BIO 251 Exam 3 New Latest Version 2025 Best
Studying Material with All Questions, Exams of
Biology GRADED A
Cardiac output is determined by what two variables?
A) stroke volume and ejection fraction
B) heart rate and ejection fraction
C) end-diastolic volume and end-systolic volume
D) heart rate and stroke volume
E) preload and afterload - ANSWER>>D
Regulation of the heart (or any organ or tissue) by neural input, circulating hormones, or any other factor
originating from outside the organ is referred to as ________ control.
A) intrinsic
B) neurogenic
C) extrinsic
D) voluntary
E) myogenic - ANSWER>>C
Which of the following structures is poorly innervated by the parasympathetic nervous system and,
therefore, an increase in parasympathetic activity has little effect on this structure?
A) ventricles
B) conduction pathway
C) sinoatrial node
D) Purkinje fibers
E) atrioventricular node - ANSWER>>A
The SA node is innervated by the
A) sympathetic nervous system only.
B) somatic nervous system only.
C) parasympathetic nervous system only.
D) sympathetic and parasympathetic nervous systems.
E) sympathetic, parasympathetic, and somatic nervous systems. - ANSWER>>D
Which of the following is an effect of parasympathetic activity to the heart?
A) The rate of spontaneous depolarization in SA nodal cells decreases.
B) SA nodal cells are depolarized.
C) Heart rate is increased.
D) cAMP is activated.
E) Postganglionic neurons release acetylcholine, which binds to nicotinic cholinergic receptors in
the SA node. - ANSWER>>A
Which of the following is a FALSE statement about sympathetic activity to the SA node?
A) Norepinephrine binds to beta1 adrenergic receptors.
B) Potassium channel closing is enhanced.
C) cAMP levels in the pacemaker cells increases.
, D) Funny channel opening is enhanced.
E) The rate of spontaneous depolarization is increased. - ANSWER>>B
Under resting conditions, heart rate is primarily under the control of what control system?
A) the parasympathetic nervous system
B) the somatic nervous system
C) the sympathetic nervous system
D) intrinsic mechanisms
E) epinephrine - ANSWER>>A
An increase in heart rate can be mediated through which of the following?
A) a decrease in parasympathetic nervous activity only
B) a decrease in sympathetic activity only
C) an increase in sympathetic activity only
D) an increase in parasympathetic activity and a decrease in sympathetic activity
E) a decrease in parasympathetic activity and an increase in sympathetic activity - ANSWER>>E
Which of the following would NOT result from an increase in ventricular contractility?
A) increased ejection fraction
B) increased stroke volume
C) decreased end-diastolic volume
D) decreased end-systolic volume
E) increased proportion of end-diastolic volume that is ejected - ANSWER>>C
Which of the following best describes the effect of sympathetic activity on ventricular contractile cells?
A) The rates of contraction and relaxation both decrease, whereas the force of contraction increases.
B) The rates of contraction and relaxation both increase, whereas the force of contraction decreases.
C) The rate of contraction and the force of contraction both increase, whereas the rate of relaxation
decreases.
D) The rates of contraction and relaxation and the force of contraction all increase.
E) The force of contraction increases, whereas the rates of contraction and relaxation are not
affected. - ANSWER>>D
Which of the following describes the effect of end- diastolic volume on stroke volume?
A) An increase in end-diastolic volume stretches ventricular muscle cells to lengths greater than optimum,
decreasing the strength of contraction and thereby decreasing stroke volume.
B) An increase in end-diastolic volume stretches ventricular muscle cells to lengths closer to optimum,
increasing the strength of contraction and thereby increasing stroke volume.
C) A decrease in end- diastolic volume creates a vacuum drawing more blood into the ventricle increasing
stroke volume.
D) A decrease in end- diastolic volume allows ventricular muscle cells to relax more during diastole,
allowing more blood to return to the heart increasing stroke volume.
E) A decrease in end- diastolic volume allows cardiac muscle to relax, conserving energy for the next
contraction, thereby increasing stroke volume of that next contraction. - ANSWER>>B
Which of the following variables is N OT an intrinsic factor that alters cardiac function?
A) end-systolic volume
B) hormonal stimulation
C) atrial pressure
Studying Material with All Questions, Exams of
Biology GRADED A
Cardiac output is determined by what two variables?
A) stroke volume and ejection fraction
B) heart rate and ejection fraction
C) end-diastolic volume and end-systolic volume
D) heart rate and stroke volume
E) preload and afterload - ANSWER>>D
Regulation of the heart (or any organ or tissue) by neural input, circulating hormones, or any other factor
originating from outside the organ is referred to as ________ control.
A) intrinsic
B) neurogenic
C) extrinsic
D) voluntary
E) myogenic - ANSWER>>C
Which of the following structures is poorly innervated by the parasympathetic nervous system and,
therefore, an increase in parasympathetic activity has little effect on this structure?
A) ventricles
B) conduction pathway
C) sinoatrial node
D) Purkinje fibers
E) atrioventricular node - ANSWER>>A
The SA node is innervated by the
A) sympathetic nervous system only.
B) somatic nervous system only.
C) parasympathetic nervous system only.
D) sympathetic and parasympathetic nervous systems.
E) sympathetic, parasympathetic, and somatic nervous systems. - ANSWER>>D
Which of the following is an effect of parasympathetic activity to the heart?
A) The rate of spontaneous depolarization in SA nodal cells decreases.
B) SA nodal cells are depolarized.
C) Heart rate is increased.
D) cAMP is activated.
E) Postganglionic neurons release acetylcholine, which binds to nicotinic cholinergic receptors in
the SA node. - ANSWER>>A
Which of the following is a FALSE statement about sympathetic activity to the SA node?
A) Norepinephrine binds to beta1 adrenergic receptors.
B) Potassium channel closing is enhanced.
C) cAMP levels in the pacemaker cells increases.
, D) Funny channel opening is enhanced.
E) The rate of spontaneous depolarization is increased. - ANSWER>>B
Under resting conditions, heart rate is primarily under the control of what control system?
A) the parasympathetic nervous system
B) the somatic nervous system
C) the sympathetic nervous system
D) intrinsic mechanisms
E) epinephrine - ANSWER>>A
An increase in heart rate can be mediated through which of the following?
A) a decrease in parasympathetic nervous activity only
B) a decrease in sympathetic activity only
C) an increase in sympathetic activity only
D) an increase in parasympathetic activity and a decrease in sympathetic activity
E) a decrease in parasympathetic activity and an increase in sympathetic activity - ANSWER>>E
Which of the following would NOT result from an increase in ventricular contractility?
A) increased ejection fraction
B) increased stroke volume
C) decreased end-diastolic volume
D) decreased end-systolic volume
E) increased proportion of end-diastolic volume that is ejected - ANSWER>>C
Which of the following best describes the effect of sympathetic activity on ventricular contractile cells?
A) The rates of contraction and relaxation both decrease, whereas the force of contraction increases.
B) The rates of contraction and relaxation both increase, whereas the force of contraction decreases.
C) The rate of contraction and the force of contraction both increase, whereas the rate of relaxation
decreases.
D) The rates of contraction and relaxation and the force of contraction all increase.
E) The force of contraction increases, whereas the rates of contraction and relaxation are not
affected. - ANSWER>>D
Which of the following describes the effect of end- diastolic volume on stroke volume?
A) An increase in end-diastolic volume stretches ventricular muscle cells to lengths greater than optimum,
decreasing the strength of contraction and thereby decreasing stroke volume.
B) An increase in end-diastolic volume stretches ventricular muscle cells to lengths closer to optimum,
increasing the strength of contraction and thereby increasing stroke volume.
C) A decrease in end- diastolic volume creates a vacuum drawing more blood into the ventricle increasing
stroke volume.
D) A decrease in end- diastolic volume allows ventricular muscle cells to relax more during diastole,
allowing more blood to return to the heart increasing stroke volume.
E) A decrease in end- diastolic volume allows cardiac muscle to relax, conserving energy for the next
contraction, thereby increasing stroke volume of that next contraction. - ANSWER>>B
Which of the following variables is N OT an intrinsic factor that alters cardiac function?
A) end-systolic volume
B) hormonal stimulation
C) atrial pressure
