Order the following steps in the generation and propagation of an action potential at a neuromuscular junction: (i) Ion gates open, changing sarcolemma permeability locally; (ii) ACh attaches to receptors on the sarcolemma; (iii) Depolarization propagates in unidirectional waves; (iv) Repolarization occurs as ion gates close.

Arrange the following brain wave patterns in the correct sequential order as an individual progresses from a state of alert wakefulness into the deepening stages of Non-REM sleep. A. Sleep spindles and K-complexes on a background of theta waves B. Very slow, high-amplitude delta waves C. High-frequency and low-amplitude jagged waveforms (beta waves) D. Transition from alpha waves to low-voltage theta waves Choose the correct answer from the options given below:

Which of the following types of nerve fibers has the lowest nerve impulse conduction velocity?