LIFESCI 2 Lecture Notes - Lecture 16: Endoplasmic Reticulum, Ryanodine Receptor, Calcium In Biology

• School: UCLA
• Department: Life Sciences
• Course: LIFESCI 2
• Professor: Arnold, A.P., Esdin, J.

Document Summary

Musculoskeletal system: muscles are contractile tissues, classification. Voluntary muscles involuntary: muscle -> fascicle (bundle of muscle cells) -> muscle fiber/muscle cells -> myofibril (bundle of proteins) -> sarcomere (functional unit of muscle) In center, thick filaments; in peripheral, thin filaments, middle of sarcomere, overlapping. Filaments where force production occurs (physical interaction b/ thin & thick filaments) Filaments normally not physically touching, but in contraction, physical interaction. Myosin has binding sites on cross bridge for actin & atp. Myosin acts like enzyme atpase, atp broken to adp. 3 proteins: tropomyosin, troponin, actin actin is globular protein that polymerizes to form intertwined helix. Contractile like myosin tropomyosin & troponin are regulatory proteins, not contractile, so no force production tropomyosin. 3 binding sites: for ca2+, actin, tropomyosin: when muscle relaxed, thin & thick filaments overlap; when contract, sarcomere shortened, muscles are excitable, binding occurring. Ca2+ in neurons plays different role from in skeletal muscles. Ligand gated ion channels/ach receptors bind to ach.