BIO 192 Exam 2 NAU Questions and Answers well Explained Latest 2024/2025 Update 100% Correct.

What type of muscle fiber fiber has the most mitcochondria - type 1, slow-oxidative, slow what muscle fiber type is the least efficient - type IIb, fast-oxidative glycolytic, fast which muscle fiber type has mixed metabolism - type IIa, fast glycolytic, intermediate 3 Traits of Skeletal Muscle - Striated Multi Nuclei Voluntary 3 Traits of Cardiac Muscle - Striated Single Nuclei Involuntary 3 Traits of Smooth Muscle - Smooth Single Nuclei Involuntary What are the 2 main branches of the nervous system - central nervous system and peripheral nervous system What does the CNS include - Brain and spinal cord What does the PNS include - afferent (sensory) and efferent (motor) Efferent expands to - Autonomic - cardiac and smoothSomatic - skeletal Connects bone to muscle - Tendon Epimysium - connective tissue around whole muscle Perimysium - Connective tissue surrounding a fascicle endomysium - Connective tissue surrounding a muscle fiber fascicle - bundle of muscle fibers myofibrils - make up muscle fibers sarcolemma - muscle cell plasma membrane sarcoplasmic reticulum - modified ER, stores calcium sarcoplasm - cytoplasm of a muscle cell function of t tubules - increase surface area on muscle fiber, passageways for calcium and signals Neurotransmitter - a chemical substance that is released at the end of a nerve floor by arrival of a nerve signal. diffuses across synapse transferring signal to the muscle sarcomere - functional unit of muscle, one z-line to the next myosin v actin - myosin (thick filament) and actin (thin filament)excitation-contraction coupling - 1. arrival of nerve signal 2. Ach is released from motor neuron 3. Ach binds to sarcolemma of muscle fiber 4. NA+ in (depolarization), K+ out (repolarization) 5. Action potential 6. Ca+ leave SR 7. Ca+ binds to troponin, shifts 8. tropomyosin also shifts, exposing binding sites 9. myosin heads bind to actin 10. powerstroke 11. continued cross-bridge cycling, cross bridges break 12. nerve signal stops, relax 13. Ca+ returns to sarcoplasmic reticulum 14. Tropomyosin covers binding sites motor unit - one motor neuron and all the muscle fibers it innervates Fine motor control: high or low innervation ratio? give example - low, hand muscles gross motor control: high or low innervation ratio? give example - high, thigh muscles what changes the plasticity of muscles - fiber size (hypertrophy & atrophy) biochemical composition (enzymes) with aerobic training, type IIb fibers shift to what - type IIa, intermediatewhat determines strength - muscle size & fiber recruitment what order are muscle fibers recruited in - slow, intermediate, fast more recruited fibers, more force eccentric - muscle lengthens concentric - muscle shortens isometric - static, same length isokinetic - same speed