BIOL 5 - MUSCLES 0.0 / 5 ? BiologyHuman, animal and plant physiologyA2/A-levelAQA Created by: RabiaCreated on: 08-03-14 18:17 Muscle fibre cell surface membrane Sarcolemma 1 of 22 Myofibrils Protein strands which cause contraction 2 of 22 I Band Just actin 3 of 22 A Band Actin and myosin 4 of 22 H Zone Just myosin 5 of 22 Actin Thin filament, has binding sites for myosin which are covered by TROPOMYOSIN when the muscle is relaxed 6 of 22 Myosin Thick filament, head of myosin extends out and contains ATP and ATPase on the actin binding site 7 of 22 Calcium ions released from the _____ Sarcoplasmic reticulum 8 of 22 Role of calcium ions Bind to tropomyosin and move it from the binding site, activate the ATPase 9 of 22 ATPase role Hydrolyses the ATP on the binding site so a cross bridge can form between actin and myosin - also provide the energy for power stroke 10 of 22 I band during contraction Narrows 11 of 22 A band during contraction Stays the same 12 of 22 Outer edges of the dark bands during contraction Widens 13 of 22 H zone during contraction Narrows 14 of 22 Neurotransmitter released at motor end plate Always acetylcholine 15 of 22 EPPs End plate potentials 16 of 22 Action potential travels down the ____ which connect to the ________ T-tubules which connect to the sarcoplasmic reticulum 17 of 22 Acetylcholine is broken down by ________ and is _______ Acetylcholinesterase and actively transported back to the pre synaptic membrane 18 of 22 Slow muscle fibres Contract slowly, many mitochondria, aerobic respiration, high resistance to fatigue, myoglobin, low stores of glycogen 19 of 22 Fast muscle fibres Contract quickly, few mitochondria, anaerobic respiration, low resistance to fatigue, many glycogen stores, no myoglobin 20 of 22 3 METHODS OF ENERGY SUPPLY DURING CONTRACTION 1)Aerobic respiration 2)Anaerobic 3)Phosphocreatine system 21 of 22 Equation for ATP/CP System Phosphocreatine + ADP = ATP + Creatine 22 of 22
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