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: stores large amounts of glycosomes
Glycosome: provide glucose (sugar) during periods of muscle cell activity
Myoglobin: stores oxygen;Carry and store iron for muscle cells
Describe a myofibril
A myofibril is a bundle of contractile filaments (myofilaments), 1-2 μm in diameter, that are arranged in parallel groups in the cytoplasm of striated muscle cells. Why does a myofibril appear striated? Repeated presence of sarcomere on the myofibril. 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?