Question

Neurons, by some estimates, spend up to 40% of their energy maintaining a resting membrane potential of about −70mV. Why is this a worthwhile investment? What would be the impact on our behavior if the resting membrane potential was shifted either more negative, to about −90mV, or more positive, to about −65mV?

a) Increased neural efficiency
b) Enhanced neurotransmitter release
c) Impaired neural function
d) Reduced action potential frequency

Answer 1

Maintaining a resting membrane potential around -70mV is crucial for neuron function. Shifts to either -90mV or -65mV could lead to impaired neural function by respectively decreasing or increasing action potential frequency beyond normal function.

Step-by-step explanation:

Neurons spend a significant amount of energy, sometimes up to 40%, maintaining a resting membrane potential of approximately -70mV, which is a worthwhile investment because it's fundamental for the function of neurons. This potential is essential for the generation of action potentials, which are critical for neural communication. If the resting membrane potential were altered to -90mV, the neurons would be hyperpolarized, leading to a decrease in action potential frequency or even complete silencing of neuronal activity. Conversely, shifting the potential to -65mV would cause neurons to be closer to the threshold for action potentials, potentially resulting in increased and possibly uncontrollable firing rates. Therefore, any significant shift from the -70mV resting potential could lead to impaired neural function (c), impacting everything from muscle control to cognitive abilities.