KIN 121 Lecture Notes - Lecture 10: Multinucleate, Myofilament, T-Tubule
Document Summary
Muscles convert chemical energy into mechanical work. Cardiac muscle (involuntary: blood vessels, organs, eye iris, uniform contractions, fatigue resistant, self generating impulses, features both smooth and ______ muscle tissue, very fatigue resistant, connects bony segments via tendons, repeated contractions leads to fatigue, voluntary, anatomy: Connective tissue- comprised mostly of the protein collagen. Sometimes the tendon is in the form of broad sheets called fascia. Sarcomere- functional unit (where a contraction takes place)- section of myofibril. Sarcoplasmic reticulum = (net-like) labyrinth of tubules inside fibre. T-tubules (transverse tubules)- connect sarcoplasmic reticulum with outer. A muscle fibre contains many myofibrils made up of the contractile proteins from z units membrane (sarcolemma) (myofilaments: actin (thin filaments)- forms the framework, myosin (thick filaments) Sliding filament theory (classic contraction: the myofilament or contractile protein actin slides across myosin, a muscle contraction = many sarcomeres shortening. Isometric state- when muscle force equals the load, the muscle will not change length.
