Muscular System

• Cardiac muscles are involuntary muscles found only in the heart.
• The cells of smooth muscle tissue are long and tapered at each end and have one nucleus
• Cardiac muscle forms to the wall of the heart and have tubular and striated cells
• Skeletal muscle contraction is voluntary and it is controlled by the nervous system
• Muscle fibres are organized into many large bundles
• Most of the volume of a muscle fibre consist of hundreds of thousands and cylindrical subunits called myofibrils
• Myofilament contains protein structures that are responsible for muscle contractions
• Actin myofilament consists of two strands or protein molecules that are wrapped around each other
• One end of a myosin myofilament consists a long rod; the other end consists a double-headed globular region
• Muscles shorten when contracting and can only pull
• Smooth muscles are nonstriated and are an involuntary tissue found in the walls of internal organs
• Cardiac muscles are striated, involuntary muscles that are found only in the heart
• Skeletal muscles are striated, voluntary muscle tissue and are usually attached to the bones
• Muscle fibers are skeletal muscle cells
• The sliding filament model is for muscle contraction based on the sliding actin filaments in relation to myosin filaments
• Sarcolemma is a membrane of a muscle fibre
• Summation is increased muscle contraction produced by the combination of stimuli
• Tetanus is a state of constant muscle contraction caused by sustained nerve impulse
• Myoglobin is an oxygen-binding pigment in a skeletal muscle fibre
• Sarcoplasma is cytoplasm of a muscle fibre
• Sarcoplasmic reticulum stores needed calcium ions needed for muscle contractions
• Muscle twitch is a single muscle contraction lasting a fraction of a second
• Glycogen and fat are stored in muscle cells for creatine phosphate breakdown
• Myoglobin temporarily stores oxygen and make it available to the mitochondria when cellular respiration begins
• Fermentation supplies ATP without consuming oxygen
• Oxygen deficit occurs when a muscle uses fermentation to supply its energy needs