77 terms

Fellah A&P II Chapter 18 Heart

The myocardium receives its blood supply from the coronary arteries
Cardiac muscle has more mitochondria and depends less on a continual supply of oxygen than does skeletal muscle
False - Does depend on oxygen
Anastomoses among coronary arterial branches provide collateral routes for blood delivery to the heart muscle
Congestive heart failure means that the pumping efficiency of the heart is depressed so that there is inadequate delivery of blood to body tissues
Tissues damaged by myocardial infarction are replaced by connective tissue
The left side of the heart pumps the same volume of blood as the right
Chronic release of excess thyroxine can cause a sustained increase in heart rate and a weakened heart
Arterial blood supply to heart muscle is continuous whether the heart is in systole or diastole
False - It's intermittent
Trabeculae carneae 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 - It's the DUB sound
Autonomic regulation of heart rate is via two reflex centers found in the pons
False - It's found in the medulla
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 - The AV Flaps are closed
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
Proxysmal atrial tachycardia is characterized by bursts of atrial contractions with little pause between them
Normal heart sounds are caused by which of the following events?
Closure of the heart valves
Which of the events below does not occur when the semilunar valves are open?
Ventricles are in diastole
Hemorrhage with a large loss of blood causes_____
a lowering of blood pressure due to chance in cardiac output
The left ventricular wall of the heart is thicker than the right wall in order to ________
pump blood with a greater pressure
Damage to the _________ is referred to as heart block
AV Node
The P wave of a normal electrocardiogram indicates ________
atrial depolarization
Blood within the pulmonary veins returns to the ________
left atrium
Small muscle masses attached to the chordae tendineae are the ________
papillary muscles
The term for pain associated with deficient blood delivery to the heart that may be caused by the transient spasm of coronary arteries is ________
angina pectoris
To auscultate the aortic semilunar valve, you would place your stethoscope in the ________
second intercostal space to the right of the sternum
The source of blood carried to capillaries in the myocardium would be the ________
coronary arteries
The fact that the left ventricle of the heart is thicker than the right ventricle reveals that it ________
pumps blood against a greater resistance
Which of the following factors does not influence heart rate?
skin color
Which of the following is not an age-related change affecting the heart?
thinning of the valve flaps
If cardiac muscle is deprived of its normal blood supply, damage would primarily result from ________
a decreased delivery of oxygen
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
Norepinephrine acts on the heart by ________
causing threshold to be reached more quickly
If the vagal nerves to the heart were cut, the result would be that ________
the heart rate would increase by about 25 beats per minute
Foramen ovale ________
connects the two atria in the fetal heart
Which vessel of the heart receives blood during right ventricular systole?
pulmonary trunk
Which of these vessels receives blood during ventricular systole?
both the aorta and pulmonary trunk
Which of the following is not part of the conduction system of the heart?
AV valve
The tricuspid valve is closed ________
when the ventricle is in systole
When viewing a dissected heart, it is easy to visually discern the right and left ventricles by _______
noticing the thickness of the ventricle walls
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
Select the correct statement about the function of myocardial cells
The entire heart contracts as a unit or it does not contract at all
Select the correct statement about the structure of the heart wall
The myocardium is the layer of the heart that actually contracts
Compared to skeletal muscle, cardiac muscle ________
has gap junctions that allow it to act as a functional syncytium
During the period of ventricular filling ________
blood flows passively through the atria and the open AV valves into the ventricles
The second heart sound is heard during which phase of the cardiac cycle?
isovolumetric relaxation "DUB"
The time of day most hazardous for heart attacks is ________
If we were able to artificially alter the membrane permeability of pacemaker cells so that sodium influx is more rapid, ________
threshold is reached more quickly and heart rate would increase
Select the correct statement about cardiac output
A slow heart rate increases end diastolic volume, stroke volume, and force of contraction
During contraction of heart muscle cells ________
some calcium enters the cell from the extracellular space and triggers the release of larger amounts of calcium from intracellular stores
Isovolumetric contraction ________
refers to the short period during ventricular systole when the ventricles are completely closed chambers
Commotio cordis is heart failure due to a ________
relatively mild blow to the chest that occurs during a vulnerable interval (2 ms) when the heart is repolarizing
The enlarged coronary vessel outside the heart that empties blood into the right atrium is the _____
Coronary Sinus
What structure in the fetal heart allows blood to flow from the right atrium directly to the left atrium?
Foramen Ovale
The ECG T wave interval represents ________
Ventricular Repolarization
CO = ________ × SV
The ________ membrane covers the heart
Visceral Pericardium OR Epicardium
The ________ valve of the heart has three valves with chordae tendineae
The ___________ and _____________ valves of the heart have no chordae tendineae attached
Aortic and Pulmonary Semilunar
The inner lining of the heart
Heart muscle
Serous layer covering the heart muscle
The outermost layer of the serous pericardium
parietal layer
The pacemaker of the heart
SA Node
Found in the interventricular septum
AV Bundle
Network found in the ventricular myocardium
purkinje fibers
The point in the conduction system of the heart where the impulse is temporarily delayed
AV Node
Prevents backflow into the left ventricle
aortic valve
Prevents backflow into the right atrium
tricuspid valve
Prevents backflow into the left atrium
mitral valve
Prevents backflow into the right ventricle
pulmonary valves
AV valve with two flaps
mitral valve
AV valve with three flaps
tricuspid valve
Heart muscle is deprived of oxygen
Death of heart muscle cells
A condition of rapid and irregular or out-of-phase contraction of heart muscle cells
An abnormal pacemaker
Ectopic focus
Total heart relaxation
Quiescent period