Fellah A&P II Chapter 18 Heart

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 – Does depend on oxygen

Anastomoses among coronary arterial branches provide collateral routes for blood delivery to the heart muscle

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

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 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

True

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

True

Proxysmal atrial tachycardia is characterized by bursts of atrial contractions with little pause between them

True

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 ________

morning

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

HR

The ________ membrane covers the heart

Visceral Pericardium OR Epicardium

The ________ valve of the heart has three valves with chordae tendineae

Tricuspid

The ___________ and _____________ valves of the heart have no chordae tendineae attached

Aortic and Pulmonary Semilunar

The inner lining of the heart

endocardium

Heart muscle

myocardium

Serous layer covering the heart muscle

epicardium

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

Ischemia

Death of heart muscle cells

Infarction

A condition of rapid and irregular or out-of-phase contraction of heart muscle cells

Fibrillation

An abnormal pacemaker

Ectopic focus

Total heart relaxation

Quiescent period