Question

Compare and contrast electrical activity in an epithelial cell and a neuron. What anatomical structures produce the characteristics?

Answer 1

Epithelial cells are non-excitable cells. they maintain a stable equilibrium potential i.e. if currents are applied for a short period of time, the potential returns directly to its equilibrium value after the applied current is removed. Neurons are excitable cells. If the applied current is sufficiently strong (threshold), an action potential is developed, before eventually returning to rest.

Every cell in our body maintains an electric potential of magnitude -15 to -100 mV across the plasma membrane. The membrane potential exists because of a difference in the number of positive and negative charges across the membrane. These charges are attributed to the cations (positively charged ions) and anions (negatively charged ions) that occur on each side of the membrane. These ions pass through ion channels in cell membrane. These channels are highly regulated and specific for certain types of ions. The electric potential is mainly due to the movement of sodium ions (Na+) and potassium ions (K+) across the plasma membrane. In epithelial and other non-excitable cells, this electrical potential is called Membrane potential while In neurons, it is called Resting potential.

Neurons transmit information in the nervous system by the generation of electrical impulses. The electrical impulse used by nerve cells for the transmission of information is called an action potential. The action potential in neurons is manifested by potassium ions (K+) leak channels, voltage gated sodium ions (Na+) and potassium ions (K+) channels, and sodium/potassium antiport channels.