BIO210Y5 Lecture Notes - Lecture 5: Gross Anatomy, Epimysium, Perimysium
Document Summary
Cells are short, single nucleus, branched & striated, connected by intercalated discs, involuntary. Cells are short spindle shaped, not striated and one central nucleus. Ie; walls of blood vessels, lining of the digestive tract. : skeletal. Cells are long cylindrical, striated and multinucleate. Incapable of reproducing but myosatellites can reproduce for muscle repair. Perimysium: divides muscle into sections called fascicles. Myo laments are made of actin & myosin. Myosin head is tightly bound to actin active site. Cross-bridge is at 45 degrees in relation to the lament: myosin release. Atp is broken down to adp & phosphate. Energy is released and allows myosin head to move down the actin lament into a cocked position. Myosin head binds weakly to the actin active site. Binding happens 1-2 positions away from original. Myosin head remains still in cocked position: power stroke. This strengthens the bond between myosin and actin.