Muscle Cells Research Paper

Anatomy of Muscle Cells There are three types of muscle tissue in the human body. These muscle tissues are skeletal muscles, smooth muscles and cardiac muscles. Each of these muscle tissues has it very own anatomical makeup, which vary from muscle to muscle. The muscle cells in a muscle are referred to as muscle fibers, these fibers are skeletal muscle fibers, smooth muscle fibers and cardiac muscle fibers. The anatomy of a skeletal muscle fiber is formed during embryonic development. Skeletal muscle fibers arise from a hundred or more small mesodermal cells called myoblasts. The mature skeletal muscle fiber has a hundred or more nuclei. Once fusion occurs the skeletal muscle fiber will lose the ability to undergo cell division.
Thousands of invaginations of the sarcolemma, which are called T Tubules, Tunnel from the surface to the center of the muscle fiber. These T Tubules are open to the outside of the fiber and are filled with extra-cellular fluid. Muscle action potentials propagate along the sarcolemma and through the T tubules and quickly spread through the muscle fiber. This process ensures that all parts of the muscle fiber become excited by an action potential virtually simultaneously. The sarcoplasm is located inside the sarcolemma. Sarcoplasm is the cytoplasm of a muscle fiber, it contains a good amount of glycogen, which is used for ATP synthesis. The sarcoplasm also contains myoglobin, a red colored, oxygen binding-protein, that is found only in muscle fibers. The myoglobin binds oxygen molecules, which are needed for ATP production within the mitochondria. The Mitochondria lie in rows throughout the muscle fiber, strategically close to the proteins that use ATP during
Jain The sarcoplasmic reticulum is a fluid filled system of membranous sacs. This system of sacs is similar to smooth endplasmic reticulum in non-muscle cells. In a relaxed muscle fiber the sarcoplasmic reticulum store calcium ions, the release of these calcium cells, trigger muscle contraction. There are two types of structures which are even smaller, they are known as thick and thin filaments. The filaments inside of a myofibril do not extend the entire length of a muscle cell, instead they are arranged in compartments called sarcomeres. The darker middle portion of a sarcomere is called the A-band. The A-band extends the entire length of the thick filaments. The A-band is a zone of overlap. The I-band is a lighter less dense area that contains the rest of the thin filaments, but has no thick filaments. A Z-disk passes through the center of each I band. The next form of muscle fiber is smooth muscle fiber, these fibers are considerably smaller than skeletal muscle fibers. A single smooth muscle fiber is thirty to two hundred micrometers long, thick centered and tapered at the ends. These smooth muscle fibers have a single nucleus that is centrally located and oval in shape. Smooth muscle fiber contains thick filaments and thin filaments. These filaments are in ratios of 1:10 and 1:15, but are not arranged in order sarcomeres as in striated