Why is muscle excitable tissue?

Answer 1

Muscle is excitable because it can be stimulated in order to cause contraction. Stimulation comes from the nervous system via electric signals/action potential that travels from neuron through axon to muscle tissue.

In-depth Details:

• Neuron sends action potential down its axon
• Once reaching the muscle tissue, the action potential stimulates release of Ach (acetylcholine)
• Ach crosses the synapse and binds to a muscle fiber (cell of muscle tissue),
• This stimulates action potential on the sacrolemma (plasma membrane of muscle cell)
• Action potential travels on the sacrolemma until it reaches a T-tubule
• Action goes down the T-tubule and into the muscle fiber
• This stimulates release of Ca2+ (calcium) from the sarcolemma
• Ca2+ binds with troponin
• Which stimulates tropomyosin to move out of the way so that actin and myosin can interact
• If ATP is available from mitochondria in muscle fiber, cross-bridge cycle occurs
• Contraction of muscle stops when the muscle is no longer stimulated from the nervous system