ACh induces which of the following in skeletal muscle?

Acetylcholine (ACh) plays a crucial role in the physiology of skeletal muscle contraction. When ACh is released from the motor neuron at the neuromuscular junction, it binds to nicotinic acetylcholine receptors on the muscle cell membrane (sarcolemma). This binding opens ion channels, allowing sodium ions to flow into the muscle cell. The influx of sodium ions generates an action potential in the muscle fiber.

This action potential then travels along the sarcolemma and down into the muscle fiber through the T-tubules, ultimately triggering the release of calcium ions from the sarcoplasmic reticulum. The increase in intracellular calcium concentration leads to the interaction of actin and myosin filaments, resulting in muscle contraction through the sliding filament model.

Thus, acetylcholine's primary action in skeletal muscle is to induce contraction, making this the correct answer. Other processes such as lactate production, relaxation, and dehydration are not directly induced by ACh in the context of skeletal muscle function.