Marieb Chapter 18 The heart A&P 2
The second heart sound is heard during which phase of the cardiac cycle?
isvolumetric relaxation
Chronic release of excess thyroxine can cause a sustained increase in heart rate and a weakened heart.
TRUE
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
The left side of the heart pumps the same volume of blood as the right.
TRUE
The myocardium receives its blood supply from the coronary arteries.
TRUE
Tissues damaged by myocardial infarction are replaced by connective tissue.
TRUE
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 pericarditis angina pectoris ischemia
angina pectoris
The P wave of a normal electrocardiogram indicates ________.
atrial depolarization
where are veins connected to?
atrium
The source of blood carried to capillaries in the myocardium would be the _______
coronary arteries
Cardiac cells are communicated with each other via
gap junctions
Compared to skeletal muscle, cardiac muscle ________.
has gap junctions that allow it to act as a functional syncytium
Trabeculae carnae are found?
in the ventricles and never the atria.
Small muscle masses attached to the chordae tendineae are the ________.
papillary muscles
What is the structure between right ventricle and pulmonary trunk?
pulmonary semilunar valves
which of the following vessels contains oxygenated blood? Inferior vena cava superior vena cava pulmonary arteries pulmonary veins
pulmonary veins
The left ventricular wall of the heart is thicker than the right wall in order to ________.
pump blood with greater pressure
Isovolumetric contraction ________.
refers to the short period during ventricular systole when the ventricles are completely closed chamber
Which chamber receives blood from the superior and inferior vena cavae?
right atrium
Which heart chamber pumps unoxygenated blood out the pulmonary trunk?
right ventricle
During contraction of heart muscle cells ________. --calcium is prevented from entering cardiac fibers that have been stimulated -- the action potential is initiated by voltage-gated slow calcium channels --the action potential is prevented from spreading from cell to cell by gap junctions --some calcium enters the cell from the extracellular space and triggers the release of larger amounts of calcium from intracellular stores
some calcium enters the cell from the extracellular space and triggers the release of larger amounts of calcium from intracellular stores
The heart is actually (one, two, or three) pumps?
two pumps
Mitral Stenosis
valve is leaking, blood backflow, extra wide P wave
What does the QRS complex represent
ventricular contraction
What does the T wave represent?
ventricular relaxation
The tricuspid valve is closed ________. --when the ventricle is in systole -- while the atrium is contracting -- while the ventricle is in diastole -- by the movement of blood from atrium to ventricle
when the ventricle is in systole
How does the Parasympathetic nervous system affect the Heart rate?
ACH opens ligand gated K+ channels longer to reach threshold slowed heart rate
As pressure in the aorta rises, more ventricular pressure is required to open the aortic valve.
TRUE
Bradychardia
<60 beats/min longer R-R
Tachycardia
>100 beats/min short T-P interval
which is true about cardiac output --If a semilunar valve were partially obstructed, the end systolic volume in the affected ventricle would be decreased. --Stroke volume increases if end diastolic volume decreases. --Decreased venous return will result in increased end diastolic volume. -- A slow heart rate increases end diastolic volume, stroke volume, and force of contraction.
A slow heart rate increases end diastolic volume, stroke volume, and force of contraction.
Is the Pulmonary trunk an artery or a vein?
ARTERY
Damage to the ________ is referred to as heart block.
AV Node
Which of the following is not part of the conduction system of the heart? AV valve AV node bundle of His SA node
AV Valve
when the semilunar valves are opened which of the following are occuring? coronary arteries fill AV valves are closed Ventricles are in systole Ventricles are in diastole Blood enters aorta Blood enters pulmonary arteries atria contract
AV valves are closed Ventricles are in Diastole Blood enters aorta
What does the P wave represent?
Atrial contraction
Why does the coronary sinus drain blood to the right atrium and not the left?
Because it is still apart of the systemic system.
During the period of ventricular filling ________. the P wave on the ECG has the peak the atria remain in diastole pressure in the heart is at its peak blood flows passively through the atria and the open AV valves into the ventricles
Blood passively flows through the atria and the open AV valves into the ventricles.
Norepinephrine acts on the heart by ________.
Causing the threshold to be reached more quickly
Normal heart sounds are caused by which of the following events?
Closing of the heart Valves
The coronary sinus drains blood to the Left or Right atrium
Right atrium
Autonomic regulation of heart valve is via two reflex centers found in the pons.
FALSE
Cardiac muscle has more mitochondria and depends less on a continual supply of oxygen than does skeletal muscle.
FALSE
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
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
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.
What major ion channel is responsible for the depolarization phase of the action potential of the conducting cells?
FAST voltage gated Ca++ channels
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
which of the following has the thickest wall
Left ventricle
which vessle is in contact with myocardium
Loos areolar connective tissue
The time of day most hazardous for heart attacks is ________.
Morning
How does the Sypmathetic nervous system affect the heart rate?
NE opens more ligand gated Na+ channels faster to reach threshold heart rate inclease
Ventricular fibrillation
No QRS missing rythym or pattern
if the papillary muscles fail to contract The ventricles will not pump blood the atria will not pump blood the semilunar valves will not open the AV valves will not open None of these
None of these
Which vessel of the heart receives blood during right ventricular systole?
Pulmonary Trunk
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 sends blood through a smaller valve expands the thoracic cage
Pumps Blood against a greater resistance
AV node is located on
Right atrium
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 is correct? --The tricuspid valve divides the left atrium from the left ventricle. -- The AV valves are supported by chordae tendineae so that regurgitation of blood into the atria during ventricular contraction does not occur. -- Aortic and pulmonary valves control the flow of blood into the heart. -- The mitral valve separates the right atrium from the right ventricle.
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 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. --The refractory period in skeletal muscle is much longer than that in cardiac muscle. -- Each cardiac muscle cell is innervated by a sympathetic nerve ending so that the nervous system can increase heart rate.
The atria, followed by the ventricles, contract as a unit or they do not contract at all.
which is correct? --Connective tissue in the heart wall aids in the conduction of the action potential. --The heart chambers are lined by the endomysium. --The myocardium is the layer of the heart that actually contracts. --The fibrous skeleton forms the bulk of the heart.
The myocardium is the layer of the heart that actually contracts.
what is congestive heart failure?
The pumping efficiency of the heart is depressed so that there is inadequate delivery of blood to body tissues.
Which of the following is longer? The refractory period of cardiac muscle or the refractory period of skeletal muscle?
The refractory period of cardiac muscle
Tissues damaged by myocardial infarction are replaced by connective tissue.
True
Where are arteries connected to?
Ventricles
Which of the events below does not occur when the semilunar valves are open? -Ventricles are in diastole. - Ventricles are in systole. -Blood enters pulmonary arteries and the aorta. - AV valves are closed.
Ventricles are in Diastole
The major ion channel which is responsible for the plateau phase of the contractile cell action potential is
Voltage gated SLOW Ca++ Channels
When is blood pumped into the coronary arteries?
When the aortic Semilunar valve is closed and the ventricle is in diastole
Hemorrhage with a large loss of blood causes ________.
a lowering of blood pressure due to change in cardiac output
Papillary muscles function to
adjust tension of the chordae tendinae
Which of these vessels receives blood during ventricular systole? aorta only both the aorta and pulmonary trunk pulmonary arteries only pulmonary veins only
both the aorta and pulmonary trunk
What is tachycardia
bursts of atrial contractions with little pause between them.
If cardiac muscle is deprived of its normal blood supply, damage would primarily result from ________.
decreased delivery of oxygen
Cardiac muscle has more mitochondria and depends less on a continual supply of oxygen than does skeletal muscle
false
Blood within the pulmonary veins returns to the ________.
left atrium
Which heart chamber receives blood from the pulmonary veins?
left atrium
Which chamber pumps oxygenated blood out the aorta to the systemic circuit?
left ventricle
Atrial Fibrillation
no P wave Decreased pumping effectiveness
When viewing a dissected heart, it is easy to visually discern the right and left ventricles by ________.
noticing the thickness of the ventricle walls
Does the pulmonary truck carry oxygen rich or oxygen poor blood?
oxygen poor
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 --contractions would last as long as the refractory period -- it would be much longer before cardiac cells could respond to a second stimulation -- it would be less than 1-2 ms
tetanic contractions might occur, which would stop the heart's pumping action
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 would stop, since the vagal nerves trigger the heart to contract parasympathetic stimulation would increase, causing a decrease in heart rate the heart rate would increase by about 25 beats per minute
the heart rate would increase by about 25 beats per minute
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 tetanic contraction would occur due to the short absolute refractory period of cardiac muscle threshold is reached more quickly and heart rate would increase potassium channels compensate and no change in heart rate would occur
threshold is reached more quickly and heart rate would increase
As pressure in the aorta rises due to atherosclerosis, more ventricular pressure is required to open the aortic valve.
true
