Anatomy and Physiology - Muscular System Test with correct answers 2024

A sarcomere is best described as _______ - correct answer a unit within a myofibril Myofibrils are composed primarily of - correct answer actin and myosin A motor unit typically includes - correct answer one motor neuron and several muscle fibers Endomysium separates individual muscle fibers from each other. - correct answer True A motor neuron and the muscle fibers that it controls constitute a motor unit. - correct answer True A broad sheet of dense connective tissue that connects muscle to muscle is called - correct answer aponeurosis The electrical impulse that triggers a contraction travels deep into a skeletal muscle fiber by means of - correct answer transverse tubules Neurotransmitter molecules are stored in vesicles within - correct answer motor neuron endings The enzyme acetylcholinesterase causes acetylcholine to - correct answer decompose Creatine phosphate - correct answer supplies energy for the synthesis of ATP Binding sites on the surface of actin allow the formation of cross bridges with molecules of - correct answer myosin The amount of oxygen needed to support the conversion of lactic acid to glucose by the liver is called the - correct answer oxygen debt A muscle cramp is most likely due to a temporary lack of - correct answer ATP In the initiation of muscle contraction, calcium ions bind to tropomyosin, exposing active sites on actin for cross-bridge formation. - correct answer False The enzyme ATPase occurs in the globular portion of myosin molecules. - correct answer True Ach released by a motor neuron crosses the synaptic cleft and reaches the motor end plate by diffusion. - correct answer True The characteristic reddish brown color of skeletal muscle comes from which substance? - correct answer myoglobin An example of a partial but sustained contraction of a whole muscle is - correct answer muscle tone The threshold stimulus is the - correct answer minimum strength of stimulus required to cause muscle fiber contraction to occur Rigor mortis that occurs in skeletal muscles a few hours after death is due to - correct answer lack of ATP increased membrane permeability to calcium ions ATP is necessary for muscle relaxation. - correct answer True During anaerobic respiration, pyruvic acid molecules are converted into molecules of - correct answer lactic acid Anaerobic muscle fatigue is most likely due to an accumulation of - correct answer lactic acid The increase in the number of motor units activated as a result of more intense stimulation is called - correct answer recruitment In a recording of a muscle twitch, the delay between the time a stimulus is applied and the time the muscle responds is called the - correct answer latent period Activities such as distance swimming and distance running are most likely to stimulate development of - correct answer slow fatigue-resistant muscle fibers When a muscle undergoes atrophy in response to disuse, - correct answer All of the answer choices are correct. The minimal strength of stimulation needed to elicit a muscle contraction is called the threshold stimulus. - correct answer True