Chapter 9 Questions Flashcards
What’s the synapse where a motor neuron axon and skeletal muscle fiber meet
Neuromuscular junction
What is a chemical stored it synaptic vesicles
Neurotransmitter
What when stimulated by a nerve impulse, is released into the gap at the motor end plates and stimulates the fiber to contract
Neurotransmitter
What neurotransmitter uses motor neurons to control skeletal muscle contraction
ACh
What happens when action potential reaches he end of the axon?
Vesicles release ACh into the synaptic cleft
What results from ACh diffusing rapidly across the synaptic cleft and binding to specific proteins molecules in the muscle fiber membrane
Increase in the membrane permeability to sodium ions
What causes membrane permeability to sodium and potassium ions increasing temporarily in a pattern that results in positive sodium ions entering and potassium ions leaving the muscle cell
Motor neuron stimulating a cell
What is action potential
Result of the ion movements a bioelectrixal current
What triggers the release of calcium ions from the sarcoplasmic reticulum leading to muscle contraction
Electrical impulse
Describe skeletal muscle fiber contraction
Action potentiometer conducted down a motor neuron axon, then releases ACh. ACh binds to receptors on muscle fiber. Sarcolemma is stimulated, actions potential is generated and the impulse is conducted over the surface of he muscle fiber and deep into the fiber through transverse tubules. Impulse reaches the sarcoplasmic reticulum and calcium channels open. Calcium ions diffuse from there into the sarcoplasmic and bind to troponin. Tropomyosin moves and exposes specific sites on actin. Actin and myosin kink forming crossbridges. Thin acting filaments pull toward the center of the sarcomere by myosin cross ridges increase the overlap of thin and thick filaments. Muscle contracts.
What’s the intial source of energy available to regenerate ATP from ADP phosphate
Creatine phosphate
During exercise what is used to synthesize ATP for muscle contraction
Oxygen
What is accumulated lactic acid
Oxygen debt
What is made up of a motor neuron and muscles fibers it controls
Motor unit
What are muscle fibers less organized and function as separate units
Multi unit smooth muscle muscle movement
