Examples of involuntary muscles, also known as smooth muscles, are the muscles of the urogenital tract, digestive tract, circulatory system and respiratory tract. Involuntary muscles are not controlled by the organism's will. Their actions are automatic and facilitated by the autonomic nervous system.Continue Reading
The structure of an involuntary muscle cell consists of a long, spindle-shaped cell without striations. The cells may occur as individual cells, in groups or as sheets. Contractions occur either in slow, spontaneous rhythms or as sustained contractions for longer durations.
The involuntary muscle is one of three types of muscles found. The other two types are skeletal and cardiac. Skeletal muscle is a type of voluntary muscle, meaning it is controlled by the organism's will. The skeletal muscle is also referred to as a striated muscle because of the alternating muscle fibers that are light and dark colored. Present in these fibers are specialized protein filaments that are responsible for the contraction of the muscle.
Skeletal muscles are attached to bones of the body through tendons. When skeletal muscles are discussed in combination with the bones of the body, the combined system is called the musculoskeletal system. Over 600 muscles are present in the entire human body.Learn more about Muscles
The Clermont College Biology Department lists examples of flexor muscles as the biceps brachii and the hamstrings, and some examples of extensor muscles are the triceps brachii, the quadriceps femoris and the gastrocnemius. One of the most well-known extensor muscles is the Achilles tendon.Full Answer >
The stomach contains three layers of smooth muscle that allow it to contract to mix and propel food though the digestive tract. Contained in the muscularis layer of the stomach, the three layers of smooth muscle fibers run in three different directions. These three layers of smooth muscle are required because smooth muscle can contract only in one direction.Full Answer >
Paraspinal muscles are located next to the spine and are responsible for motor movement of the spinal column, according to the University of Maryland Medical Center. Paraspinal muscles coordinate movement of the spine with the rest of the skeleton. When the spine is injured, paraspinal muscles spasm to prevent movement of the injured area, thereby reducing chances of further injury.Full Answer >
Accessory muscles, as medically defined, are duplicates of a muscle in the human body. However, accessory often refers to the muscles not usually or not directly involved in performing a task or doing physical work.Full Answer >