Title: A&P 1 ch 9 & 10 Flashcards | Quizlet
Headings: A&P 1 ch 9 & 10
A&P 1 ch 9 & 10
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A&P Ch 9
Chapter 9
Bones of the Lower Leg
Bones

Content: What is a sarcomere
A sarcomere is the area between two Z discs. Describe a triad, and list the functions of the two structures within the triad
Successive grouping of the 3 membranous (terminal cistern, T tubule, and terminal cistern) along the sarcoplasmic reticulum. T-tubules conduct impulses to the deepest regions of the muscle cell and every sarcomere. Terminal cistern produce energy during contraction
Explain how muscle fibers are stimulated to contract by describing the events at the neuromuscular junction
Skeletal muscles are stimulated by somatic motor neurons Axons of motor neurons travel from the central nervous system via nerves to skeletal muscles Each axon forms several branches as it enters a muscle Each axon ending forms a neuromuscular junction with a single muscle fiber
Describe how an action potential is generated and moves from the motor neuron to the muscle fiber
End plate potential spreads to adjacent membrane areas
>Voltage-gated Na+ channels open
>Na+ influx decreases the membrane voltage toward a critical threshold
>If threshold is reached, an action potential is generated
>Local depolarization wave continues to spread, changing the permeability of the sarcolemma
Follow and describe the events of excitation-contraction coupling that lead to cross bridge cycling
Sequence of events by which transmission of an AP along the sarcolemma leads to sliding of the myofilaments
> Latent period: > Time when E-C coupling events occur
> Time between AP initiation and the beginning of contraction
> AP is propagated along sarcomere to T tubules
> Voltage-sensitive proteins stimulate
> Ca2+ release from SR
> Ca2+ is necessary for contraction
What is the role (s) of calcium, sodium (Na) and postassium (K) within a muscle contraction? Calcium-Muscle contraction is regulated by calcium ions, which will change thin filament into an activated state by binding to troponin. The binding of calcium to the troponin changes it's shape so the myosin binding sites on the actin (thin filament) are exposed
Sodium-
What is the role of acetylcholine (Ach) within a muscle contraction? When released ACh binds to receptors on the motor end plate, changing its permeability to Na+ ions. Na+ ions (due to an increased electrochemical gradient) rush into the sarcolemma. Be able to identify the function of any structure within the muscle contraction sequence?