KINE 1020 Lecture Notes - Lecture 3: The Sequence, Titin, Myocyte

• School: York University
• Department: Kinesiology & Health Science
• Course: KINE 1020
• Professor: Michael Riddell

Document Summary

Electrical signals are charged substances positive or negative i. e na & k. A(cid:272)tio(cid:374) pote(cid:374)tial is (cid:449)he(cid:374) na (cid:272)o(cid:373)es i(cid:374) a(cid:374)d k goes out; the(cid:396)e(cid:859)s a difference in electrical charge in membrane; one side becomes more positive and the other less positive ; uses atp. Goes all the way down to the nerve to the muscle. Acetylcholine (a neurotransmitter) is released, helps action potential jump from the nerve to the muscle, fuse w the membrane through a voltage activated mechanism. Another action potential is triggered which is propagated along the sarcolemma and down the t tubules. Action potential in t tubule activates voltage-sensitive receptors, which in turn trigger ca 2+ release from terminal cisternae of sr into cytosol. Calcium ions bind to troponin (proteins that sit on top of myosin); troponin changes shape, removing the blocking action of tropomyosin (blocks active sites of actin); actin active sites exposed reason why we can relax.