Human Physiology: An Integrated Approach (8th Edition)
8th Edition
ISBN: 9780134605197
Author: Dee Unglaub Silverthorn
Publisher: PEARSON
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Textbook Question
Chapter 14.3, Problem 17CC
A new cardiac drug called ivabradine selectively blocks If channels in the heart. What effect would it have on heart rate and for what medical condition might it be used?
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A 65-year old man with heart failure is unable to climb a flight of stairs without experiencing dyspnea. After several years of therapy with carvedilol, captopril and furosemide, the therapeutic plan probably needs to change now. You empirically add digoxin to improve cardiac muscle contractility. Within 4 week he has a marked improvement in his symptoms. Which of the following best describes the main cellular action of digoxin that accounts for its ability to improve his cardiovascular function?
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Chapter 14 Solutions
Human Physiology: An Integrated Approach (8th Edition)
Ch. 14.1 - A cardiovascular system has what three major...Ch. 14.1 - What is the difference between (a) the pulmonary...Ch. 14.2 - Which is more important for determining flow...Ch. 14.2 - The two identical tubes below have the pressures...Ch. 14.2 - All four tubes below have the same driving...Ch. 14.2 - Two canals in Amsterdam are identical in size, but...Ch. 14.3 - What prevents electrical signals from passing...Ch. 14.3 - Prob. 8CCCh. 14.3 - Prob. 9CCCh. 14.3 - Compare the receptors and channels involved in...
Ch. 14.3 - If a myocardial contractile cell is placed in...Ch. 14.3 - A drug that blocks all Ca2+ channels in the...Ch. 14.3 - Which ions moving in what directions cause the...Ch. 14.3 - At the molecular level, what is happening during...Ch. 14.3 - Lidocaine is a molecule that blocks the action of...Ch. 14.3 - What does increasing K+ permeability do to the...Ch. 14.3 - A new cardiac drug called ivabradine selectively...Ch. 14.3 - Do you think that the Ca2+ channels in...Ch. 14.3 - What happens to the action potential of a...Ch. 14.3 - In an experiment, the vagus nerve, which carries...Ch. 14.4 - Name two functions of the AV node. What is the...Ch. 14.4 - Prob. 22CCCh. 14.4 - Occasionally an ectopic pacemaker {ktopos, out of...Ch. 14.4 - Prob. 24CCCh. 14.4 - Which chamberatrium or ventriclehas higher...Ch. 14.4 - Prob. 26CCCh. 14.4 - Prob. 27CCCh. 14.4 - Prob. 28CCCh. 14.4 - Prob. 29CCCh. 14.4 - Why does ventricular pressure shoot up suddenly at...Ch. 14.4 - Prob. 31CCCh. 14.4 - Prob. 32CCCh. 14.4 - A persons aortic valve opening has become...Ch. 14 - What contributions to understanding the...Ch. 14 - List three functions of the cardiovascular system.Ch. 14 - Prob. 3RQCh. 14 - Prob. 4RQCh. 14 - Prob. 5RQCh. 14 - Prob. 6RQCh. 14 - Prob. 7RQCh. 14 - Distinguish between the two members of each of the...Ch. 14 - Prob. 9RQCh. 14 - Prob. 10RQCh. 14 - What is the proper term for each of the following?...Ch. 14 - List the events of the cardiac cycle in sequence,...Ch. 14 - Prob. 13RQCh. 14 - Compare and contrast the structure of a cardiac...Ch. 14 - Prob. 15RQCh. 14 - Correlate the waves of an ECG with mechanical...Ch. 14 - Prob. 17RQCh. 14 - List and briefly explain four types of information...Ch. 14 - Define inotropic effect. Name two drugs that have...Ch. 14 - Prob. 20RQCh. 14 - Police Captain Jeffers has suffered a myocardial...Ch. 14 - Prob. 22RQCh. 14 - Prob. 23RQCh. 14 - Police Captain Jeffers in question 21 has an...Ch. 14 - Prob. 25RQCh. 14 - Prob. 26RQCh. 14 - Prob. 27RQCh. 14 - A person has a total blood volume of 5 L. Of this...
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- In the given table, three of the anatomical and physiological terms are similar or related; one does not belong with the other three. Choose the term that does NOT belong in each of the following groups. A B C D 1 Pulmonary Trunk Vena Cava Right Side of the Heart Left Side of the Heart 2 QRS Wave T Wave P Wave Electrical Activity of the Ventricles 3 AV Valves Closed AV Valves Opened Ventricular Systole Semilunar Valves Open 4 Tricuspid Valve Mitral Valve Bicuspid Valve Left AV Valve 5 Pulmonary Valve Umbilical Artery Pulmonary Vein Superior Vena Cavaarrow_forwardThe pressure in the aorta changes throughout the cardiac cycle. During systole, as the heart contracts, the outflux of blood into the aorta causes an increase in pressure, whereas during diastole the pressure decreases as the heart relaxes. A simple model for the aortic pressure waveform is given by the Windkessel effect described by the image below. In this model, the heart is considered a pressure generating pump which is directly connected to an elastic compartment (the aorta), which in turn is connected to a rigid set of peripheral vessels (the hose of the firefighter). 5 Pump Heart Air Windkessel Elastic arteries In order to find the aortic pressure waveform from the Windkessel model, a mass balance formulation around the aorta must be formulated. Coming into the aorta from the heart we have the flowrate Q(t). According to conservation of mass, this inflow rate Q(t) must be equal to the outflow rate into the peripheral vessels and the change in volume of the aorta. To find these…arrow_forwardApparatuses used in Physiology: 1. Discuss briefly the purpose of each apparatus. a. Kymograph b. Inductorium c. Signal Magnet d. Simple Key e. Heart Lever f. Hand electrodearrow_forward
- You are testing a compound as cardioactive drug. You know the compound is an agonist of acetylcholine (ACh) at the relevant ACh receptor (AChR) on sinoatrial (SA) node cells. Briefly describe how the action of the drug likely would affect the electrical signal produced by the SA node cells. In respect of cardiac output, what would you expect to be the effect of this drug?arrow_forwardSA node is the main pacemaker of the heart. Why is the normal heart rate lower than the intrinsic firing rate of the SA node? A. sympathetic inputs from the hypothalamus are slowing it down B. parasympathetic inputs from medulla oblongata are slowing it down C. there is inertia in heart muscle as it takes time for impulse to spread through all the cells D. centrifugal inputs from the AV node are slowing it downarrow_forwardIf leaky Na+ channels in the cells of the SA Node became more leaky (allowed Na+ through at a faster rate), what would happen to the heart rate? a-it wouldn't change b-it would decrease c-it would increasearrow_forward
- The Greek anatomist Erasistratus, originally from Ceos, identified the correct function of the right atrioventricular valve of the human heart, which was to prevent backward flow of blood from: the right ventricle to the right atrium the right ventricle to the left ventricle the right ventricle to the left atrium the left ventricle to the right ventricle the left ventricle to the left atriumarrow_forwardNitroglycerine is given as a therapy to patients suffering from angina pains. It gets converted into nitric oxide that results in the relaxation of smooth muscles surrounding the blood vessels. What will be the effect of this molecule on the stroke volume of the heart?arrow_forwardWhich of the following statements best describes the differences in the regulation of cardiac and skeletal muscle contraction? The amount of contractile force actively generated by muscle cells is increased by stretch in skeletal muscle and decreased by stretch in cardiac muscle. Cardiac muscle is stimulated by motor neurons and skeletal muscle by neurones from the autonomic nervous system. Skeletal muscle contractile force is augmented by increasing the firing frequency of action potentials whereas cardiac muscle contractile force is enhanced by noradrenaline increasing calcium influx through ion channels. Ryanodine receptors in skeletal muscle are opened by a mechanism that requires calcium influx whereas in cardiac muscle membrane depolarisation alone without calcium influx is sufficient to open ryanodine receptors.arrow_forward
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