Biological complexity: muscle electrical grid (Introduction)

by David Turell , Thursday, August 06, 2015, 00:10 (3398 days ago) @ David Turell

It is made up of mitochondria in a grid formation to provide immediate energy to muscle movement as needed.:-http://www.nih.gov/news/health/jul2015/nhlbi-30.htm-"A new study overturns longstanding scientific ideas regarding how energy is distributed within muscles for powering movement. Scientists are reporting the first clear evidence that muscle cells distribute energy primarily by the rapid conduction of electrical charges through a vast, interconnected network of mitochondria — the cell's “powerhouse” — in a way that resembles the wire grid that distributes power throughout a city. The study offers an unprecedented, detailed look at the distribution system that rapidly provides energy throughout the cell where it is needed for muscle contraction. -***-"The movement of muscles, from flexing your arms to the pumping of the heart, requires lots of energy that must be distributed throughout the cell. For example, the skeletal muscle rate of energy utilization can increase 100-fold with strenuous exercise. As a result, muscle cells contain many mitochondria, microscopic structures that are specially equipped to convert foods, including sugars and fats, into useable high-energy molecules, particularly adenosine triphosphate (ATP), for work. As part of this process, known as oxidative phosphorylation, the mitochondria, like small cellular batteries, use an electrical voltage across their membranes as an intermediate energy source in converting food into ATP. Thus, this mitochondrial membrane voltage can be considered one of the primary sources of energy in the cell.-***-"The study provides unprecedented images of how these mitochondria are arranged in muscle. “Structurally, the mitochondria are arranged in such a way that permits the flow of potential energy in the form of the mitochondrial membrane voltage throughout the cell to power ATP production and subsequent muscle contraction, or movement,” Dr. Balaban explained. Mitochondria located on the edges of the muscle cell near blood vessels and oxygen supply are optimized for generating the mitochondrial membrane voltage, while the interconnected mitochondria deep in the muscle are optimized for using the voltage to produce ATP, Balaban added.-“'These observations solve the problem of how muscle rapidly distributes energy in the cell for movement,” Dr. Balaban said. “The findings also challenge the older model that energy is distributed by the slow diffusion of high-energy molecules through the remarkably dense muscle cell.'”