How Skeletal Muscles Contract: Signals & Mechanisms

Signals from the central nervous system (CNS)

* Motor neurons are specialized nerve cells that carry signals from the CNS to skeletal muscles.

* Neurotransmitters are chemical messengers that transmit signals between neurons. The neurotransmitter that is released by motor neurons to stimulate skeletal muscles is acetylcholine (ACh).

Signals from within skeletal muscles

* Muscle spindles are sensory organs within skeletal muscles that detect changes in muscle length.

* Golgi tendon organs are sensory organs within tendons that detect changes in muscle tension.

* The stretch reflex is a reflex that helps to maintain muscle tone. It is triggered by signals from muscle spindles that indicate that a muscle is being stretched. The reflex causes the muscle to contract, which resists the stretch.

These are just some of the signals that control the movement of skeletal muscles. The CNS is ultimately responsible for controlling skeletal muscle movement, but it does so with the help of feedback from sensory organs within the muscles themselves.