BSCI 201 Lecture Notes - Lecture 27: Arrector Pili Muscle, Smooth Muscle Tissue, Cardiac Muscle
15 Nov 2016
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Document Summary
Single unit smooth muscle: smooth muscle cells are connected by gap junctions, pacemaker activity which is intrinsic to the smooth muscle is present, contracts as a single unit contraction occurs in all the smooth muscle cells simultaneously. Multiunit smooth muscle: gap junctions are absent in multiunit smooth muscle, smooth muscle cells contract independent of other smooth muscle cells in the smooth muscle. Multiunit smooth muscle the contraction can be graded depending on how many smooth muscle cells are activated to contract arrector pili muscle. Cardiac muscle is referred to as a blended muscles. So it possesses characteristics similar to skeletal muscle and similar to single unit smooth muscle. Contains cardiac muscle tissue with connective tissue wrapping. Uninuleated, which is similar to smooth muscle cell. Hence, tropomyosin blocks the myosin binding sites on actin in a relaxed cardiac muscle. Cardiac muscle is innervated by the autonomic nervous system, similar to smooth muscle.
