Stimulation of skeletal muscle fibers

in order for a muscle to contract, its fibers must first be—-

stimulated by a motor neuron

The site where a motor neuron and a muscle fiber meet BUT DO NOT TOUCH

Neuromuscular junction

One motor neuron and many skeletal muscles

Motor unit

Each motor neuron may stimulate —— of muscle fibers

a few or hundreds

Each—-forms junctions with the motor endplates of different muscle fibers

Axon terminal

The—-of the muscle fiber is specialized to form a motor end-plate

sarcolemma

The specific part of a skeletal muscle fiber’s sarcolemma directly beneath the NMJ

Motor end-plate

Gap between the motor neuron and a muscle

Synaptic cleft

Chemical substance released from a motor end fiber, causing stimulation of the sarcolemma of muscle fiber

Neurotransmitter

Which neurotransmitter stimulates the sarcolemma of the muscle fiber?

Acetylcholine

ACh is stored where in the axon?

synaptic vesicles

Eats ACh to initiate the relaxation of the muscle

Acetylcholinesterase

ACh can’t be activated without—-

Calcium

Once ACh has binded to the motor end plate what happens?

Electrical membrane sends a message to myofibril

After message is sent to myofibril what happens?

Causes SR to release calcium

When the motor impulse reaches the end of the motor nerve fiber/ending the membrane is—-

depolarized and becomes permeable to calcium ions

After ACh diffuses across the NMJ what happens to the motor end-plate(sarcolemma)?

Becomes depolarized

After the sarcolemma is depolarized, what does it become permeable to?

Na ions

How does a muscle impulse travel over there surface of the sarcolemma and deep into the muscle fiber?

Through the transverse tubules

The muscle impulse reaches the SR, which releases calcium ions into the sarcoplasm of the muscle fiber

excitation contraction coupling

What is required for calcium to be released?

sodium