Physio: Chp. 16 Quiz Questions

The resting membrane potential is ___1_____ for skeletal muscle and ____2____ for contractile myocardium. It is ____3____ for autorhythmic myocardium

1) -70 mV 2) -90 mV 3) -60 mV

The rising phase of the action potential is a result of ___1_____ for skeletal muscle, ___2____ for contractile myocardium, and ____3____ for autorhythmic myocardium.

1) Na+ entry 2) Na+ entry 3) Ca2+ entry

Sympathetic stimulation to the pacemaker cells ___1_____ heart rate by ____2____ ion flow through ____3____ and ___4____ channels.

1) increases 2) increasing 3) funny 4) T-type Ca2+

Match the name of the wave with the correlated event. A. P wave B. QRS complex C. T wave D. PR segment E. ST segment 29) immediately followed by ventricular contraction 30) ventricular repolarization 31) ventricular depolarization 32) atrial depolarization

29) B 30) C 31) B 32) A

Autorhythmic cells A) are the same size as myocardial contractile cells. B) have organized sarcomeres. C) contribute to the force of contraction D) None of the answers are correct.

D) None of the answers are correct.

A typical action potential of a myocardial contractile cell lasts ________ millisecond(s). A) less than 1 B) 1-5 C) 50-100 D) at least 200 E) at least 50

D) at least 200

During the plateau phase of the action potentials of myocardial contractile cells, which ion(s) is/are crossing the membrane? A) both Na+ and Ca2+ B) Cl - only C) Na+ only D) both Ca2+ and K+ E) both Na+ and K+

D) both Ca2+ and K+

Mean arterial pressure =

SP + 2DP/3

Cardiac Output =

SV x HR

The cells responsible for establishing the rate of a cardiac contraction are the _______.

pacemaker cells

An increase in blood vessel diameter is known as ________

vasodilation

The amount of blood returning to the heart is the ________.

venous return

40. Ivabrandine selectively blocks Funny channels in the heart. Which statement would be true concerning a patient who is taking this drug? A) The drug would slow down this individual's heart rate. B) This patient must have been suffering from bradycardia. C) This drug would decrease contractility of the patient's heart. D) This drug would raise the blood pressure of the patient. E) The amount of calcium entering the patient's heart cells would increase.

A) The drug would slow down this individual's heart rate.

The term that describes the volume of blood circulated by the heart in one minute is A) cardiac output (CO). B) heart rate (HR). C) end-diastolic volume (EDV). D) stroke volume (SV). E) end-systolic volume (ESV).

A) cardiac output (CO).

The depolarization of the pacemaker action potential spreads to adjacent cells through A) gap junctions. B) tight junctions. C) chemical synapses. D) desmosomes.

A) gap junctions.

The action potentials of myocardial autorhythmic cells (nodal/pacemaker), are due to a combination of increasing Na2+ ________ and decreasing K+ ________. A) influx, efflux B) efflux, influx C) influx, influx D) efflux, efflux

A) influx, efflux

5. The action potential in a cardiac contractile cell causes A) opening of L-type calcium channels. B) opening of ryanodine receptor calcium channels. C) activation of sodium-potassium ATPase. D) activation of T-type calcium channel. E) opening of F-type sodium channel.

A) opening of L-type calcium channels.

The P wave of an ECG corresponds to A) the depolarization of the atria. B) the progressive wave of ventricular depolarization. C) the repolarization of the ventricles. D) atrial repolarization. E) None of the answers are correct.

A) the depolarization of the atria.

During ventricular ejection, A) the ventricles are in systole. B) the QRS complex is just starting. C) the semilunar valves are closed. D) the AV valves are open. E) blood is forced into veins.

A) the ventricles are in systole.

In which situation would the stroke volume be the greatest? A) when venous return is increased B) when venous return is decreased C) when the force of contraction is decreased

A) when venous return is increased

Using this figure calculate the following values: A. Stroke volume B. Cardiac output if HR is 75bpm C. Mean Arterial Pressure

A. SV=EDV-ESV=135-65= 70mL/beat B. CO=SV X HR= 70 X 75=5250 mL/min C. MAP= SP+ 2DP/ 3= 120+ 2(85)/ 3= 96.7 mmHg

Put these autorhythmic cells into the correct order for conveying electrical signals through a normal heart. 1. bundle of His 2. internodal pathway 3. Purkinje fibers 4. atrioventricular node 5. sinoatrial nodes 6. left and right bundle branches A) 5, 2, 1, 6, 4, 3 B) 5, 2, 4, 1, 6, 3 C) 4, 2, 5, 1, 6, 3 D) 3, 6, 1, 4, 2, 5 E) 5, 4, 1, 6, 2, 3

B) 5, 2, 4, 1, 6, 3

Which of the following events result in the first heart sound? A) The AV valves open. B) The AV valves close. C) The semilunar valves close. D) The semilunar valves open. E) The atria contract.

B) The AV valves close

Drugs known as beta blockers will A) increase heart rate. B) decrease heart rate. C) increase stroke volume. D) increase cardiac output. E) decrease the end-systolic volume.

B) decrease heart rate.

14. The AV node is important because it A) directs electrical impulses from the ventricles to the atria. B) delays the transmission of the electrical impulses to the ventricles in order for the atria to finish contracting. C) serves as the pacemaker in a normal heart. D) electrically opens the AV valves.

B) delays the transmission of the electrical impulses to the ventricles in order for the atria to finish contracting

A certain drug decreases heart rate by producing hyperpolarization in the pacemaker cells of the heart. This drug probably binds to A) nicotinic receptors. B) muscarinic receptors. C) alpha adrenergic receptors. D) beta receptors.

B) muscarinic receptors.

A heart rate of 125 beats per minute could be correctly termed A) bradycardia. B) tachycardia. C) an arrhythmia. D) fibrillation. E) a normal resting heart rate.

B) tachycardia

20. During the isovolumetric phase of ventricular systole, A) the atria contract. B) the atrioventricular valves and semilunar valves are closed. C) blood is ejected into the great vessels. D) the ventricles are relaxing. E) the ventricles are filling with blood.

B) the atrioventricular valves and semilunar valves are closed.

If the membranes of the cardiac muscle cells in the SA node become more permeable to potassium ions, A) the heart rate will increase. B) the heart rate will decrease. C) the membrane will depolarize. D) the stroke volume will increase. E) the intracellular concentration of calcium ion will increase.

B) the heart rate will decrease

The cardiac output is equal to A) the difference between the end-diastolic volume and the end-systolic volume. B) the product of heart rate and stroke volume. C) the difference between the stroke volume at rest and the stroke volume during exercise. D) the stroke volume less the end-systolic volume. E) the product of heart rate and blood pressure.

B) the product of heart rate and stroke volume.

The QRS complex of an ECG corresponds to A) the depolarization of the atria. B) the progressive wave of ventricular depolarization. C) the repolarization of the ventricles. D) atrial repolarization. E) None of the answers are correct.

B) the progressive wave of ventricular depolarization.

If the connection between the AV node and bundle of His becomes blocked, A) the ventricles will beat faster. B) the ventricles will beat more slowly. C) the ventricular rate of contraction will not be affected. D) the stroke volume will increase. E) tachycardia will occur.

B) the ventricles will beat more slowly.

3. Miguel is a 25-year-old jogger. His resting pulse is 70 bpm. His blood volume is approximately 6.8 liters. At rest, his cardiac output is 6.3 liters/min. What must his stroke volume be?

CO= HR X SV SV= CO/HR = 6.3 L/ 70 bpm= 90 mL

Put these phases of the cardiac cycle in the correct order. 1. opening of the semilunar valves 2. isovolumetric ventricular contraction 3. beginning of atrial systole 4. closure of the AV valves 5. completion of ventricular filling 6. beginning of ventricular systole 7. ventricular relaxation 8. ventricular ejection A) 4, 5, 1, 2, 7, 8, 3, 6 B) 3, 2, 6, 1, 4, 5, 8, 7 C) 3, 5, 6, 4, 2, 1, 8, 7 D) 3, 5, 6, 1, 8, 4, 2, 7 E) 3, 2, 6, 4, 5, 8, 7, 1

C) 3, 5, 6, 4, 2, 1, 8, 7

6. The rapid depolarization phase of the action potentials of myocardial contractile cells is due to which ion(s)? A) Ca2+ only B) K+ only C) Na+ only D) both Ca2+ and K+ E) both Na+ and K+

C) Na+ only

Abnormally slow conduction through the ventricles would change the ________ in an ECG tracing. A) P wave B) T wave C) QRS complex D) PR interval E) RT interval

C) QRS complex

If the EDV is 140 mL, which other values are most likely to occur in a healthy, normal person? A) The ESV could be 70 mL and the SV could be 90 mL. B) The ESV could be 90 mL and the SV could be 50 mL. C) The ESV could be 50 mL and the SV could be 90 mL. D) The cardiac output could be 90 mL. E) Diastolic pressure would be equal to EDV.

C) The ESV could be 50 mL and the SV could be 90 mL.

Ventricular contraction A) begins during the first part of the P wave. B) begins just after the T wave. C) begins just after the Q wave. D) begins during the latter part of the P wave. E) None of the answers are correct.

C) begins just after the Q wave.

The term used to describe the amount of blood in the ventricle available to be pumped out of the heart during the next contraction is A) cardiac output (CO). B) heart rate (HR). C) end-diastolic volume (EDV). D) stroke volume (SV). E) end-systolic volume (ESV).

C) end-diastolic volume (EDV).

The volume of blood ejected from each ventricle during a contraction is called the A) end-diastolic volume. B) end-systolic volume. C) stroke volume. D) cardiac output. E) cardiac reserve.

C) stroke volume.

21. During ventricular systole, A) the atria are contracting. B) blood is entering the ventricles. C) the AV valves are closed. D) the pressure in the ventricles declines. E) the ventricles are relaxed.

C) the AV valves are closed.

26. Which of these will increase the heart rate? A) only sympathetic stimulation to the SA node B) only the application of epinephrine to the SA node C) only the application of acetylcholine to the SA node D) both sympathetic stimulation and application of epinephrine to the SA node E) both sympathetic stimulation and application of acetylcholine to the SA node

D) both sympathetic stimulation and application of epinephrine to the SA node

9. The end of the plateau phase is due to the ________ of Ca2+ channels and ________ of K+ channels. A) opening, opening B) closing, closing C) opening, closing D) closing, opening

D) closing, opening

10. The flattening of the action potentials of myocardial contractile cells, called the plateau phase, is due to a combination of ________ K+ permeability and ________ Ca2+ permeability. A) increasing, increasing B) decreasing, decreasing C) increasing, decreasing D) decreasing, increasing

D) decreasing, increasing

Acetylcholine slows the heart rate by A) just increasing ion influx, thus increasing the rate of depolarization. B) just increasing the permeability to Ca2+. C) just increasing the permeability to K+. D) just decreasing the permeability to Ca2+. E) increasing the permeability to K+ and decreasing the permeability to Ca2+.

E) increasing the permeability to K+ and decreasing the permeability to Ca2+.

The ________ is the amount of blood in a ventricle at the beginning of systole

EDV

Stroke Volume =

EDV-ESV

The _______ is the amount of blood in a ventricle after it has contracted and before it begins to refill.

ESV

The period of time from the beginning of one heartbeat to the beginning of the next is termed the ________.

cardiac cycle