ANATOMY & PHYSIOLOGY 4/E PAC 1 SEMESTER
4th Edition
ISBN: 9781265061173
Author: McKinley
Publisher: MCG CUSTOM
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Textbook Question
Chapter 19, Problem 7DYKB
Why is it necessary to stimulate papillary muscles in the ventricle slightly earlier than the rest of the ventricular wall myocardium?
- a. to assure rapid conduction speed of the action potential
- b. to pull on AV valve cusps to prevent backflow
- c. to assure blood will surge toward the semilunar valves
- d. to assure coordinated contraction of the ventricular myocardium
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Why is it necessary to stimulate papillary muscles in the ventricle slightly earlier than the rest of the ventricular wall myocardium?
a. to assure rapid conduction speed of the action potential
b. to pull on AV valve cusps to prevent backflow
c. to assure blood will surge toward the semilunar valves
d. to assure coordinated contraction of the ventricular myocardium
Which of the following statements is true about the SA (sinoatrial) node?
a. The action potential created by the pacemaker cells of the SA node directly stimulates the contractile cells of both the atria and ventricles.
b. The rate of spontaneous depolarization of nodal cells is the fastest in the SA node.
c. Pacemaker cells in the SA node form a pathway between the SA and AV nodes.
d. The pacemaker cells, which establish the heart rate, are located only in the SA node.
Suppose that a pacemaker activity in the AV node overtakes the SA node rhythm.
A. What could be the implicatiosn for the atrial and ventricular contraction-relaxation?
B. Draw the ECG for this situation and explain the differences compared to a normal ECG (if any)
Chapter 19 Solutions
ANATOMY & PHYSIOLOGY 4/E PAC 1 SEMESTER
Ch. 19.1 - Prob. 1WDYLCh. 19.1 - Prob. 2WDYLCh. 19.1 - Prob. 3WDYLCh. 19.1 - Prob. 4WDYLCh. 19.1 - Prob. 5WDYLCh. 19.2 - What is the bony structure that protects both the...Ch. 19.2 - Prob. 7WDYLCh. 19.2 - Prob. 8WDYLCh. 19.3 - Prob. 9WDYLCh. 19.3 - Prob. 10WDYL
Ch. 19.3 - Prob. 11WDYLCh. 19.3 - Prob. 12WDYLCh. 19.3 - Prob. 13WDYLCh. 19.3 - Prob. 14WDYLCh. 19.3 - Prob. 15WDYLCh. 19.3 - Prob. 16WDYLCh. 19.3 - What areas of the heart are deprived of blood when...Ch. 19.3 - Prob. 18WDYLCh. 19.4 - Prob. 19WDYLCh. 19.5 - Prob. 20WDYLCh. 19.5 - Which autonomic division is associated with the...Ch. 19.6 - Prob. 22WDYLCh. 19.6 - What is autorhythmicity? Describe how nodal cells...Ch. 19.6 - What is the path of an action potential through...Ch. 19.6 - What anatomic features slow the conduction rate of...Ch. 19.7 - In which direction does Ca2+ move in response to...Ch. 19.7 - What three electrical events occur at the...Ch. 19.7 - What is the significance of the extended...Ch. 19.7 - What events in the heart are indicated by each of...Ch. 19.8 - Pressure changes that occur during the cardiac...Ch. 19.8 - What is occurring during ventricular ejection?Ch. 19.8 - Prob. 32WDYLCh. 19.8 - Define end-diastolic volume, end-systolic volume,...Ch. 19.9 - What are the two factors that determine cardiac...Ch. 19.9 - What is the cardiac output at rest and during...Ch. 19.9 - Prob. 36WDYLCh. 19.9 - Describe the atrial reflex, which involves...Ch. 19.9 - Prob. 38WDYLCh. 19.9 - Prob. 39WDYLCh. 19.10 - What would be the path of blood flow through the...Ch. 19 - Which of the following is the correct circulatory...Ch. 19 - The pericardial cavity is located between the a....Ch. 19 - How is blood prevented from backflowing from the...Ch. 19 - ____ 4. Venous blood draining from the heart wall...Ch. 19 - _____ 5. Calcium channels in the nodal cells...Ch. 19 - ____6. Action potentials are spread rapidly...Ch. 19 - Why is it necessary to stimulate papillary muscles...Ch. 19 - ____ 8. Preload is a measure of a. stretch of...Ch. 19 - ____ 9. All of the following occur when the...Ch. 19 - ____10. What occurs during the atrial reflex? a....Ch. 19 - Prob. 11DYKBCh. 19 - Compare the structure, location, and function of...Ch. 19 - Prob. 13DYKBCh. 19 - Explain why the walls of the atria are thinner...Ch. 19 - Describe the structure and function of...Ch. 19 - Explain the general location and function of...Ch. 19 - Describe the functional differences in the effects...Ch. 19 - Prob. 18DYKBCh. 19 - List the five events of the cardiac cycle, and...Ch. 19 - Define cardiac output, and explain how it is...Ch. 19 - A young man was doing some vigorous exercise when...Ch. 19 - A young man was doing some vigorous exercise when...Ch. 19 - Prob. 3CALCh. 19 - Prob. 4CALCh. 19 - During surgery, the right vagus nerve was...Ch. 19 - Prob. 1CSLCh. 19 - Prob. 2CSLCh. 19 - Your grandfather was told that his SA node...
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- PREDICT A patients mitral valve (left AV valve) does not close completely at the beginning of ventricular systole. What effect would this have on the cardiac cycle?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_forwardwhich of the following mechanisms contributes most to the deterioration of myocardial perfusion in patients with a progressively dilating left ventricle and a cycle of gradual decompensation. A. decreasing left ventricular radius B. decreasing peripheral vascular resistance C. decreasing vestibular pressure D. increasing left ventricular wall tension E. increasing left ventricular wall thicknessarrow_forward
- All of the following occur when the ventricles contract except a. the AV valves close. b. blood is ejected into the aorta. c. the semilunar valves open. d. blood from the pulmonary trunk enters the atria.arrow_forwardThe following is correct about valvular structures A. The AV valves are the structures that divide the upper atria from the lower ventricles B. The pulmonic vale separates the left ventricle from the system circulation C. The tricuspid valve separates the left atrium from the left ventricle D. The mitral valve separates the right atrium from the right ventricle Choose the correct answerarrow_forwardWhich cell types are associated with spontaneous action potential generation in the absence of an external stimulus from other tissues. A. Sino-Atrial node cells (SA node). B. Atrial cells C. Ventricular cells. D. Endothelial cells. E. A and D.arrow_forward
- What is the consequence of the prolonged plateau of depolarization in ventricular myocytes? a-it causes ventricular myocytes to contract for a longer time, allowing the ventricles time to empty b-it gives additional time for the atria to contract, filling the ventricles more completely c-it causes repolarization to be delayed which slows heart rate d-it allows the ventricles a moment to rest before completing contractionarrow_forwardWhich heart valve(s) is/are open during the Ejection phase of the cardiac cycle? A. Tricuspid B. Aortic semilunar valve C. Bicuspid D. Both B & Carrow_forwardThe period between the filling of the ventricles and the opening of the semilunar valves in the cardiac cycle is called: A. Atrial Systole B. Isovolumetirc ventricular contraction C. Isovolumetric ventricular relaxation D. Passive ventricular fillingarrow_forward
- Why does the right ventricle have a bicuspid valve? a. The low pressure generated by the right ventricle is best suited to bicuspid valve compared with a tricuspid valve b. The high pressure generated by the right ventricle would be better controlled by a bicuspid compared with a tricuspid valve c. Only a short pumping distance to the lungs is required for the bicuspid valve d. The right ventricle does not have a bicuspid valvearrow_forwardAn ECG measures a. changes in electrical potential during the cardiac cycle. b. Ca2+ concentration of the ventricles in diastole. c. the force of contraction of the atria during systole. d. the volume of blood being pumped during the contraction cycle.arrow_forwardMatch the following: ? Prevents backflow into the left ventricle ? Prevents backflow into the right atrium ? Prevents backflow into the left atrium ? Prevents backflow into the right ventricle A. Aortic semilunar valve B. Mitral (bicuspid) valve C. Tricuspid valve D. Pulmonary semilunar valvearrow_forward
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