Human Anatomy & Physiology (2nd Edition)
2nd Edition
ISBN: 9780134553511
Author: Erin C. Amerman
Publisher: PEARSON
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Chapter 17, Problem 4AYKB
Summary Introduction
To review:
The outcome of a toxin that results in creating the same length of the refractory period in cardiac muscles as present in the skeletal muscles.
Introduction:
The heart muscles generate an action potential due to the depolarization of the sinoatrial node (SA node) of the heart, which acts as a natural pacemaker. The action potential leads to muscular contraction, which helps the heart to supply blood to the whole body. The other cells that have the capability to generate an action potential as a result of the depolarization are the skeletal muscle cells and the neuron cells. After one action potential is generated, the cell becomes resistant to generating another action potential for a few seconds. This period is termed as the refractory period.
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Students have asked these similar questions
Which statement about activation of heart muscle cells is TRUE?
A
when a person is resting only a few small motor units in each ventricle are activated in each heartbeat
B
all of the muscle cells in the ventricles depolarize and contract together because they are connected by gap junctions
C
motor neurons must synapse with all of the muscle cells in the ventricles at the same time or fibrillation will occur
D
all of the heart muscle cells have unstable resting membrane potenitals and slowly depolarize to threshold at the same rate
How is long refractory period beneficial for cardiac muscles?
The role of the bundle of his, bundle branches, and purkinje fibers is to
Help conduct the electrical pulse (action potential) to the top of the heart first before
allowing the contraction to spread to the atria.
Help conduct the electrical pulse (action potential) to the whole ventricle.
Help conduct the electrical pulse (action potential) to the bottom of the heart first to
allow it to spread from the bottom to the top of the heart.
To allow the electrical pulse (action potential) to pause for 0.1s before spreading to the
ventricle.
Chapter 17 Solutions
Human Anatomy & Physiology (2nd Edition)
Ch. 17.1 - Where is the heart located, and how large is it?Ch. 17.1 - What are the hearts upper and lower chambers...Ch. 17.1 - What are the sources from which blood flows into...Ch. 17.1 - 4. Which side of the heart is considered the...Ch. 17.1 - Which side of the heart is considered the systemic...Ch. 17.2 - Prob. 1QCCh. 17.2 - Prob. 2QCCh. 17.2 - 3. What are the three layers of the heart wall,...Ch. 17.2 - 4. What are the four main great vessels? From...Ch. 17.2 - How do the right and left ventricles differ in...
Ch. 17.2 - 6. Why do you think it is important to ensure via...Ch. 17.2 - 7. What is the overall pathway of blood flow...Ch. 17.2 - Prob. 8QCCh. 17.2 - Prob. 9QCCh. 17.2 - Prob. 10QCCh. 17.3 - How do pacemaker and contractile cells differ?...Ch. 17.3 - 2. What are intercalated discs? What is their...Ch. 17.3 - Prob. 3QCCh. 17.3 - Prob. 4QCCh. 17.3 - What is the sequence of events of a contractile...Ch. 17.3 - How does the refractory period of cardiac muscle...Ch. 17.3 - 7. What does an ECG record?
Ch. 17.3 - What are the five waves in an ECG, and what do...Ch. 17.4 - What causes the heart sounds S1 and S2?Ch. 17.4 - Prob. 2QCCh. 17.4 - Prob. 3QCCh. 17.4 - Is the end-diastolic or the end-systolic volume of...Ch. 17.4 - 5. Walk through the mechanical events of the...Ch. 17.4 - 6. Relate the ECG waves to the cardiac cycle...Ch. 17.4 - 7. How does the left ventricular pressure...Ch. 17.5 - Prob. 1QCCh. 17.5 - What is cardiac output? How does it relate to...Ch. 17.5 - Prob. 3QCCh. 17.5 - What is the Frank-Starling law, and how does it...Ch. 17.5 - What is a chronotropic agent?Ch. 17.5 - Prob. 6QCCh. 17.5 - 7. What effects does the parasympathetic nervous...Ch. 17.5 - How would a hormone that decreases the amount of...Ch. 17.5 - How is heart failure defined?Ch. 17 - 1. Mark the following statements as true or false....Ch. 17 - 2. The pericardial cavity is located between:
a....Ch. 17 - 3. Which of the following statements is true?
a....Ch. 17 - Match the following terms with the correct...Ch. 17 - Fill in the blanks: The coronary arteries are the...Ch. 17 - 6. How do pacemaker cardiac muscle cells differ...Ch. 17 - 7. Cardiac muscle cells are joined by structures...Ch. 17 - Prob. 8CYRCh. 17 - Prob. 9CYRCh. 17 - 10. The _________is the primary pacemaker of the...Ch. 17 - The AV node delay: a. allows the atria and...Ch. 17 - Explain what each of the following terms...Ch. 17 - 13. Mark the following statements as true or...Ch. 17 - Prob. 14CYRCh. 17 - 15. Fill in the blanks: The first heart sound is...Ch. 17 - Cardiac output is equal to: a. end-diastolic...Ch. 17 - Prob. 17CYRCh. 17 - 18. Which of the following statements is false?
a....Ch. 17 - 1. A birth defect called transposition of great...Ch. 17 - 2. Predict which would be more damaging to...Ch. 17 - 3. When the SA node doesn’t function properly, the...Ch. 17 - Prob. 4CYUCh. 17 - Prob. 1AYKACh. 17 - Prob. 2AYKACh. 17 - Prob. 3AYKACh. 17 - Prob. 4AYKB
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