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 solving the many problems which confronted him." During the Japanese Attack on Pearl Harbor on December 7, 1941, Bone was stationed on Hawaii and coordinated the trucks with ammunition. In May 1942, Bone was transferred to the staff of South Pacific Island Base Inspection Board under Rear Admiral Richard E. Byrd and travelled to the South Pacific Area as a member of the inspecting party. He was promoted to the rank of colonel on July 24, 1942. During September of that year, Bone was transferred to Washington, D.C. and appointed Chief of the Gunnery Section, Division of Plans and Policies