Chamberlain bios 252 exam 1 Questions & Answers

skeletal muscle - ANSWERS- long, thin, cylindrical in shape - multinucleated - attached to bone & skin - voluntary - striated cardiac muscle - ANSWERS- short, fat, branched - uninucleated - in heart - attached to intercalated discs - involuntary - striated smooth muscle - ANSWERS- in hollow organs - ininucleated - involuntary - lack striations excitability - ANSWERSresponsiveness to chemical signals, stretch, and electrical changes across the plasma membrane conductivity - ANSWERSlocal electrical excitation sets off a wave of excitation that travels along the muscle fiber contractility - ANSWERSshortens when stim extensibility - ANSWERScapable of being stretched b/w contractions elasticity - ANSWERSreturns to its original rest length after being stretched organization of skeletal muscle - ANSWERSmicrofilaments, myofibril, muscle fiber, muscle fascicle, and skeletal muscle endomysium - ANSWERSthin sleeve of loose CT around each fiber perimysium - ANSWERSthicker layer of CT that wraps fascicles fascicles - ANSWERSbundles of muscle fibers wrapped together epimysium - ANSWERSfibrous sheath surrounding entire muscle what are the components of the sarcomere - ANSWERSz disc, m line, a band, i band, zone of overlap, thick filament, thin filament, zone of overlap, sarcomere z disc - ANSWERSnarrow, plate-shaped regions of dense materials that separate on sarcomere from the next a band - ANSWERSdark, middle part of sarcomere that extends entire length of thick filaments & includes those part of thin filaments that overlap thick filament s i band - ANSWERSlighter, less dense area of sarcomere that contains remainder of thin filaments but no thick filaments * z disc passes thru center of each I band h zone - ANSWERSnarrow region in center of each a band that contains thick filaments but no thin filaments m line - ANSWERSregion in center of h zone that contains proteins that hold thick filament together at center of sarcomere fibrous (F) actin - ANSWERS2 intertwined strands - string of globular (G) actin subunits each w/ active site that can bind head of myosin molecule troponin molecule - ANSWERSsmall, Ca2+- binding protein on each tropomyosin molecule 1st step of sliding filament theory - ANSWERSmyosin pulls on actin, causing thin filament to slide inward * ratchet along filaments 2nd step of sliding filament theory - ANSWERSz discs move towards each other, & sarcomere shortens 3rd step of sliding filament theory - ANSWERSthanks to structural proteins, there is a transmission of force throughout the entire muscle * resulting in whole muscle contraction 4th step of sliding filament theory - ANSWERSchanges in I band & H zone as muscle contracts how do muscles derive the ATP necessary to power contraction cycle? - ANSWERS1. hydrolysis of creatine phosphate 2. anaerobic glycolysis 3. cellular respiration aerobic components (Krebs & e- transport chain) isotonic - ANSWERStension is constant while muscle length changes isometric - ANSWERSmuscle contracts but does not change length - ie: holding book out origin - ANSWERSstationary insertion - ANSWERSmoving sarcomere - ANSWERScontractile unit of a muscle fiber