Special Tactics Advanced Skills Training, Hurlburt Field, Fla. Advanced skills training is a 12-to-15-month program for newly assigned combat controller operators. AST produces mission-ready operators for the Air Force and U.S. Special Operations Command. The AST schedule is broken down into four phases: water, ground, employment and full mission profile.
Saltatory Conduction. As in un-myelinated axons, the first action potential in myelinated axons takes place at the initial segment of an axon and is generated by a threshold stimulus from the dendrites and cell body. Subsequent action potentials occur at the nodes of Ranvier, where the Na+ voltage-gated channels are located. Therefore, when nerve impulses travel down a myelinated axon, they appear to jump from node to node - in a process called saltatory conduction. Each nodal action potential is triggered by a threshold stimulus created by passive current from the previous node.
An action potential, which is the nerve impulse, occurs when a threshold is reached. Upon stimulation, the sodium gates open, Na+ flows into the axon, and the action potential swings up from -65mV to +40 mV.. The axon of a neuron conducts nerve impulses away from the cell body. Neurons that conduct messages from a sense organ to the central nervous system are called sensory, or afferent neurons. Those neurons that conduct an impulse from the CNS to a muscle or gland are called. motor, or efferent, neurons.