lecture23-Aging Muscle Navazio

lecture23-Aging Muscle Navazio - Aging of Skeletal Muscle...

Info iconThis preview shows pages 1–11. Sign up to view the full content.

View Full Document Right Arrow Icon
Aging of Skeletal Muscle Dr. Franco Navazio
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Muscles There are 660 skeletal muscles in adult humans These constitute 45% to 50% of the normal body weight Their primary purpose is to provide “MOTILITY” In addition, they represent the major site for: - energy transduction - energy storage - primary support system
Background image of page 2
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Anatomy Skeletal muscle is composed of Muscle fascicles are composed of Muscle fibers (multinucleated cells, the longest in the body) Each fiber is composed of MYOFIBRILS and, within the myofibril structure, the contracting machinery is the SARCOMERE Sarcomeres are composed of digital thin filaments, the ACTINS, ” and interdigitated thick filaments: the MYOSINS Titins - represent the tract along which actin and myosin superimpose during contraction
Background image of page 4
Anatomy 2 membranes surround the muscles: outer membrane : the basement membrane (very permeable to solutes and proteins or to other metabolites) inner membrane : SARCOLEMMA is located just beneath the plasma membrane (a true cell boundary) An intact sarcolemma is critically important: it maintains a proper acid-base balance of the fibers propagates the action potential (starting at the neuromuscular plaque leading to the muscle contraction) Permits the passage of Ca++ in two direction in for contraction out for relaxation
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Contraction The actors: Ca ++ passes through the sarcolemma; in its presence there is hydrolysis of ATP (ADP+P) which releases energy ADP binds to ACTIN : meanwhile, a regulatory protein (enzyme) TROPONIN (activated by this energy) binds to MYOSIN forming TROPOMYOSIN--shifting the ACTIN helix and leading to CONTRACTION End result: the ACTOMYOSIN complex Contraction could involve lengthening or shortening mechanisms, depending on the movement pattern MEMO the TETANIC contraction
Background image of page 6
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 8
Background image of page 9

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
GENDER EFFECT In both sexes, strength can only be obtained after myelination of the afferent nerves , reached at maturity. Maximum gain in muscle strength
Background image of page 10
Image of page 11
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 04/02/2008 for the course MCB 135k taught by Professor Timiras during the Spring '08 term at University of California, Berkeley.

Page1 / 25

lecture23-Aging Muscle Navazio - Aging of Skeletal Muscle...

This preview shows document pages 1 - 11. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online