PHYSIOL 1 Lecture Notes - Lecture 9: Endoplasmic Reticulum, Myocyte, Skeletal Muscle
Document Summary
Striated muscle attached to bones of the skeleton by tendons: origin: closest to trunk or to more stationary bone, insertion: more distal or more mobile attachment. Control body movement & gives voluntary control; responds to somatic motor neurons. Flexor-extensor pairs form antagonistic muscle groups: move bones in opposite directions bc muscle contraction can only push on a bone not pull back. Skeletal muscles are composed of muscle fibers: they are long & cylindrical & fused cells have many nuclei. Fiber bundled into fascicles surrounded by connective tissue sheath. Connective tissue surrounds entire muscle: differentiate into muscle for growth or repair, continuous with connective tissue sheath, holds muscle to bone with tendon. Primary muscle of internal organs and tubes. Influence movement of material into and out and within body. Involuntary control; responds to autonomic innervation, spontaneous contraction, modulated by endocrine system. Skeletal: fibers are large, cells appear striped or striated. Smooth: fibers are small and lack striations.
