Neuromuscular Junctions. Physiology of Muscle Fibers. Action Potentials: The Role of Motor Neurons. Motor neurons produce motion by interacting with skeletal muscle. Electric signals called action potentials are sent along nerve cells to muscle fibers. Polarization of a neuron:.
Physiology of Muscle Fibers
Motor neurons produce motion by interacting with skeletal muscle.
Electric signals called action potentials are sent along nerve cells to muscle fibers.
This will eventually lead to a muscle contraction if the stimulus is above the threshold.
Botulinum toxin binds to pre-synaptic membranes at neuromuscular junctions, enters the neuron, and then a component of the toxin interferes with the release of neurotransmitter.Release of acetylcholine is blocked.No acetylcholine? No muscular contraction.(flaccid paralysis)
The Transverse (T) Tubules work with the sarcoplasmic reticulum to rapidly concentrate and move calcium ions throughout the sarcoplasm
Ca2+ binds the troponin molecules on the thin actinmyofilaments.
This leads to the ability of the thick myosin filaments to bind the actin.
The myosin heads pull the actin molecules inward, causing the whole fiber to shorten.
What is happening when ATP binds the myosin head?
The cross-bridge is broken and the muscle relaxes!