Anatomy, Smooth Muscle

Excerpt

Smooth muscle is found throughout the body where it serves a variety of functions. It is in the stomach and intestines where it helps with digestion and nutrient collection. It is found throughout the urinary system where it functions to help rid the body of toxins and works in electrolyte balance. It is found throughout arteries and veins where it plays a vital role in the regulation of blood pressure and tissue oxygenation. Without these vital functions, the body would not be able to maintain the most basic functions.

Smooth muscle differs from skeletal muscle in a variety of ways, perhaps the most important being its ability to be contracted and controlled involuntarily. The nervous system can use smooth muscle to tightly regulate many of the body's subsystems for life with no thought from the user. A person does not need to think about their blood pressure for it to adapt to increasing oxygen demands from exercise. The nervous system instead uses hormones, neurotransmitters, and other receptors to control smooth muscle spontaneously.

Smooth muscle also plays an important role in the disease process throughout the body. The use of bronchodilators to relax airway smooth muscle is an important and life-saving treatment in asthmatics. Likewise, medications like metoclopramide can stimulate and promote gastric emptying by increasing smooth muscle signaling. Perhaps one of the most well-known uses of medical therapy and smooth muscle is the use of nitrates in the treatment of ischemic heart disease where nitrates, in combination with ACEI, can improve patient mortality. The singularly large impact that smooth muscle has throughout the body makes it an important topic for medical professionals to understand. As many treatments at their core rely on modifying the signaling pathways that affect smooth muscle.