81) In ventricular reflex, a more powerful contraction results in
A) : 1200309.
81) In ventricular reflex, a more powerful contraction results in
A) decreased stroke volume.
B) increased stroke volume.
C) no change in stroke volume.
D) decreased cardiac output.
E) a slower heart rate.
82) ________ release results in a decrease in the force of cardiac contractions.
A) Norepinephrine
B) Epinephrine
C) Acetylcholine
D) Digitalis
E) Glucagon
83) Which of the following most likely occurs in the condition called hyperkalemia?
A) decreased heart rate
B) increased rate of depolarization at the SA node
C) irregular cardiac contractions
D) fluid collection in the pericardial sac
E) elevated calcium concentrations
84) The amount of blood conveyed to the right atrium is referred to as the ________.
A) cardiac output
B) venous return
C) stroke volume
D) P-R interval
E) Q-T interval
85) The release of norepinephrine at synapses in the myocardium results in ________.
A) a decrease in the force of cardiac contractions
B) inhibition of cardiac muscle cell metabolism
C) an increase in stroke volume
D) a decreased heart rate
E) a decrease in cardiac output
86) According to the Frank-Starling principle, the cardiac output is directly related to (the)
A) size of the ventricle.
B) heart rate.
C) venous return.
D) thickness of the myocardium.
E) total amount of blood in the cardiovascular system.
87) Regarding cardiodynamics, which of the following relationships is correct?
A) HR = CO x SV
B) SV = CO x HR
C) CO = HR/SV
D) SV = HR/CO
E) CO = HR x SV
88) When the heart rate and stroke volume in a normal heart increase together, the cardiac output can increase by ________ percent.
A) 50-70
B) 100-350
C) 150-250
D) 250-500
E) 500-700
89) Which statement regarding autonomic innervation of the heart is accurate?
A) The release of norepinephrine (NE) and epinephrine (E) by the adrenal medulla decreases the force and degree of contraction.
B) Norepinephrine released by sympathetic neurons increases the heart rate.
C) Acetylcholine released by parasympathetic neurons results in increased heart rate.
D) Parasympathetic release of norepinephrine at synapses in the myocardium result in an increase in stroke volume.
E) Acetylcholine released by sympathetic neurons result in an increase in the force of cardiac contractions.
90) If a decline in blood pressure or oxygen concentrations occurs, the cardiac centers then call for a(n) ________.
A) decrease in cardiac output.
B) decrease in sympathetic motor neuron activity.
C) decrease in stroke volume.
D) increase in parasympathetic motor neuron activity.
E) increase in cardiac output.
91) The two heart reflexes directly respond to changes in ________.
A) blood volume
B) hormones released
C) oxygen levels in the blood
D) calcium concentrations
E) the pH of blood
81) In ventricular reflex, a more powerful contraction results in
A) : 1200309
