anatomy chapter 18 Flashcards

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1) Normal heart sounds are caused by which of the following events?

A) excitation of the SA node
B) closure of the heart valves
C) friction of blood against the chamber walls
D) opening and closing of the heart valves

Answer: B


2) Which of the events below does not occur when the semilunar valves are open?

A) Ventricles are in diastole.
B) Blood enters pulmonary arteries and the aorta.
C) AV valves are closed.
D) Ventricles are in systole.

Answer: A


3) Hemorrhage with a large loss of blood causes ________.

A) a lowering of blood pressure due to change in cardiac output
B) a rise in blood pressure due to change in cardiac output
C) no change in blood pressure but a slower heart rate
D) no change in blood pressure but a change in respiration

Answer: A


4) The left ventricular wall of the heart is thicker than the right wall in order to ________.

A) accommodate a greater volume of blood
B) expand the thoracic cage during diastole
C) pump blood with greater pressure
D) pump blood through a smaller valve

Answer: C


5) Damage to the ________ is referred to as heart block.

A) SA node
B) AV valves
C) AV bundle
D) AV node

Answer: D


6) The P wave of a normal electrocardiogram indicates ________.

A) ventricular repolarization
B) ventricular depolarization
C) atrial repolarization
D) atrial depolarization

Answer: D


7) Blood within the pulmonary veins returns to the ________.

A) right atrium
B) left atrium
C) right ventricle
D) left ventricle

Answer: B


8) Small muscle masses attached to the chordae tendineae are the ________.

A) trabeculae carneae
B) pectinate muscles
C) papillary muscles
D) venae cavae

Answer: C


9) The term for pain associated with deficient blood delivery to the heart that may be caused by the transient spasm of coronary arteries is ________.

A) ischemia
B) pericarditis
C) myocardial infarct
D) angina pectoris

Answer: D


10) To auscultate the aortic semilunar valve, you would place your stethoscope in the ________.

A) second intercostal space to the right of the sternum
B) second intercostal space to the left of the sternum
C) fifth intercostal space inferior to the left nipple
D) fifth right intercostal space

Answer: A


11) The source of blood carried to capillaries in the myocardium would be the ________.

A) coronary sinus
B) fossa ovalis
C) coronary arteries
D) coronary veins

Answer: C


12) The fact that the left ventricle of the heart is thicker than the right ventricle reveals that it ________.

A) pumps a greater volume of blood
B) pumps blood against a greater resistance
C) expands the thoracic cage
D) sends blood through a smaller valve

Answer: B


13) Which of the following factors does not influence heart rate?

A) skin color
B) age
C) gender
D) body temperature

Answer: A


14) Which of the following is not an age-related change affecting the heart?

A) atherosclerosis
B) decline in cardiac reserve
C) fibrosis of cardiac muscle
D) thinning of the valve flaps

Answer: D


15) If cardiac muscle is deprived of its normal blood supply, damage would primarily result from ________.

A) decreased delivery of oxygen
B) a decrease in the number of available mitochondria for energy production
C) a lack of nutrients to feed into metabolic pathways
D) an inadequate supply of lactic acid

Answer: A


16) If the length of the absolute refractory period in cardiac muscle cells was the same as it is for skeletal muscle cells ________.

A) it would be much longer before cardiac cells could respond to a second stimulation
B) contractions would last as long as the refractory period
C) tetanic contractions might occur, which would stop the heart's pumping action
D) it would be less than 12 ms

Answer: C


17) Norepinephrine acts on the heart by ________.

A) decreasing heart contractility
B) causing a decrease in stroke volume
C) blocking the action of calcium
D) causing threshold to be reached more quickly

Answer: D


18) If the vagal nerves to the heart were cut, the result would be that ________.

A) the heart would stop, since the vagal nerves trigger the heart to contract
B) the heart rate would increase by about 25 beats per minute
C) the AV node would become the pacemaker of the heart
D) parasympathetic stimulation would increase, causing a decrease in heart rate

Answer: B


19) Foramen ovale ________.

A) connects the two atria in the fetal heart
B) is a condition in which the heart valves do not completely close
C) is a shallow depression in the interventricular septum
D) is a connection between the pulmonary trunk and the aorta in the fetus

Answer: A


20) Which vessel of the heart receives blood during right ventricular systole?

A) venae cavae
B) pulmonary trunk
C) aorta
D) pulmonary veins

Answer: B


21) Which of these vessels receives blood during ventricular systole?

A) aorta only
B) pulmonary arteries only
C) pulmonary veins only
D) both the aorta and pulmonary trunk

Answer: D


22) Which of the following is not part of the conduction system of the heart?

A) AV node
B) bundle of His
C) AV valve
D) SA node

Answer: C


23) The tricuspid valve is closed ________.

A) while the ventricle is in diastole
B) when the ventricle is in systole
C) while the atrium is contracting
D) by the movement of blood from atrium to ventricle

Answer: B


24) When viewing a dissected heart, it is easy to visually discern the right and left ventricles by ________.

A) tracing out where the auricles connect
B) noticing the thickness of the ventricle walls
C) locating the apex
D) finding the papillary muscles

Answer: B


25) Select the correct statement about the heart valves.

A) The mitral valve separates the right atrium from the right ventricle.
B) The tricuspid valve divides the left atrium from the left ventricle.
C) Aortic and pulmonary valves control the flow of blood into the heart.
D) The AV valves are supported by chordae tendineae so that regurgitation of blood into the atria during ventricular contraction does not occur.

Answer: D


26) Select the correct statement about the function of myocardial cells.

A) The entire heart contracts as a unit or it does not contract at all.
B) Each cardiac muscle cell is innervated by a sympathetic nerve ending so that the nervous system can increase heart rate.
C) The refractory period in skeletal muscle is much longer than that in cardiac muscle.
D) The influx of potassium ions from extracellular sources is the initiating event in cardiac muscle contraction.

Answer: A


27) Select the correct statement about the structure of the heart wall.

A) The fibrous skeleton forms the bulk of the heart.
B) Connective tissue in the heart wall aids in the conduction of the action potential.
C) The heart chambers are lined by the endomysium.
D) The myocardium is the layer of the heart that actually contracts

Answer: D


28) Compared to skeletal muscle, cardiac muscle ________.

A) has gap junctions that allow it to act as a functional syncytium
B) lacks striations
C) has more nuclei per cell
D) cells are larger than skeletal muscle cells

Answer: A


29) During the period of ventricular filling ________.

A) pressure in the heart is at its peak
B) blood flows passively through the atria and the open AV valves into the ventricles
C) the atria remain in diastole
D) it is represented by the P wave on the ECG

Answer: B


30) The second heart sound is heard during which phase of the cardiac cycle?

A) isovolumetric relaxation
B) isovolumetric contraction
C) ventricular ejection
D) ventricular filling

Answer: A


31) The time of day most hazardous for heart attacks is ________.

A) morning
B) noontime
C) evening
D) during sleep

Answer: A


32) If we were able to artificially alter the membrane permeability of pacemaker cells so that sodium influx is more rapid, ________.

A) threshold is reached more quickly and heart rate would increase
B) potassium channels compensate and no change in heart rate would occur
C) heart rate would decrease, but blood pressure would rise due to the excess sodium present
D) tetanic contraction would occur due to the short absolute refractory period of cardiac muscle

Answer: A


33) Select the correct statement about cardiac output.

A) A slow heart rate increases end diastolic volume, stroke volume, and force of contraction.
B) Decreased venous return will result in increased end diastolic volume.
C) If a semilunar valve were partially obstructed, the end systolic volume in the affected ventricle would be decreased.
D) Stroke volume increases if end diastolic volume decreases.

Answer: A


34) During contraction of heart muscle cells ________.

A) the action potential is initiated by voltage-gated slow calcium channels
B) some calcium enters the cell from the extracellular space and triggers the release of larger amounts of calcium from intracellular stores
C) the action potential is prevented from spreading from cell to cell by gap junctions
D) calcium is prevented from entering cardiac fibers that have been stimulated

Answer: B


35) Isovolumetric contraction ________.

A) refers to the short period during ventricular systole when the ventricles are completely closed chambers
B) occurs while the AV valves are open
C) occurs immediately after the aortic and pulmonary valves close
D) occurs only in people with heart valve defects

Answer: A


36) Commotio cordis is heart failure due to a ________.

A) mild electrical shock to the heart itself
B) severe electrical shock to the body
C) relatively mild blow to the chest that occurs during a vulnerable interval (2 ms) when the heart is repolarizing
D) loss of blood from an artery

Answer: C


The myocardium receives its blood supply from the coronary arteries.

Answer: TRUE


Cardiac muscle has more mitochondria and depends less on a continual supply of oxygen than
does skeletal muscle.

Answer: FALSE


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

Answer: 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.

Answer: TRUE


Tissues damaged by myocardial infarction are replaced by connective tissue.

Answer: TRUE


The left side of the heart pumps the same volume of blood as the right.

Answer: TRUE


Chronic release of excess thyroxine can cause a sustained increase in heart rate and a
weakened heart.

Answer: TRUE


Arterial blood supply to heart muscle is continuous whether the heart is in systole or diastole.

Answer: FALSE


Trabeculae carneae are found in the ventricles and never the atria.

Answer: 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.

Answer: FALSE


Autonomic regulation of heart rate is via two reflex centers found in the pons.

Answer: 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.

Answer: FALSE


An ECG provides direct information about valve function.

Answer: FALSE


As pressure in the aorta rises due to atherosclerosis, more ventricular pressure is required to
open the aortic valve.

Answer: TRUE


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

Answer: TRUE