CSULB BIOL 207 Lab Final Study correctly answers graded A+

CSULB BIOL 207 Lab Final StudyWhat is the function of skeletal muscle? - correct answer Contracts to cause bone movement What are the structures of the skeletal muscle? - correct answer Tendons and muscle fibers What does muscle fibers contains? - correct answer Bundles of protein filaments What are the two protein filaments in muscle fibers? - correct answer Actin (Thin) and Myosin (Thick) What does the Sliding Filament Model state? - correct answer Actin and myosin DO NOT shorten, but instead slide past each other during contraction What is the smallest unite of contraction of inside muscle fibers? - correct answer Sarcomere What does it mean if the sarcomere is longer than usual? - correct answer The muscles fibers are relaxing What does it mean if the sarcomere is shorter than usual? - correct answer The muscle fibers are contracting What is the first step of muscle contraction? - correct answer The action potential travels down the motor neuron axon What does the action potential cause during muscle contraction? - correct answer Release acetylcholine and muscle depolarizes What happens at threshold during muscle contraction? - correct answer Voltage-gated Ca2+ channels in plasma membrane open and release the ions in sarcoplasmic reticulum to open What does the calcium bind and what happen after binding? - correct answer Tropnin; Causes tropomyosin to expose actin sites What happens when the actin sites are exposed? - correct answer Myosin heads bind to the actin and perform a power stroke which contracts the sarcomere How are nerves and muscles controlled? - correct answer Electrical impulses stimulate the nerves to send signals to the brain for contracting the target muscles. In the experiment, what is signaling contraction of the hand? - correct answer Artificial muscle stimulator Where do signals for muscle contraction normally originate? - correct answer Motor neurons What occurs during stimulation below threshold with artificial simulation? - correct answer No action potential occur -> no contraction What occurs when a single pulse of stimulation is at or above the threshold with artificial simulation? - correct answer 1 action potential -> a single & fast contraction called twitch occurs What is summation in artificial stimulation? - correct answer Second twitch that is built on the previous twitch What frequency causes summation to occur? - correct answer Medium What frequency causes a twitch to occur? - correct answer Low Why does summation occur? - correct answer Muscles have no time to relax before the next stimuli What is tetanus? - correct answer Smooth and sustained muscle contraction What frequency causes tetanus? - correct answer High