Which statement does not accurately describe the pericardium?
C.
The pericardium is made up of a surface layer of mesothelium over a thin layer of connective tissue.
Which cardiac chamber has the thinnest wall and why?
a. The right and left atria; they are low-pressure chambers that serve as storage units
and conduits for blood.
b. The right and left atria; they are not directly involved in the preload, contractility,
or afterload of the heart.
c. The left ventricle; the mean pressure of blood coming into this ventricle is from the
lung, which has a low pressure.
d. The right ventricle; it pumps blood into the pulmonary capillaries, which have a
lower pressure compared with the systemic circulation.
A.
Which chamber of the heart endures the highest pressures?
C.
Pressure is greatest in the systemic circulation, driven by the left ventricle
What is the process that ensures mitral and tricuspid valve closure after the ventricles are
filled with blood?
A.
During ventricular relaxation, the two atrioventricular valves open and blood flows from the higher pressure atria to the relaxed ventricles. With increasing ventricular pressure, these valves close and prevent backflow into the atria as the ventricles contract.
Regarding the heart’s valves, what is a function of the papillary muscles?
D.
The papillary muscles are extensions of the myocardium that pull the cusps together and
downward at the onset of ventricular contraction, thus preventing their backward
expulsion into the atria.
During the cardiac cycle, why do the aortic and pulmonic valves close after the ventricles
relax?
D.
When the ventricles relax, blood fills the cusps and causes their free edges to meet in the
middle of the vessel, closing the valve and preventing any backflow.
The significance of the atrial kick is that it affects the contraction of the:
B.
Left atrial contraction, the atrial kick, provides a significant increase of blood to the left
ventricle.
Occlusion of the left anterior descending artery during a myocardial infarction would
interrupt blood supply to which structures?
A.
Occlusion of the circumflex artery during a myocardial infarction would interrupt blood
supply to which area?
D.
The circumflex artery often branches to the posterior surfaces of the left atrium and left ventricle.
The coronary ostia are located in the:
A.
Coronary arteries receive blood through openings in the aorta, called the coronary ostia
The coronary sinus empties into which cardiac structure?
B.
The cardiac veins empty only into the right atrium through the opening of a large vein called the coronary sinus.
What is the ratio of coronary capillaries to cardiac muscle cells?
C.
The heart has an extensive capillary network, with approximately 3300 capillaries per
square millimeter (ca/mm2) or approximately one capillary per one muscle cell (muscle
fiber).
During the cardiac cycle, which structure directly delivers action potential to the
ventricular myocardium?
C.
Each cardiac action potential travels from the SA node to the AV node to the bundle of His
(AV bundle), through the bundle branches, and finally to the Purkinje fibers and the
ventricular myocardium, where the impulse is stopped.
What causes depolarization of a cardiac muscle cell to occur?
B.
Phase 0 consists of depolarization, which lasts 1 to 2 milliseconds (ms) and represents rapid sodium entry into the cell.
Which event occurs during phase 1 of the normal myocardial cell depolarization and
repolarization?
C.
Phase 1 is early repolarization and the only time during which calcium slowly enters the
cell.
Which phase of the normal myocardial cell depolarization and repolarization correlates
with diastole?
B.
Potassium is moved out of the cell during phase 3, with a return to resting membrane potential only in phase 4. The time between action potentials corresponds to diastole.
Potassium is moved out of the cell during which phase of the normal myocardia depolarization and repolarization?
D.
A return to resting membrane potential in phase 4 of the myocardial depolarization and repolarization correlates with
D. diastole
In the normal electrocardiogram, what does the PR interval represent?
C.
The cardiac electrical impulse normally begins spontaneously in the sinoatrial (SA) node
because it:
C.
What period follows depolarization of the myocardium and represents a period during
which no new cardiac potential can be propagated?
B.
Which complex (wave) represents the sum of all ventricular muscle cell depolarizations?
C.
What can shorten the conduction time of action potential through the atrioventricular (AV)
node?
D.
If the sinoatrial (SA) node fails, then at what rate (depolarizations per minute) can the
atrioventricular (AV) node depolarize?
A.
What is the effect of epinephrine on beta 3 receptors on the heart?
D.
beta 3 receptors provide a safety mechanism that decreases myocardial contractility
Where in the heart are the receptors for neurotransmitters located?
A.
The beta 1 receptors are found mostly in the heart, specifically the conduction system (AV and SA nodes, Purkinje fibers) and the atrial and ventricular
myocardium
the beta 2 receptors are found in the heart and also on vascular smooth muscle.
Beta 3 receptors are also found in the myocardium and coronary vessels.
What enables electrical impulses to travel in a continuous cell-to-cell fashion in
myocardial cells?
A.
Only intercalated disks, thickened portions of the sarcolemma, enable electrical impulses to spread quickly in a continuous cell-to-cell
fashion.
Within a physiologic range, what does an increase in left ventricular end-diastolic volume
(preload) result in?
D.
This concept is expressed in the Frank-Starling law; the cardiac muscle, like other muscles, increases its strength of contraction when it is stretched
As stated in the Frank-Starling law, a direct relationship exists between the _____ of the
blood in the heart at the end of diastole and the _____ of contraction during the next
systole.
A.
Pressure in the left ventricle must exceed pressure in which structure before the left
ventricle can eject blood?
B.
Continuous increases in left ventricular filing pressures result in which disorder?
B.
Pressure changes are important because increased left ventricular filling pressures back up into the pulmonary circulation, where they force plasma out through vessel walls, causing fluid to accumulate in lung tissues (pulmonary edema).
When the volume of blood in the ventricle at the end of diastole increases, the force of the
myocardial contraction during the next systole will also increase, which is an example of
which law or theory about the heart?
D.
The Bainbridge reflex is thought to be initiated by sensory neurons in which cardiac
location?
C.
The Bainbridge reflex causes changes in the heart rate after intravenous infusions of blood or other fluid.
The changes in heart rate are thought to be caused by a reflex mediated by volume receptors found only in the atria that are innervated by the vagus nerve.
After the baroreceptor reflex is stimulated, the resulting impulse is transmitted from the
carotid artery by which sequence of events?
a. Vagus nerve to the medulla to increase parasympathetic activity and to decrease
sympathetic activity
b. Glossopharyngeal cranial nerve through the vagus nerve to the medulla to increase
sympathetic activity and to decrease parasympathetic activity
c. Glossopharyngeal cranial nerve through the vagus nerve to the medulla to increase
parasympathetic activity and to decrease sympathetic activity
d. Glossopharyngeal cranial nerve through the vagus nerve to the hypothalamus to
increase parasympathetic activity and to decrease sympathetic activity
C.
Neural impulses are transmitted over the glossopharyngeal nerve (ninth cranial nerve)
from the carotid artery and through the vagus nerve from the aorta to the cardiovascular
control centers in the medulla.
Reflex control of total cardiac output and total peripheral resistance is controlled by what
mechanism?
D.
Reflex control of total cardiac output and peripheral resistance includes
(1) sympathetic stimulation of the heart, arterioles, and veins
(2) parasympathetic stimulation of the heart only.
What is the most important negative inotropic agent?
B.
Chemicals affecting contractility are called inotropic agents. The most important negative inotropic agent is acetylcholine released from the vagus nerve.
The most important positive inotropic agents produced by the body are norepinephrine released from the sympathetic nerves that supply the heart and epinephrine released by the adrenal cortex
The right lymphatic duct drains into which structure?
B.
Where is the major cardiovascular center in the central nervous system?
D.
The major cardiovascular control center is in the brainstem in the medulla
What is an expected change in the cardiovascular system that occurs with aging?
D.
What is the major determinant of the resistance that blood encounters as it flows through
the systemic circulation?
C.
Which function of the cardiovascular system is often affected by ischemia?
D.
What physical sign is the result of turbulent blood flow through a vessel?
D.
Where flow is obstructed, the vessel turns or blood flows over rough surfaces. The flow becomes turbulent with whorls or eddy currents that produce noise, heard on auscultation
What is the major effect of a calcium channel blocker such as verapamil on cardiac
contractions?
D.
Which intracardiac pressure represents atrial contraction?
B.
Which intracardiac pressure reflects the rapid flow of blood from the great veins and right atrium into the right ventricle?
C.
Which intracardiac pressure may represent bulging of the mitral valve into the left atrium during early systole.
A.
An early diastole peak caused by filling of the atrium from peripheral veins is identified by
which intracardiac pressure?
B.
Which intracardiac pressure is produced because of the descent of the tricuspid valve ring
and by the ejection of blood from both ventricles?
C.
Which statement is false concerning the method in which substances pass between
capillaries and the interstitial fluid?
a. Substances pass through junctions between endothelial cells.
b. Substances pass through pores or oval windows (fenestrations).
c. Substances pass between vesicles by active transport across the endothelial cell
membrane.
d. Substances pass across the endothelial cell membrane by osmosis.
e. Substances pass through endothelial cell membranes by diffusion.
d
Relationship of wall tension, intraventricular pressure, internal radius, and wall thickness
Laplace’s law
During ventricular relaxation the two ___________ valves open and blood flows from the relatively higher pressure in the atria to the lower pressure in the relaxed ventricles
atrioventricular
The _______ valves of the heart open when intraventricular pressure exceeds aortic and pulmonary pressures.
semilunar
The coronary arteries originate just beyond the aortic semilunar valve cusps and receive blood through openings in the aorta called the ______ _______.
coronary ostia
The cardiac veins empty into the right atrium through another ostium, the opening of a large vein called the _______ ______.
coronary sinus
The _______ arteries are connections between branches of the coronary arteries
collateral
From the AV node, conducting fibers converge to form the __________ within the posterior border of the interventricular septum
bundle of His
_______ ______ extend from the ventricular apexes to the fibrous rings and penetrate the heart wall to the outer myocardium.
Purkinje fibers
___________, or the property of generating spontaneous depolarization to threshold, enables the SA and AV nodes to generate cardiac action potentials without any stimulus
Automaticity
force of myocardial contraction
inotropy
The effect of norepinephrine on _______ receptors is to inhibit release of more norepinephrine, which promotes vasodilation, thus providing another safety mechanism to prevent excess blood pressure elevation
alpha 2
_______ is the volume inside the ventricle at the end of diastole
Preload
________ is the resistance to ejection of blood from the left ventricle
afterload
The ___________ reflex is important in blood pressure control and is mediated by stretch receptors in the aortic arch and carotid arteries.
baroreceptor
__________ indicates that Blood flow is inversely related to resistance so that the greater the resistance in a vascular bed or tissue, the lower the blood flow
Poiseuille's law
During the period of systolic compression, when flow is slowed or stopped, oxygen is supplied by _________, a protein in heart muscle that binds oxygen during contraction and supplies oxygen to the myocardium
myoglobin
Author
BodeS
ID
362485
Card Set
CH. 32 Structure and Function of the Cardiovascular and Lymphatic Systems
Description
Structure and Function of the Cardiovascular and Lymphatic Systems
