Extrafusal muscle fiber Extrafusal muscle fiber Extrafusal muscle fibers are the skeletal standard muscle fibers that are innervated by alpha motor neurons and generate tension by contracting, thereby allowing for skeletal movement. They make up the large mass of skeletal muscle tissue and are attached to bone by fibrous tissue extensions (tendons). Each alpha motor neuron and the extrafusal muscle fibers innervated by it make up a motor unit. The connection between the alpha motor neuron and the extrafusal muscle fiber is a neuromuscular junction, where the neuron's signal, the action potential, is transduced to the muscle fiber by the neurotransmitter acetylcholine. Extrafusal
Bertram A. Bone capacity, he was responsible for the recruit training of all new marines on the West Coast of the United States. When Marine Corps Base San Diego was redesignated Marine Corps Recruit Depot in January 1948, Bone was appointed assistant chief of staff for operations and training. He served in this capacity until his retirement on June 30, 1949. Bone was advanced to the rank of brigadier general for having been specially commended in combat. He settled in his native San Diego and died on October 22, 1961. Bone is buried at Fort Sam Houston National Cemetery together with his wife,