110 likes | 348 Vues
Maximus, Minimus. Size. Rectus (straight), Obliqus. Biceps, Triceps. Direction. # of Origins. Origin Insertion. Muscle Names. Action. E.g. Sternocleidomastoid. Flexor, Extensor, Adductor. E.g. Tibialis anterior. Trapezius. Location. Shape. Muscle Terminology.
E N D
Maximus, Minimus Size Rectus (straight), Obliqus Biceps, Triceps Direction # of Origins Origin Insertion Muscle Names Action E.g. Sternocleidomastoid Flexor, Extensor, Adductor E.g. Tibialis anterior Trapezius Location Shape
Muscle Terminology • Firstly…..Muscles do only one thing actively…… • … Get Shorter! • ... Contract!
Prime Mover isthe muscle with the major responsibility when a group of muscles work together. • The Antagonists oppose or reverse a movement. • Note: When a prime mover is active the antagonist is stretched and relaxed. • E.g. Flexion vs. Extension
Each muscle has an Origin and an Insertion. • The Origin of a muscle is the stable part that doesn’t move the bone it is attached to while the Insertion moves the bone it is attached to. • E.g. O = hip I = anterior thigh The Function is to raise your leg (flexion of the hip)
Origin – Iliac Insertion – tendon of Psoas Action – Hip flexion, (with Psoas major) E.g. Iliacus
The Muscle Cell • Long and striated • (1-50 mm in length, 40-50 microns wide) • this is why they are called fibers • multi-nucleated • surrounded by an electrically polarized membrane called Sarcolemma
Contraction • a single nerve cell innervates 100-200 fibres • the nerve and muscle cells are called motor units • Motor units contract in an all-or-none principle
Types of Contraction • Isotonic – muscle changes in length • Isometric – muscle remains at the same length