The Structure and Function of Muscle

The Structure of function of muscle The skeletal muscle consist of differens protein tees major protein that involver in muscle contraction are actin & myocin The protein associated with Thin filar. fila Troponin It is present in thin filarment helps in bind with myocin Tropomyocin It helps in maintaining of the stability of thin filament Nebulin maintains the length of thin filament & present throughout the length of thin filament. Dystrophin→ It is a ling-frotein that helps of attachment of sancomere to Sancolemma Mysein protein It is a Preletal muscle major protein found in having parts lixe head body of fail st. of one myocin filament, Tail Body Head myecin 1 myocia On one of almost 500 nyocin filament comp 500 myocin molecules Each molecule has the myocin head part, jeinted by a body s a double helical tail. Thi myocin had puoject outside to form Cross bridges Actin filament point Actin filament constict of proteine live Actin, Tropolins. etc. It can be forms Occur in probular form Tropamyoun tues different and ar (4-form) felamental form (F-Form). The G-Ferm poly- merises to form (f-form). Treopomycin is a double Stranded helical structure which present in actin awhile the tropenin consist of 5-probular molecules that Contain Calcium son binding site. Jo bive The tropanem & calcium ton helps to formation of crossbridge betareen actin & myocin 0006-actin polymercises Preocess of Muscle Contraction Molecular basis of muscle. Contraction Sliding filament Theory (s.Norm) 700003) Tues different pncups of scientist H.E Hauxley & Hanson in 1954 and Af Hexley & &-Nederperre explained the Slidinis felament theory of Contractim. muscle According to this theory. + During muscle. Contraction the length of Actio & myocin felament remain constant Durcing contrcation the length of ArBand remain constant uwhile the length of +1-201 and I-Band will finally discapear. decreases & → The z line -finally touch the end of nyocin peranants qu → when the Actin filament slide over the thick myocin filament, the H-zone betercer the end of the actinfilament gradually dissapear and the end of thin filament the centre of farcomere notein which has taro Clay The myocin protein the my aves ft. The myosia-I contam simple head while the gmyosin- contain tues myosin heads. This mean fer the actin filament. myosin attachment heads ar of myocin to Process:- The Greletal muscles are bene by tendon compared of attached to bene connective tissue. This skeletal musele constitute bundles of vescicles. hehen 400 looked into myofibril contai the thin and thick filament criented in Such a manger the thick filament will. Slide over the thin а вансотене. filament. It constitute The thick myosin filament consist of different myosin molecule. when myosin is acted upon by trypsin it poves mise a light chain called light memomysin and heavy chain called heavy meremytin →Among this teces fragment the light mersing contain ATPase activity. ushich is not combine weith actin ore thin filament while heavy freapment is meant for heptnolysis of ATP and binds to Actin and Myerin Myosin-1 kremotif Myosin-3 Imyptia frapment Light mercomyosin ATPase activity not combined with actin breaves of Heavy meremyosin Hydrolysis of APP (APP APP:P) Binds to actin Be The thin filament constitute & major preoteens ce Acten, tropmyocin of Troponin The tropome Tropomycin is a a fibrous fibrous molecule Constitute (3) Stropomycin (Tropomyosin be T bind (ii) Treepemystin I (Inhibitory subunit) 1) Tuopn c. (cast con binding) you The Theoponin e dructurally I function 7 Sermilar to Calrnodulin having four binding bite for Calcium alium ion. The thin Actin filament formed by jumera placutar Subunits :... Cyprotein is together Constitute f-actin by polymerisation Sliding filament theory → The sliding of myocin head in thin filaments proposed by the trees proups of scientist are called sliding filament theary. Chemical Basis of Muscle. Contraction 7 The signal that come from the Jeuriог trippers the action potention in the sarecolemmi Thee action potential travels through the T-tubule or transversed tubule. which is the inwared extention in the sarcolemma 7 The T tubale Contains Voltage Sensitiv proteins which is activated by action potential. This activated voltage sensitiv proteins trippers the calcium ion changa Puikant in the Bare coplasmic reticulum. →This increased Conce Concerntration of Ca in the Sarcoplasmic reticulum enhance t muscle Contraction. Steps involved in Contraction The nerve treassmestion genereates the action of potential on muscle febre Release of Calcium ion from earccoplasmic Meticulum which was Stoned oluring contracom The binding of Ca con to treopomycin C The 0 Lingage Location selding myocin by selding by thich filament ↓ bet actin thin filament over bart piszem Couplings of Actinif myaric & ATP hydrolysis The binding of ATP to myocin - II changes. the actin binding site. This reduces the head of myosin- for actic folament of allows it to move along the fetament Hydrolysis of ATP causes the mgocin head to be displaced along the Ana filament while the product of ATP. hydrolysis ire ADP & Pi are to myown head. still attached In next Step the Pi is being relleane and the myocin head with ADP bound bind a different site in the Actin filament. This trippers the App and start o myocin head to leave The muscle Contraction is process when the muscles. an active i's Stimulated the Sarcoplasmic Reticulum şives calcium ion and When the muscle start to relax the calciurn ion returns back to Sarcoplasmic reticulum During this process the muscle glycogen broken douen into lactic acid of reelease some amocent of ATP & in some cases the lactic acids further Uberates some enerepy, co and Hㅇ is described by Cori Cyck ร This (Skeletal) (Muscle)