulmonary vein
The left ventricular wall of the heart is thicker than the right wall in order to
pump blood with great pressure
The sinoatrial node is located in the:
right atrium
Which area of the heart receives blood from the systemic veins:
right atrium
The tricuspid valve is located between the
right atrium and right ventricle
Which one of the following represents the correct path for the transmission of an impulse in the intrinsic conduction system of the heart:
sinoatrial (SA) node, atrioventricular (AV) node, atrioventricular (AV) bundle, right and left bundle branches, Purkinje fibers
The volume of blood pumped out by each ventricle with each beat of the heart is called the:
stroke volume
A heart rate of over 100 beats per minute is called:
tachycardia
If the length of the absolute refractory period in cardiac muscle cells was the same as it is for skeletal muscle cells
tetanic contractions might occur, which would stop the heart's pumping action
The deflection waves in an ECG tracing include ______.
the T wave, which indicates ventricular repolarization
Which one of the following is true concerning the lub-dup sounds of the heart:
the first sound is longer and louder and is caused by closure of the AV valves; the second sound is shorter and sharper and is caused by closure of the semilunar valves
Which one of the following is the main function of renin and aldosterone:
they are produced whenever blood pressure falls and ultimately cause an increase in blood volume and blood pressure
Pulmonary Veins
transport oxygenated blood to the heart
The right AV valve is known as the
tricuspid valve
The aortic semilunar valve is composed of:
two cusps and closes when blood is filling the pulmonary circuit
The tricuspid valve is closed _____.
when the ventricle is in systole
The mitral valve is normally closed:
when the ventricle is in systolel
What structure divides the left from the right ventricle:
intraventricular septum
A person with a heart rate of 75 beats per minute and a stroke volume of 60 mL per beat has a cardiac output of:
4500 mL/minute
Cardiac output is about _____L/min.
5.25
The stroke volume for a normal resting heart is _____mL/beat.
70