Quiz 1 Flashcards
Structural Breakdown of Muscle
muscle is made of fasculi, which are made of myofibers (muscle cells), which are made of myofibrils (sub-cellular contractile units)
Components of a myofiber
Sarcoplasmic reticulum, transverse tubules, plasmalemma, terminal cistern,actin and myosin fibers; many mitochondria
Sarcomere
Z-disk to Z-disk; composed of myosin and actin; shortens until the light band almost disappears during contraction
Myofibril
Structural and functional unit of the skeletal muscle system; either actin or myosin
Isotropic Bands
light bands; basically where the actin strands are
Anisotropic Bands
dark bands; basically where the myosin strands are
Ratio of myosin to actin
1 myosin for every 6 actin;
Connective Tissue in Muscle
endomysium (wraps every myofiber), perimysium (wraps every fascicle), and epimysium (wraps every muscle); gives toughness to transmit force that muscle tissue produces
Myoneural Junction
where nerve meets muscle fiber; creates a motor unit
Nerve Supply to Muscle
nerve/NT gets into sarcolemma and causes a wave of depolarization; T-tubules allow for nervous system to get down into the muscle cell quickly
First Half of Muscle Cell Depolarization
alpha motor neuron sends nerve signal which is carried across mho-neural junction via acetylcholine; causes depolarization in the sarcolemma, which reaches deep into the muscle via T-Tubules; causes calcium to be released from sarcoplasmic reticulum
Second Half of Muscle Contraction
calcium hooks up with troponin, causing a conformational change in tropomyosin, which normally covers actin’s binding site for myosin
Tropomyosin
normally covers actin’s binding site for myosin, so prohibits contraction until an action potential is spread
Troponin
causes a conformational change in tropomyosin so actin and myosin can bind; only is activated when calcium is released
ATP’s Action in Muscle Contraction
on the myosin head ATP exists along with myosin ATPase, which allows for ATP to be broken down quickly which is needed in order for actin and myosin to bind and to unbind
Sliding Filament Theory
rest, excitation-coupling, contraction, recharging, relaxation
Phospho-Creatine System
the first source of ATP; creatine kinase breaks down phosphocreatine to release energy and phosphate, which is then used to rebuild ATP; anaerobic; 3-15sec;
Glycolytic System
requires 2 ATP, creates 4 ATP; net gain of 2; produces pyruvic acid and lactic acid which prevents more time being spent using this system; also produces 2 NADH;
Oxidative System
pyruvic acid, instead of becoming lactic acid, loses a CO2 and enters the mitochondria as acetyl coA; consists of the Krebs cycle and the ETC; 32 ATP total
Rule for which system is used
intensity dictates duration
Krebs cycle
the main purpose is to package and transport H+ for the ETC; only produces 2 ATP (one for each acetyl coA) and 10 NADH and 2 FADH;
Electron Transport System
oxygen accepts H+ at the end of the ETC to produce water; FADH and NADH bring H+ to be accepted in the ETC; the splitting apart of FADH and NADH creates enough energy to put ATP back together again; 2.5 ATP for every NAD and 1.5 ATP for every FAD
Aerobic Lipolysis
triglycerides broken down to allow free fatty acids to be released into the blood and then enters the mitochondria;
ß Oxidation
takes the FFA and chops it into 2 carbon pieces and sends them to the Krebs cycle; with each cycle one NAD and FAD pick up H+ as well;
ATP Calculation for ß Oxidation
for every chop (C-1) multiply by 4 ATP; for every acetyl choline multiply by 10 ATP (C); add these together and subtract 2 for this is the requirement to begin oxidation
