The myocardium receives its blood supply from the coronary arteries. |
TRUE |
Cardiac muscle has more mitochondria and depends less on a continual supply of oxygen than does skeletal muscle. |
FALSE |
Congestive heart failure means that the pumping efficiency of the heart is depressed so that there is inadequate delivery of blood to body tissues. |
TRUE |
Tissues damaged by myocardial infarction are replaced by connective tissue. |
TRUE |
The left side of the heart pumps the same volume of blood as the right. |
TRUE |
Chronic release of excess thyroxine can cause a sustained increase in heart rate and a weakened heart. |
TRUE |
Arterial blood supply to the heart muscle is continuous whether the heart is in systole or diastole. |
FALSE When the ventricles contract and push the Semilunar Valves open the coronary artery is closed. |
Trabeculae carnae are found? |
in the ventricles and never the atria. |
The "lub" sounds of the heart are valuable in diagnosis because they provide information about the function of the heart’s pulmonary and aortic valves. |
FALSE |
Autonomic regulation of heart valve is via two reflex centers found in the pons. |
FALSE |
The papillary muscles contract after the other ventricular muscles so that they can take up the slack on the chordae tendineae before the full force of ventricular contractions sends blood against the AV valve flaps. |
FALSE |
As pressure in the aorta rises, more ventricular pressure is required to open the aortic valve. |
TRUE |
What is tachycardia |
bursts of atrial contractions with little pause between them. |
Which of the events below does not occur when the semilunar valves are open? |
Ventricles are in Diastole |
The fact that the left ventricle of the heart is thicker than the right ventricle reveals that it ________. pumps a greater volume of blood |
Pumps Blood against a greater resistance |
Which is correct? |
The AV valves are supported by chordae tendineae so that regurgitation of blood into the atria during ventricular contraction does not occur. |
The term for pain associated with deficient blood delivery to the heart that may be caused by the transient spasm of coronary arteries is ________. myocardial infarct |
angina pectoris |
The source of blood carried to capillaries in the myocardium would be the _______ |
coronary arteries |
Blood within the pulmonary veins returns to the ________. |
left atrium |
which is correct? –Connective tissue in the heart wall aids in the conduction of the action potential. |
The myocardium is the layer of the heart that actually contracts. |
Small muscle masses attached to the chordae tendineae are the ________. |
papillary muscles |
When viewing a dissected heart, it is easy to visually discern the right and left ventricles by ________. |
noticing the thickness of the ventricle walls |
The left ventricular wall of the heart is thicker than the right wall in order to ________. |
pump blood with greater pressure |
The heart is actually (one, two, or three) pumps? |
two pumps |
Which chamber receives blood from the superior and inferior vena cavae? |
right atrium |
Which heart chamber receives blood from the pulmonary veins? |
left atrium |
Which heart chamber pumps unoxygenated blood out the pulmonary trunk? |
right ventricle |
Which chamber pumps oxygenated blood out the aorta to the systemic circuit? |
left ventricle |
Select the correct statement about the function of myocardial cells in a healthy, normally functioning heart.
–The influx of potassium ions from extracellular sources is the initiating event in cardiac muscle contraction. |
The atria, followed by the ventricles, contract as a unit or they do not contract at all. |
During contraction of heart muscle cells ________. –calcium is prevented from entering cardiac fibers that have been stimulated |
some calcium enters the cell from the extracellular space and triggers the release of larger amounts of calcium from intracellular stores |
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 |
tetanic contractions might occur, which would stop the heart’s pumping action |
Compared to skeletal muscle, cardiac muscle ________. |
has gap junctions that allow it to act as a functional syncytium |
Cardiac muscle has more mitochondria and depends less on a continual supply of oxygen than does skeletal muscle |
false |
If cardiac muscle is deprived of its normal blood supply, damage would primarily result from ________. |
decreased delivery of oxygen |
which is true about cardiac output –If a semilunar valve were partially obstructed, the end systolic volume in the affected ventricle would be decreased. |
A slow heart rate increases end diastolic volume, stroke volume, and force of contraction. |
The second heart sound is heard during which phase of the cardiac cycle? |
isvolumetric relaxation |
The tricuspid valve is closed ________. –when the ventricle is in systole |
when the ventricle is in systole |
Normal heart sounds are caused by which of the following events? |
Closing of the heart Valves |
If the vagal nerves to the heart were cut, the result would be that ________. the AV node would become the pacemaker of the heart |
the heart rate would increase by about 25 beats per minute |
Damage to the ________ is referred to as heart block. |
AV Node |
Which vessel of the heart receives blood during right ventricular systole? |
Pulmonary Trunk |
During the period of ventricular filling ________. the P wave on the ECG has the peak |
Blood passively flows through the atria and the open AV valves into the ventricles. |
The time of day most hazardous for heart attacks is ________. |
Morning |
If we were able to artificially alter the membrane permeability of pacemaker cells so that sodium influx is more rapid, ________. heart rate would decrease, but blood pressure would rise due to the excess sodium present |
threshold is reached more quickly and heart rate would increase |
Tissues damaged by myocardial infarction are replaced by connective tissue. |
True |
Norepinephrine acts on the heart by ________. |
Causing the threshold to be reached more quickly |
Hemorrhage with a large loss of blood causes ________. |
a lowering of blood pressure due to change in cardiac output |
Which of the following is not part of the conduction system of the heart? AV valve |
AV Valve |
Isovolumetric contraction ________. |
refers to the short period during ventricular systole when the ventricles are completely closed chamber |
Which of these vessels receives blood during ventricular systole? aorta only |
both the aorta and pulmonary trunk |
An ECG provides direct information about valve function. |
False – ECG is a composite of all the action potentials generated by nodal and contractile cells at any given time |
As pressure in the aorta rises due to atherosclerosis, more ventricular pressure is required to open the aortic valve. |
true |
The P wave of a normal electrocardiogram indicates ________. |
atrial depolarization |
what is congestive heart failure? |
The pumping efficiency of the heart is depressed so that there is inadequate delivery of blood to body tissues. |
Is the Pulmonary trunk an artery or a vein? |
ARTERY |
Does the pulmonary truck carry oxygen rich or oxygen poor blood? |
oxygen poor |
Where are arteries connected to? |
Ventricles |
where are veins connected to? |
atrium |
The coronary sinus drains blood to the Left or Right atrium |
Right atrium |
Why does the coronary sinus drain blood to the right atrium and not the left? |
Because it is still apart of the systemic system. |
When is blood pumped into the coronary arteries? |
When the aortic Semilunar valve is closed and the ventricle is in diastole |
Papillary muscles function to |
adjust tension of the chordae tendinae |
which of the following has the thickest wall |
Left ventricle |
which vessle is in contact with myocardium |
Loos areolar connective tissue |
which of the following vessels contains oxygenated blood? Inferior vena cava |
pulmonary veins |
What is the structure between right ventricle and pulmonary trunk? |
pulmonary semilunar valves |
What is the conduction pathway in the heart |
SA node AV node Atrioventricular bundle L&R bundle branches purkinje fibers |
During the cardiac cycle, the amount of blood ejected from the left ventricle when the semilunar valve opens is the |
Stroke Volume |
Which of the following is longer? |
The refractory period of cardiac muscle |
if the papillary muscles fail to contract |
None of these |
when the semilunar valves are opened which of the following are occuring? coronary arteries fill |
AV valves are closed Ventricles are in Diastole Blood enters aorta |
AV node is located on |
Right atrium |
The major ion channel which is responsible for the plateau phase of the contractile cell action potential is |
Voltage gated SLOW Ca++ Channels |
Cardiac cells are communicated with each other via |
gap junctions |
How does the Parasympathetic nervous system affect the Heart rate? |
ACH opens ligand gated K+ channels longer to reach threshold slowed heart rate |
What major ion channel is responsible for the depolarization phase of the action potential of the conducting cells? |
FAST voltage gated Ca++ channels |
How does the Sypmathetic nervous system affect the heart rate? |
NE opens more ligand gated Na+ channels faster to reach threshold heart rate inclease |
What does the P wave represent? |
Atrial contraction |
What does the QRS complex represent |
ventricular contraction |
What does the T wave represent? |
ventricular relaxation |
Tachycardia |
>100 beats/min short T-P interval |
Bradychardia |
<60 beats/min longer R-R |
Mitral Stenosis |
valve is leaking, blood backflow, extra wide P wave |
Atrial Fibrillation |
no P wave Decreased pumping effectiveness |
Ventricular fibrillation |
No QRS missing rythym or pattern |
Marieb Chapter 18 The heart A&P 2
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