ADSC 4300 Lecture Notes - Lecture 7: Alpha Motor Neuron, Myofibril, Sarcomere

• School: University of Georgia
• Department: Animal and Dairy Sciences
• Course: ADSC 4300
• Professor: Liu

Document Summary

There are a lot of muscle fibers within one muscle. Muscle plasticity: these muscle fibers are organized by connective tissue: epimysium, perimysium, single muscle fiber is wrapped with endomysium. One myofibril is a chain of sarcomere which is the smallest contractile unit. Each muscle fiber is innervated by 1 nerve ending: motor neurons: alpha, beta, and gamma, red fibers can be innervated by alpha or beta motor neurons. Muscle fibers: red vs white: muscle color can be different. Color is determined by the abundance of myoglobin (oxygen & iron binding protein) If a muscle has more red muscle fibers than white, the muscle is read: muscle appearance is based on the ratio of 2 types of fibers (red & white, red muscle fibers: high mitochondrial content, mixed muscle fibers: Contractile speed: speed of contraction is related to inherent atpase activity & type of myosin inform present, slow twitch (type 1, red, betar, fast twitch (type 2, white, alphaw)