PSL300H1 Lecture Notes - Lecture 35: Endoplasmic Reticulum, Neuromuscular Junction, Skeletal Muscle
Document Summary
3 types of muscle: skeletal muscle, smooth muscle, cardiac muscle. Activated by somatic nervous system: via motor neurons. Neuromuscular junction (nmj) the location where motor neuron synapses onto skeletal muscle: is a very specific environment. Striated contractile filaments: contains sarcoplasmic reticulum (sr), which contains ca2+ storage. 1 muscle runs the entire length b/w 2 tendons: is one long cell, but contains many nuclei, fused together. Very specialized structure: nucleus pushed to the side, mitochondria (amount depends on the type of muscle, cytoskeletal repeats (myocin repeats) Sarcoplasmic reticulum (sr): specialized type of er to contain calcium, wraps around myofibrils, have terminal ends, that push against t-tubules, ca2+ stored at sites adjacent to t-tubules (space available for ca storage) T-tubules: connected to sarcolema, and dives into the individual muscle fibers: allows the ion messages to go into the individual muscle cells. 1 motor unit = 1 neuron & its specific muscle fiber.
