Homework Help is Here – Start Your Trial Now!
Science
Biology
Use the ionic current traces to explain the shape and duration of the ventricular AP shown.

Use the ionic current traces to explain the shape and duration of the ventricular AP shown.

Human Anatomy & Physiology (11th Edition)
Human Anatomy & Physiology (11th Edition)
11th Edition
ISBN:9780134580999
Author:Elaine N. Marieb, Katja N. Hoehn
Publisher:Elaine N. Marieb, Katja N. Hoehn
Chapter1: The Human Body: An Orientation
Section: Chapter Questions
Problem 1RQ: The correct sequence of levels forming the structural hierarchy is A. (a) organ, organ system,...
See similar textbooks
icon
Related questions
Question
Use the ionic current traces to explain the shape and duration of the ventricular AP shown.
 
 
 
**Top Image: Action Potential of a Cardiac Muscle Fiber** The graph on the top displays the action potential of a cardiac muscle fiber. The y-axis represents membrane potential (in millivolts, mV), ranging from -90 mV to +20 mV. The x-axis displays time in milliseconds (ms). The curve is marked with numbers 0 through 4, denoting different phases of the cardiac action potential: - **Phase 0 (Depolarization):** A sharp upward spike due to a rapid influx of sodium ions (Na⁺). - **Phase 1 (Initial Repolarization):** A slight dip following the peak as sodium channels inactivate and a transient outward current occurs. - **Phase 2 (Plateau):** A prolonged plateau phase is visible due to the balance between calcium ion (Ca²⁺) influx and potassium ion (K⁺) efflux. - **Phase 3 (Repolarization):** A downward slope indicating the efflux of K⁺, leading to repolarization of the membrane. - **Phase 4 (Resting Potential):** The cell returns to its resting membrane potential, preparing for the next action potential. **Bottom Image: Ion Currents During Action Potential** Three separate graphs illustrate the ionic currents during the cardiac action potential, comparing Na⁺, Ca²⁺, and cumulative K⁺ currents: - **I_Na (Sodium Current):** Shows a rapid inward current at the beginning, correlating with Phase 0 of the action potential. As convention, inward currents are downward. - **I_Ca (Calcium Current):** Depicts a sustained inward current during the plateau phase (Phase 2), contributing to its maintenance. - **I_K (Potassium Current):** Illustrates an outward current with significant activity during Phases 1 and 3, correlating with repolarization. Outward currents are represented upward. Overall, the diagrams collectively explain how the movement of different ions across the cardiac cell membrane create the characteristic shape of the cardiac action potential. This is essential for understanding the electrical activity that regulates heart contractions.
Transcribed Image Text:**Top Image: Action Potential of a Cardiac Muscle Fiber** The graph on the top displays the action potential of a cardiac muscle fiber. The y-axis represents membrane potential (in millivolts, mV), ranging from -90 mV to +20 mV. The x-axis displays time in milliseconds (ms). The curve is marked with numbers 0 through 4, denoting different phases of the cardiac action potential: - **Phase 0 (Depolarization):** A sharp upward spike due to a rapid influx of sodium ions (Na⁺). - **Phase 1 (Initial Repolarization):** A slight dip following the peak as sodium channels inactivate and a transient outward current occurs. - **Phase 2 (Plateau):** A prolonged plateau phase is visible due to the balance between calcium ion (Ca²⁺) influx and potassium ion (K⁺) efflux. - **Phase 3 (Repolarization):** A downward slope indicating the efflux of K⁺, leading to repolarization of the membrane. - **Phase 4 (Resting Potential):** The cell returns to its resting membrane potential, preparing for the next action potential. **Bottom Image: Ion Currents During Action Potential** Three separate graphs illustrate the ionic currents during the cardiac action potential, comparing Na⁺, Ca²⁺, and cumulative K⁺ currents: - **I_Na (Sodium Current):** Shows a rapid inward current at the beginning, correlating with Phase 0 of the action potential. As convention, inward currents are downward. - **I_Ca (Calcium Current):** Depicts a sustained inward current during the plateau phase (Phase 2), contributing to its maintenance. - **I_K (Potassium Current):** Illustrates an outward current with significant activity during Phases 1 and 3, correlating with repolarization. Outward currents are represented upward. Overall, the diagrams collectively explain how the movement of different ions across the cardiac cell membrane create the characteristic shape of the cardiac action potential. This is essential for understanding the electrical activity that regulates heart contractions.
Expert Solution
Step 1
  • The above figure shows the action potential and the below figure indicates the ions movements, influx of ions is shown by downward deflection while efflux of ions shown by upward deflection.
  • Curve will rise if there is influx of positive ions  and curve will show a decrease if there will be ions efflux .
steps

Step by step

Solved in 4 steps

SEE SOLUTIONCheck out a sample Q&A here
Blurred answer
Knowledge Booster
Cardiovascular system
Learn more about
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.
Recommended textbooks for you
Human Anatomy & Physiology (11th Edition)
Human Anatomy & Physiology (11th Edition)
Biology
ISBN:
9780134580999
Author:
Elaine N. Marieb, Katja N. Hoehn
Publisher:
PEARSON
Biology 2e
Biology 2e
Biology
ISBN:
9781947172517
Author:
Matthew Douglas, Jung Choi, Mary Ann Clark
Publisher:
OpenStax
Anatomy & Physiology
Anatomy & Physiology
Biology
ISBN:
9781259398629
Author:
McKinley, Michael P., O'loughlin, Valerie Dean, Bidle, Theresa Stouter
Publisher:
Mcgraw Hill Education,
Molecular Biology of the Cell (Sixth Edition)
Molecular Biology of the Cell (Sixth Edition)
Biology
ISBN:
9780815344322
Author:
Bruce Alberts, Alexander D. Johnson, Julian Lewis, David Morgan, Martin Raff, Keith Roberts, Peter Walter
Publisher:
W. W. Norton & Company
Laboratory Manual For Human Anatomy & Physiology
Laboratory Manual For Human Anatomy & Physiology
Biology
ISBN:
9781260159363
Author:
Martin, Terry R., Prentice-craver, Cynthia
Publisher:
McGraw-Hill Publishing Co.
Inquiry Into Life (16th Edition)
Inquiry Into Life (16th Edition)
Biology
ISBN:
9781260231700
Author:
Sylvia S. Mader, Michael Windelspecht
Publisher:
McGraw Hill Education
SEE MORE TEXTBOOKS