BIO 012 Lecture Notes - Lecture 16: Smooth Muscle Tissue, Skeletal Muscle, Troponin
Document Summary
Smooth muscle is made up of gap junctions held together by proteins called connexions. This allows for the owing of electrical potential (signaling) between cells. It is lined with blood vessels for base contraction and base-dilation to change the sizes of muscles. No troponin or tropomyosin conformational changes are required in smooth muscle cells as compared to skeletal muscle cells. Calcium enters smooth muscle cells through three different possible receptors: mechanoreceptors, ligand receptors, or voltage-gated receptors. One calcium is within a smooth muscle cell, it causes the activation of calcium calmodulin kinase, an enzyme that breaks atp into its respective adp + pi formation. Calcium entering a smooth muscle cell starts a second messenger system. Action potentials cause minimal units of contraction within a motor unit. These minimal units of contraction that are the amounts of force generated from an action potential are called twitches.