BIOLOGY
12th Edition
ISBN: 9781260169614
Author: Raven
Publisher: RENT MCG
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Textbook Question
Chapter 48, Problem 1A
In vertebrate hearts, atria contract from the top, and ventricles contract from the bottom. How is this accomplished?
a. Depolarization from the SA node proceeds across the atria from the top; depolarization from the AV node is carried to the bottom of the ventricles before it emanates over ventricular tissue.
b. The depolarization from the SA node is initiated from motor neurons coming down from our brain; depolarization from the AV node is initiated from motor neurons coming up from our spinal cord.
c. Gravity carries the depolarization from the SA node down from the top of the heart; contraction of the diaphragm forces depolarization from the AV node from the bottom up.
d. This statement is false; both contract from the bottom.
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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 contraction
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When comparing Ist,
2nd and 3rd degree heart block:
a.
Which has the same contraction rate in the ventricles as in the atria?
b.
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C.
Which has a very slow but regular ventricular beat?
d. In 3rd degree heart block, where is the atrial rate set?
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Complete ventricular filling occurs during what phase of the cardiac cycle?
a. when the atria are in diastole
b. when the ventricles are in diastole
c. when the ventricles are in systole
Chapter 48 Solutions
BIOLOGY
Ch. 48.1 - Prob. 1LOCh. 48.1 - Prob. 2LOCh. 48.2 - Prob. 1LOCh. 48.2 - Prob. 2LOCh. 48.2 - Prob. 3LOCh. 48.3 - Prob. 1LOCh. 48.3 - Prob. 2LOCh. 48.4 - Prob. 1LOCh. 48.4 - Prob. 2LOCh. 48.5 - Prob. 1LO
Ch. 48.5 - Prob. 2LOCh. 48.5 - Prob. 3LOCh. 48.5 - Prob. 4LOCh. 48 - Prob. 1DACh. 48 - Prob. 1IQCh. 48 - Prob. 2IQCh. 48 - An ECG measures a. changes in electrical potential...Ch. 48 - Systole is vitally important to heart function and...Ch. 48 - Which of the following is the correct sequence of...Ch. 48 - Which of the following statements is not true? a....Ch. 48 - Prob. 5UCh. 48 - Prob. 6UCh. 48 - When a sphygmomanometer is used, a. blood pulses...Ch. 48 - Prob. 8UCh. 48 - In vertebrate hearts, atria contract from the top,...Ch. 48 - Prob. 2ACh. 48 - The difference between the amphibian and mammal...Ch. 48 - Prob. 4ACh. 48 - Humans have a number of mechanisms that help to...Ch. 48 - Prob. 2SCh. 48 - Is the evolution of the four-chambered heart...Ch. 48 - Prob. 4S
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Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, biology and related others by exploring similar questions and additional content below.Similar questions
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