8.3 Muscular System

If a muscle is exercised for a prolonged period and loses its ability to contract it is called muscle ___________.

Fatigue

_________________________ is the amount of oxygen needed for liver to convert accumulated lactic acid into glucose.

Oxygen Debt

The gap between the nerve ending and the muscle cell is the ________________________________________ where a chemical or ____________________________is released.

Synaptic cleft, neruotransmitter

Energy is provided for muscle contraction by _______________and its regeneration by direct phosphorylation by _______________________________________. This can last about 20 seconds.

ATP, creatine phosphate

When the nerve impulse reaches the nerve ending, the specific neurotransmitter called, _____________________________ is released.

Acetylcholine

The electrical current generated along the muscle cell's membrane is called a(n) ________________________ and it is the signal to trigger contraction.

Action potential

Most energy at rest and with light exercise is provided by __________________________________________, using glucose and other nutrient fuels.

Aerobic respiration

With intense exercise, _________________________________________________ and lactic acid formation occur.

Anaerobic respiration

This chemical binds to the muscle cell membrane causing a temporary rush of _____________________ ions into the muscle cell.

Calcium

In order for a muscle ______________________ to occur a motor neuron must send a(n) ________________ through the axon to the motor end plate.

Contraction, nerve impulse

Buildup of ______________________________ leads to fatigue and a burning sensation in the muscles and oxygen debt, but quickly goes away when activity slows down.

Lactic acid

One neuron and all the skeletal muscle cells it stimulates make up one _______________________________.

Motor unit

The position on the muscle cell where the nerve fiber connects is called the ____________________________ ___________________.

Neuromuscular junction