2.1

Where does voluntary movement begin?

All voluntary movement begins in the brain where sensory information from the body is received, integrated, and processed

What do upper motor neurons do?

carry the command signal from the brain down through the central nervous system

What happens when the signal leaves the CNS?

The signal enters the peripheral nervous system and synapses with a lower motor neuron usually an alpha motor neuron

How is the signal from the brain carried to the alpha motor neuron?

It travels as electrical signals called action potentials

What happens when the action potential reaches the end of the alpha motor neuron?

Synaptic vesicles release the neurotransmitter acetylcholine

What happens to acetylcholine at the neuromuscular junction?

Acetylcholine diffuses across the synaptic cleft and binds to nicotinic acetylcholine receptors on the sarcolemma of the muscle fiber

What happens when acetylcholine binds to its receptors?

Ion movement across the sarcolemma generates a new electrical signal in the muscle fiber

What type of signal conversions occur during excitation contraction coupling?

Electrical signal in the neuron chemical signal across the synapse and electrical signal again in the muscle fiber

What is excitation contraction coupling?

The process where a signal from the nervous system triggers contraction in a muscle fiber

What analogy can describe signal conversion between nerve and muscle?

It is like a currency exchange where the signal changes form from electrical to chemical and back to electrical