Complete List of Terms and Definitions for Lecture - Muscle

Terms Definitions
contractile proteins actin and myosin
10,00-meter skatingcross-country skiingmarathon rumjogging Aerobic system
Aponeurosis Tendon, when the connective tissue elements extend as a broad flat layer
Curare A poison that blocks neuromuscular transmission by binding to acetylcholine receptors. Acetylcholine cannot bind to the blocked receptors, resulting in paralysis.'Can reverse: Anticholinesterases such as neostigmine, which increase the concentration at of acetylcholine at the neuromuscular junction.
Myofibril The contracting element of skeletal and cardiac muscle. Myofibrils consist of repeating assemblies of protein myofilaments.
Three phases of twitch Latent periodperiod of contractionperiod of relaxation
Black widow venom (latrotoxin) explosive release of AcCh
Titin is a giant protein expressed in cardiac and skeletal muscle that spans half of the sarcomere from the Z-line to M-line. Titin plays plays a key role in muscle assembly, force transmission at the Z-line, and maintenance of the resting tension in the I-ban region. It also contributes to the elastic recoil of a muscle that have been stretched.
Topomyosin a filamentous protein that winds over the surface of the actin filament, and which obstructs the binding of myosin to actin in the resting muscle.
Nerve gases (Saran, Soman, Tabun) block acetylcholinesterase-increase AcCH, causing constant stimulation of muscles and and asphyxiation.
Motor end plate At neuromuscular junction, the sarcolemma is modified to form a motor end plate.
Actin Composes the thin filaments. One end of an actin molecule is attached to a Z-line, that extends across the muscle fiber. The segment of myofibril lying between two Z-lines is called a sarcomere
Slow Oxidative Fibers Depends on Oxygen Deliveryred fibers, the smallest of the fiber typesabundant in muscles used to maintain posture
Acetylcholine receptor molecule The acetylcholine molecules then bind to specific acetylcholine receptor molecules in the sarcolemma of the motor end plate.
Oxygen Supply Creatine phosphate is the major source of energy during the 8-10 seconds of 100-meter sprint. After that time, however, the muscles beome dependent on cellular metabolism as a source of energy for synthesizing more ATP.
Excitation-contraction Coupling Muscle contaction is initiated by a rise in intracellular calcium ions, mediated by the two actin associated proteins troponin and tropomyosin.
Fast oxidative/glycolytic fibers fast acting myosin ATPases and depend upon anaerobic metabolism during contractionabundant glycogenmarathon runners
Properties of muscle cells -Muscle cells are bundled into fascicles-Muscle cells are packed with myofibrils-Myofribrils contain thick and thin myofilaments (filaments)-Myofilaments consist of a number of different proteins involved in the process of of contraction.
Creatine Over 95% of total creatine is found in skeleton muscle. Meat and fish are dietary sources of creatine, which can also be synthesized in the body from the amino acids arginine, glycine, and methionine. useless for endurance
Desmin and the microtubules That maintain the structural order within the cell and connect the cytoplasm and all cellular organelles with the sarcolemma
Excitation in Cardiac Muscle comparatively large amounts of calcium ions enter the muscle cells through the T-tubule membranes. This calcium then acts to trigger release of more calcium ions from the sarcoplasmic reticulum.The contation of cardiac muscle, therefore, is mucho more dependent on calium ions in the external medium than the contraction of skeletal muscle.
Thin Filaments I band and partway into the A band (Actin)
Calcium in contraction the coupling of the nerce impulse with muscle contraction hinges around the release of calcium ions that are stored within the sarcoplasmic reticulum, and the effect of the calcium ions on toponin and topomyosin.
Properties of muscle fibers or myofibers -contract and generate force-stretch when an opposing muscle contracts -return to their original length after stretching - that is, they are elastic-contact when stimulated by a neuron.
Creatine phosphate pool of energy stored in the cell. The enzyme creatine phosphkinase transfers the high-energy phosphate group of creatine phosphate to ADP, so generating more ATP for immediate use. This is known as the phosphagen system.creatine phosphate + ADP ----> cretine + ATP
Neuromuscular junction The junction of an axon with a muscle fiber is a specialized structure called the neuromuscular junction.
Excitation-contraction Step 3 The result is a sharp rise in the concentration of calcium ions in the sarcoplasm. The rise of sarcoplasmic calcium ion concentration enables the first phase of muscle contraction- attachment of the primed myosin heads to actin.
Fast, Glycolytic (White) Fibers (Type II) Fast, white fibers carry our rapid, forceful movements-they generate anaerobic and are susceptible to fatigue.