Skeletal muscle is the only voluntary muscle tissue in the human body-it is controlled consciously. These features also help to spread electrochemical signals quickly from cell to cell so that the heart can beat as a unit. The branched structure and intercalated disks allow the muscle cells to resist high blood pressures and the strain of pumping blood throughout a lifetime. Intercalated disks are made up of fingerlike projections from two neighboring cells that interlock and provide a strong bond between the cells. The cells of cardiac muscle are branched X or Y shaped cells tightly connected together by special junctions called intercalated disks. Striations indicate that a muscle cell is very strong, unlike visceral muscles. The arrangement of protein fibers inside of the cells causes these light and dark bands. The cells of cardiac muscle tissue are striated-that is, they appear to have light and dark stripes when viewed under a light microscope. Because of its self-stimulation, cardiac muscle is considered to be autorhythmic or intrinsically controlled. The natural pacemaker of the heart is made of cardiac muscle tissue that stimulates other cardiac muscle cells to contract. While hormones and signals from the brain adjust the rate of contraction, cardiac muscle stimulates itself to contract. Cardiac muscle tissue cannot be controlled consciously, so it is an involuntary muscle. Cardiac Muscleįound only in the heart, cardiac muscle is responsible for pumping blood throughout the body. This smooth appearance starkly contrasts with the banded appearance of cardiac and skeletal muscles. The term “smooth muscle” is often used to describe visceral muscle because it has a very smooth, uniform appearance when viewed under a microscope. Because visceral muscle is controlled by the unconscious part of the brain, it is known as involuntary muscle-it cannot be directly controlled by the conscious mind. The weakest of all muscle tissues, visceral muscle makes organs contract to move substances through the organ. Visceral muscle is found inside of organs like the stomach, intestines, and blood vessels. There are three types of muscle tissue: Visceral, cardiac, and skeletal. In these organs, muscles serve to move substances throughout the body. Muscle tissue is also found inside of the heart, digestive organs, and blood vessels. Each of these muscles is a discrete organ constructed of skeletal muscle tissue, blood vessels, tendons, and nerves. Attached to the bones of the skeletal system are about 700 named muscles that make up roughly half of a person’s body weight. The muscular system is responsible for the movement of the human body. Flexor Digiti Minimi Brevis Muscle of Hand.
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