ECE_3820_lecture_5_2011

ECE_3820_lecture_5_2011 - Today (9/13), lecture #5 1) Quiz...

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Today (9/13), lecture #5 1) Quiz #2 (5 minutes) 2) Skeletal muscle physiology 3) Smooth muscle physiology Thursday (9/15), lecture #6 1) Biomedical engineering as a profession 2) Diffusion and mass transfer Annoucements 1) My belief is that the textbook mess has been cleaned up (for the most part). 2) Quizzes and exams will not be returned. Huda Asfour (the course grader) will be available on Tuesdays from 3-4pm in Ross Hall room 456 for you to view your quizzes and exams.
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Skeletal Muscle Physiology cont….
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Cross-bridge cycling
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ATP Ca Ca SR T-tubule Sarcolemma EXCITATION-CONTRACTION COUPLING IN SKELETAL MUSCLE Na + Ryanodine receptor Dihydropyridine receptor Troponin-C Excitation-contraction coupling in skeletal muscle Molecular link between the dihydropyridine receptor and the ryanodine receptor
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A single muscle contraction is called a twitch. 4 phases of a muscle twitch 1) Latent period (5msec): time b/w application of AP and initiation of contraction. 2) Contraction (40msec): muscle shortens and does work. 3) Relaxation (50msec): muscle elongates and returns to original position. 4) Refractory period (2msec): time of recovery between APs.
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Twitch summation increases force. Tetanus produces maximum force.
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Length – Tension relationship for skeletal muscle
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Muscle length Isometric tension 0.6L 0 1.4L 0 L 0 Length-Tension relationship for a skeletal muscle fiber. Passive stretch of muscle (not stimulated to contract) is governed by its structural mechanical properties. Active tension is governed by the cell’s ability to undergo crossbridge cycling. Total force developed during contraction is the sum of active and passive tension.
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Cytoskeleton structure of a muscle cell
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Muscular Dystrophy Gradual muscle wasting Progressive weakness
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This note was uploaded on 11/14/2011 for the course ECE 3820 taught by Professor Wang during the Fall '11 term at GWU.

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ECE_3820_lecture_5_2011 - Today (9/13), lecture #5 1) Quiz...

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