BIOL 2021 Lecture Notes - Lecture 8: Occipitofrontalis Muscle, Thoracic Cavity, Vastus Intermedius Muscle
25 Oct 2017
School
Department
Course
Professor
Document Summary
Origin: end of muscle attached to another structure in a fixed position. Insertion: end of muscle attached to structure that moves. Flexion: crosses on anterior side extension: crosses on posterior side. Abduction: crosses on lateral side adduction: crosses on medial side. Acts as fixator that stabilizes bone where agonist attaches. Antagonist: maintains body or limb position & controls rapid movement. Example: biceps flex the forearm, triceps extend it. The flexor digitorum superficialis & flexor digitorum profundus flex fingers & hands at wrist, extensor digitorum extends it. Fascicle arrangement correlated to force by muscle + range of motion. Fusiform: when a parallel muscle has a central large belly that is spindle shaped. Circular (sphincters): relaxed: concentrically arranged bundles increase size of opening. Convergent: fascicles come to a common attachment point when the muscle has a widespread expansion. Point could be a tendon, an aponeurosis (flat broad tendon) or raphe (slender tendon) Pennate: blend into tendon that runs through central region.
