Blood within the pulmonary veins returns to the ________.
left atrium
The condition where fluid compresses the heart and limits its ability to contract is called ________.
cardiac tamponade
A foramen ovale ________.
fossa ovalis
Which of the events below does not occur when the semilunar valves are open?
Ventricles are in diastole
Compared to skeletal muscle, cardiac muscle ________.
has gap junctions that allow it to act as a functional syncytium
Norepinephrine acts on the heart by ________.
causing threshold to be reached more quickly
Select the correct statement about the function of myocardial cells.
The entire heart contracts as a unit or it does not contract at all.
Which of these vessels receives blood during ventricular systole?
both the aorta and pulmonary trunk
If cardiac muscle is deprived of its normal blood supply, damage would primarily result from ________.
decreased delivery of oxygen
Damage to the ________ is referred to as heart block.
AV node
The source of blood carried to capillaries in the myocardium would be the ________
coronary arteries
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 fact that the left ventricle of the heart is thicker than the right ventricle reveals that it ________.
pumps blood against a greater resistance
During the period of ventricular filling ________.
blood flows passively through the atria and the open AV valves into the ventricles
Select the correct statement about the heart valves.
The AV valves are supported by chordae tendineae so that regurgitation of blood into the atria during ventricular contraction does not occur.
The left ventricular wall of the heart is thicker than the right wall in order to ________.
pump blood with greater pressure
Normal heart sounds are caused by which of the following events?
closure of the heart valves
Hemorrhage with a large loss of blood causes ________.
a lowering of blood pressure due to change in cardiac output
To auscultate the aortic semilunar valve, you would place your stethoscope in the ________.
second intercostal space to the right of the sternum
When viewing a dissected heart, it is easy to visually discern the right and left ventricles by ________.
noticing the thickness of the ventricle walls
Which of the choices below does not explain why low capillary pressures are desirable?
Low blood pressure is associated with longer life span than high blood pressure.
Which of the following is not one of the three main factors influencing blood pressure?
emotional state
Select the correct statement about factors that influence blood pressure.
Excess red cell production would cause a blood pressure increase.
Secondary hypertension can be caused by ________.
arteriosclerosis
In the dynamics of blood flow through capillaries, hydrostatic pressure ________.
is the same as capillary blood pressure
Histologically, the ________ is squamous epithelium supported by a sparse connective tissue layer.
tunica intima
The arteries that directly feed into the capillary beds are called ________.
arterioles
Select the correct statement about blood flow.
Blood flow through the entire vascular system is equivalent to cardiac output.
The arteries that are also called distributing arteries are the ________.
muscular arteries
Which of the following would not result in the dilation of the feeder arterioles and opening of the precapillary sphincters in systemic capillary beds?
a local increase in pH
Mechanisms that do not help regulate blood pressure include ________.
the dural sinus reflex
Factors that aid venous return include all except ________.
urinary outputs
Where in the body would you find low oxygen levels causing vasoconstriction and high levels causing vasodilation?
lungs
Which of the following do not influence arterial pulse rate?
the vessel selected to palpate
Which of the following blood pressure readings would be indicative of hypertension?
170/96 in a 50-year-old man
The pulse pressure is ________.
systolic pressure minus diastolic pressure
Blood flow to the skin ________.
increases when environmental temperature rises
Which of the following is the most significant source of blood flow resistance?
blood vessel diameter
The short-term controls of blood pressure, mediated by the nervous system and bloodborne chemicals, primarily operate via all but which of the following?
altering blood volume
Permitting the exchange of nutrients and gases between the blood and tissue cells is the primary function of ________.
capillaries