MRCP UK EXAMINATIONS

Detailed explanation-1: -The slow wave in gastric and intestinal smooth muscle is a periodic depolarization that sets up electrical conditions for smooth muscle cells to contract in response to the release of acetylcholine from the myenteric excitatory motor neurons. Accordingly, the smooth muscle cells contract only once during a slow wave.

Detailed explanation-2: -The resting membrane potential of smooth muscle cells is between-50 and-60 mV. In contrast to nerves and other types of muscle cells, the membrane potential of smooth muscle cells fluctuates spontaneously.

Detailed explanation-3: -Slow wave potentials are undulating changes in the resting membrane potential in gastrointestinal smooth muscle responsible for triggering an action potential. They do not cause smooth muscle contraction until they reach a threshold potential to trigger an action potential.

Detailed explanation-4: -The membrane of most gastrointestinal smooth muscles shows slow waves, slow rhythmic changes in membrane potential. Slow waves serve to bring the membrane potential of smooth muscle cells to a threshold level that elicits a second electrical event known as the spike or action potential.