The sinoatrial node sets the pace for the heart as a whole because sinoatrial node cells _____.   A are the only heart cells with an unstable resting membrane potential.   B are the only heart cells capable of initiating an action potential without the influx of positive ions through gap junction   C are located at the top of the heart in the interatrial septum   D have a faster rate of spontaneous depolarization than other pacemaker cells

Q: The pacemaker cardiac muscle cells rely on ______________ for their action potentials. a. Na+ leak…

A: The pacemaker cells create rhythmic impulses which set the pace for pumping the blood. The pacemaker…

Q: In a normal heartbeat the ventricles begin to contract ______.   A at exactly the same time as the…

A: The blood circulating through the circulatory system is responsible for the transport of oxygen and…

Q: Reductions in heart rate are normally caused by _____.   A sympathetic stimulation of the…

A: Heart rate is controlled by the two branches of the autonomic (involuntary) nervous system. The…

Q: Nodal (conductile) cells in the heart differ from other myocardiocytes (contractile cells) in that…

A: There are two major types of cardiac muscle cells present: myocardial contractile cells and…

Q: In pacemaker cells the movement of __________ into the cell through voltage-gated channels is…

A: The opening of channels that let positive ions flow into the cell can cause depolarization. Flow of…

Q: Which statement about activation of heart muscle cells is TRUE?   A when a person is resting only a…

A: The electrical conduction system of the heart transmits signals generated usually by the sinoatrial…

Q: If leaky Na+ channels in the cells of the SA Node became more leaky (allowed Na+ through at a faster…

A: Generation of the action potential is a significant characteristic of the cells of the sinoatrial…

Q: Which of these conditions occurs in the repolarization phase of an action potential in pacemaker…

A: When the change in the membrane potential occurs due to voltage decrease, then it is called…

Q: At the time point indicated on the ECG ____.   A blood would be flowing from the ventricles into…

A: An electrocardiogram can be defined as the type of test in which the heart's electrical activity is…

Q: the difference between the action potential of a cardiac contractile cell and an action potential in…

A: Cardiac action potentials in the heart differ considerably from action potentials found in neural…

Q: The atrioventricular valves open because ______.   A relaxation of the ventricles causes the…

A: Atrioventricular valves These are the valves which connect the atrium to the ventricles. There are…

Q: Which of the following channels are involved in the action potential in contractile cells of the…

A: An action potential is a sudden, fast, transitory, and propagating shift in the resting membrane…

Q: Which of the following is true about the pacemaker potential in the heart? a. Decreased K+ efflux…

A: The pacemaker potential, also known as the prepotential, is the slow, positive increase in voltage…

Q: During diastole the blood pressure in the left ventricle is _______.   A lower than the pressure in…

A: The heart is a highly muscularized, involuntary organ of the body. It has four chambers consisting…

Q: Action potentials in the ventricular cardiomyocytes differ from those in the SA node in that action…

A: Heart is the organ that pumps blood to all regions of the body. Muscles of the heart (cardiac…

Q: Which of the following statements about Ca2+ handling in cardiac contractile cells is FALSE?     a.…

A: In our body, there are 3 types of muscle cells such as Skeletal muscle, Smooth muscle and Cardiac…

Q: Repolarization of ventricular myocardiocytes is caused by ______ the cells through voltage-gated…

A: Repolarisation is caused by the movement of positively charged k+ ions out of the cell. it initially…

Q: The function of the right and left bundle branches is to _____.   A rapidly transmit action…

A: The atrioventricular bundle (bundle of His) is a continuation of the specialized tissue of the AV…

Q: An ectopic pacemaker refers to the condition in which _____.   A the rate at which the SA node…

A: An ectopic pacemaker refers to the condition in which the rate at which the SA node cells undergo…

Q: The normal pacemaker of the heart is the ______.   A sinoatrial node   B left atrium   C…

A: Heart is an important organ that pumps blood. Heart is myogenic in nature meaning it is capable of…

Q: Heart muscle cells ______.   A will not contract unless acetylcholine is released at a…

A: Cardiac muscles are known as Myocardium.Cardiac muscles are different from skeletal muscle because…

Q: All of the following are correct about the isovolumetric contraction, except  ____________.…

A: Isovolumetric contraction is that phase of cardiac contraction in which there is no appreciable…

Q: In a normal heartbeat the atria contract ______.   A at exactly the same time as the ventricles   B…

A: Rhythmic pulsation of the heart as a result of an action potential is known as the heartbeat. The…

Q: An electrocardiogram (ECG) measures the ____.   A difference in electrical potential between two…

A: An electrocardiogram or ECG is a simple non-invasive test conducted on the patient to check his /…

Q: During the refractory period a second action potential______.   A cannot occur because…

A: An action potential is generated when the membrane depolarized from resting potential. Resting…

Q: A likely effect of parasympathetic input to the heart would be to _____.     Open additional…

A: Introduction:- The parasympathetic nervous system originates from the medullary central sites (the…

Q: Blood flow through capillaries in the walls of the left ventricle is ______.   A unnecessary…

A: The blood circulating through the circulatory system is responsible for the transport of oxygen and…

Q: Which of these conditions results the unstable resting membrane potential seen in pacemaker cells?

A: The membrane potential is also termed transmembrane potential or membrane voltage. It is the…

Q: In the myogenic response, ________.a. muscle contraction promotes venous return to theheartb.…

A: Cardiovascular system consists of the heart and blood vessels. Heart is  chambered that consists of…

Q: SA node is the main pacemaker of the heart. Why is the normal heart rate lower than the intrinsic…

A: The SA node if the natural pacemaker of the heart. It consists of a group of cells located in the…

Q: Ventricular cardiomyocytes under sympathetic drive during a bout of exercise...   a. Would…

A: Audiences of primary and clinical scientists are familiar with the idea that the sympathetic nervous…

Q: he opening of what channel will cause the plateau phase of an action potential of ventricular…

A: The plateau phase of the cardiac action potential is phase 2. In this phase the permeability of the…

Q: The amount of force that the ventricles produce in a contraction can be increased through ____.   A…

A: It has three components: blood, heart and the blood vessels. Heart is derived from the mesodermal…

Q: What is the consequence of the prolonged plateau of depolarization in ventricular myocytes?   a-it…

A: the consequence of the prolonged plateau of depolarization in ventricular myocytes.

Q: Repolarization of the ventricles typically _______.   A begins at the end of the T-wave and…

A: Electrocardiograms also called ECGs or EKGs is a simple diagnostic machine that checks the…

Q: f the sinoatrial node stopped generating action potentials the heart would _____.   A stop beating…

A: The heartbeat starts with an impulse generated by the sinoatrial node (SA node) also known as the…