KINE 1020 Lecture Notes - Lecture 44: Endoplasmic Reticulum, Myosin Head, Sarcomere
1 Feb 2018
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Actin and myosin are stabilized to end point = z disk. Able to interact cause myosin connected to black line. A band darkest colour, actin and myosin overlap here. H= myosin only a= myosin and actin overlap i= actin only titin stabilizing sarcomere when you contract a fibre,actin becomes shorter. When you contract myosin doesn"t become short it only twitches. A band is the overlap of myosin and actin. Eccentric contractions are when you put something down slowly ( contracting but lengthening) ex. squats. Sliding filament theory( myosin doesn"t contracts, heads twitch, and acti does not contract as well) Sarcomere-proteins: actin : g-actin monomers, f-actin filaments, myosin-binding site blocked by tropomyosin, troponin (3 units) moves tropomyosin when ca2+ present, myosin : head and tail regions contains binding sites for actin and atp, actin-myosin interaction: contraction through sliding filament. An -motor neuron connects and innervates muscle fibres. Contraction is triggered by an action potential (from the brain/spinal cord to -mn)
