Skeletal Muscle

Question 1

• Muscle breakdown? (6)
• Muscle cell? Collection of myoflaments? Actin/myosin?
• Intercalated discs/ gap junctions?
• No striations/1 nucleus?
• Thick filament? Structure? Thin filament? Binds Ca? Binding sites? Blocks binding of myosin?
• Steps in a power stroke? (5)
• Resting sarcomere length? Breaking point?

Answer 1

• Muscle –> Fassicle –> Myofiber –> Myofibril –> myofilaments –> Sarcomere
• Myofiber; myofibril; myofilaments
• Cardiac muscle
• Smooth muscle
• Myosin (2 heads, hinge, 2 coiled a helices), actin; troponin; tropomyosin
  1. ) ATP binds and releases head 2.) Hydrolysis to ADP + P cocks head 3.) Myosin binds 4.) Power stroke, P released 5.) ADP released, ATP binds
• 2.4 Um; >3.6 Um

Question 2

• Contraction of smooth muscle controlled by? Have to burn atp?
• Spinal motor neuron events? (6)
• Two calcium channels? Which membrane embedded? Direct contact of the two where? Calcium induced calcium release where? Calcium then?
• Single motor unit?
• Increase tension in skeletal muscle via? (2) cardiac? (3)
• Repair in skeletal muscle? cardiac? smooth?

Answer 2

• Phophorylation of myosin light chain; no
• ACH release –> Binds AchR –> Depolarize cell –> T tubules depolarize –> calcium released in SR –> Pumped back in via Ca-ATPase pump
• DHPR (t membrane voltage gated); RyR SR membrane ca channel; Skeletal; cardiac; actively pumped back into SR
• Neuron + all muscle fibers it innervates
• AR frequency and motor unit recruitment; hormones, NT, length tension
• Sattelite; none; cell division