muscular system

• Skeletal: contraction produces body movement
• Smooth: contraction pushes fluid and solids through internal organs
• Cardiac: contraction pumps blood through cardiovascular
• Sarcoplasm is the cytoplasm of a muscle fibre
• Sarcolemma is the plasma membrane
• Resting membrane potential of a skeletal muscle cell is -85mV
• Myofibrils: long fibres which run parallel to each other
• Myofilaments: thin and thick filaments
• Thin filaments: consist of the proteins actin, troponin, and tropomyosin
• Thick filaments: consist primarily of the protein myosin
• Sarcoplasmic reticulum: tubular network around each myofibril where calcium is released from terminal cisterna into the cytosol
• Transverse tubules: conduct the electrical signal (action potential) from the sarcolemma into the muscle fibre causing contractions
• Factors influencing singular muscle tension: 1. Sarcomere length: long length doesn't allow for much overlap between thin and thick filaments - little force created 2. Stimulation frequency: low frequency results in muscle twitches
• Factors influencing whole muscle tension: 1. Number of motor units that are active during the task 2. Type of muscle fibres that are present in the muscle 3.. Type of contraction that is being performed 4. Speed of muscle contraction and relaxation 5. Duration and intensity of muscle contraction