PS263 Chapter Notes - Chapter 7: Golgi Tendon Organ, Neuromuscular Junction, Tendon Reflex
Document Summary
Most of our body movements are controlled by skeletal muscles. Sensorimotor spinal circuits hundreds or thousands of muscle fibers. Groups of these muscle fibers are innervated by a single motor neuron. Such an arrangement is called a motor unit. Acetylcholine is the neurotransmitter released by motor neurons at the neuromuscular junction. Acetylcholine activates the motor end-plate -the receptive area on a muscle fiber at the neuromuscular junction -causing it to contract. The term motor pool is used to describe the collection of motor neurons that innervate the fibers of a single muscle. There are two general classifications of skeletal muscles: either they are flexors (act to bend or flex a joint) or extensors (act to straighten or extend a joint). Any two muscles (like the bicep and the tri- cep) that act in opposite directions are called antagonistic, whereas muscles that act together are said to be synergistic.
