Resting Membrane Potential
• The resting membrane potential of normal cardiac muscle is -85 t0 –95mV and for the specialized areas is –90 to –100mV
What our notes say
- • The resting membrane potential of normal cardiac muscle is -85 t0 –95mV and for the specialized areas is –90 to –100mV (Cardiovascular system examination revised 2012 — Past Paper Questions & Answers)
- With its inactivation gates closed, the channel is said to be inactivated and the membrane potential eventually goes back to the resting membrane potential. (Medical Physiology Assorted SAQs — With Answers (Past Paper Study Guide))
- At resting membrane potential:A) Inside is more negative than outside (Biochemical Endocrinology, MBMB2234: Neurochemistry)
- Resting membrane potential is NOT maintained by:A) Semipermeable membrane (Biochemical Endocrinology, MBMB2234: Neurochemistry)
- Briefly describe the roles of sodium ions and potassium ions in the development and maintenance of the resting membrane potential. (Medical Physiology End of Semester 1 Exam — March 2019 (Past Paper))
Study material on Resting Membrane Potential
- Biochemical Endocrinology, MBMB2234: Neurochemistry
- Medical Physiology Mid-Semester 2 CAT — 2021 (Past Paper)
Practice questions on Resting Membrane Potential
What would happen to the resting membrane potential of a neuron if sodium (Na+) channels were normally open in the membrane, but everything else was the same?
- Nothing much would happen, and it would remain at approximately -65 mV
- It would definitely be less negative than the normal resting potential
- It would definitely be more negative than the normal resting potential
- It would lose its polarization and stand at exactly 0 mV
- None of the above
Answer: B. If sodium channels were normally open, sodium would continuously flow into the cell down its concentration gradient, making the inside less negative (more positive) than the normal resting potential of -65 mV. --- ---
The resting membrane potential of GI smooth muscle is characterized by:
- A steady, flat baseline at -70mV
- Slow wave oscillations (Basic Electrical Rhythm)
- Constant action potential firing
- Absence of any electrical activity
Answer: B. GIT smooth muscle exhibits 'slow waves', which are rhythmic fluctuations in membrane potential that do not always reach threshold.
Complete Marked out of 1.00 The resting membrane potential in a nerve cell Select one:
- Is stable in pace-maker cells
- Is always variable in any one particular nerve cell
- Depends on voltage-gated magnesium channels
- May vary in voltage from cell to cell and depending on cell size
- Is influenced more by the leakage of chloride ions than the leakage of potassium ions
Answer: A.
Complete Marked out of 1.00 What would happen to the resting membrane potential of a neuron if sodium (Na+) channels were normally open in the membrane, but everything else was the same? Select one:
- A. nothing much would happen, and it would remain at approximately -65 mV.
- B. it would definitely be more negative than the normal resting potential.
- C. it would definitely be less negative than the normal resting potential.
- D. none of the above.
- E. it would loose its polarization and stand at exactly 0 mV (no difference between inside and outside of the neuron).
Answer: A.
Complete Marked out of 1.00 Which of the following statements is correct with regard to ionic concentrations at the normal resting membrane potential? Select one:
- A. higher sodium and potassium, and lower chloride inside relative to outside of neurons.
- B. lower sodium, potassium, and chloride inside relative to outside of neurons.
- C. lower sodium, and higher potassium and chloride inside relative to outside of neurons
- D. higher sodium, potassium, and chloride inside relative to outside of neurons.
- E. Lower sodium and chloride, and higher potassium inside relative to outside of neurons
Answer: A.
Complete Marked out of 1.00 At resting membrane potential, which of the following statements about the voltage-gated sodium ion (Na+) channels is TRUE? Select one:
- activation and inactivation gates are closed
- activation gates are closed and inactivation gates are open
- activation and inactivation gates are open
- activation and inactivation gates alternate between open and closed
- activation gates are open and inactivation gates are closed
Answer: A.