The cytoskeleton provides support in a cell. It is a network of protein fibers supporting cell shape and anchoring organelles within the cell. The three main structural components of the cytoskeleton are microtubules (formed by tubulins) , microfilaments (formed be actins) and intermediate filaments.
epinephrine binds to beta 2 receptors to relax airway smooth muscle and relaxes larger arteries to supply more blood to metabolizing tissues What is theophylline? an inhibitor of phosphodiesterase so it will potentiate the effect of epinephrine and inhibit cAMP breakdown to relax smooth muscle
1 Steroids pass into a cell's nucleus, bind to specific receptors and genes and trigger the cell to make proteins. 2  Amino acid derivatives, such as epinephrine, are water-soluble molecules derived from amino acids (the building blocks of protein). 3  These hormones are stored in endocrine cells until needed.