The Muscular System and Sliding Filament Theory

• Muscle types include Cardiac muscle (involuntary), Smooth muscle (involuntary), and Skeletal muscle (voluntary)
• Muscles can only "pull," they shorten when they contract and lengthen when they relax, working in pairs as agonist and antagonist muscles
• Muscle Categories include Flexors (bend a limb) and Extensors (straighten a limb), as well as Abductors and Adductors
• Muscle Anatomy consists of Origin (fixed end), Muscle Belly (thick part), and Insertion (moveable end), with energy used in muscle contraction lost as heat
• Myofilaments, like actin and myosin, are the contractile proteins in muscles, with sarcomeres containing Z lines, A Bands, I Bands, H Zone, and Cross bridges for muscle contraction
• Muscle Contraction occurs by actin sliding over myosin, with regulatory proteins like TROPONIN and TROPOMYOSIN aiding in the process
• Sliding Filament Theory explains muscle contraction through six major steps involving nervous stimulation, Ca2+ binding, myosin energization, active site bonding, powerstroke, and action potential removal
• Muscle Contraction strength is determined by Summation and Tetany, with different types of muscle fibers present in the body, including Type I (slow twitch), Type IIa (fast twitch), and Type IIx (fast twitch)
• Slow Twitch Fibers break down ATP slower, have more mitochondria and myoglobin, suited for endurance activities
• Fast Twitch Fibers break down ATP faster, have less mitochondria, rich in glycogen, and fatigue quicker, suited for sprinting and stop-and-go activities
• Sliding Filament Theory
• Cardiac muscle is involuntary, meaning it cannot be controlled consciously.
• Skeletal muscle is voluntary, meaning it can be controlled consciously.
• The skeletal muscles are attached to the bones by tendons.
• Smooth muscle is found in organs such as blood vessels, digestive tract, uterus, bladder, and iris of eyes.
• The muscular system consists of skeletal muscles that attach to bones via tendons, allowing movement at joints.
• There are three main types of muscle tissue: cardiac muscle, smooth muscle, and skeletal muscle.
• Tendon attachments allow movement at joints.
• Muscles contract when stimulated by nerve impulses from motor neurons.