What is the microscopic anatomy of smooth muscle?
Smooth muscle, also called involuntary muscle, muscle that shows no cross stripes under microscopic magnification. It consists of narrow spindle-shaped cells with a single, centrally located nucleus. Smooth muscle tissue, unlike striated muscle, contracts slowly and automatically.
What are the histological features of smooth muscle?
Smooth muscle is made up of cells that contain a single central nucleus. The cells stick together and are connected by specialised cell junctions, called gap junctions. The cells are spindle shaped, and the nucleus is central.
What is the structure of a smooth muscle cell?
Smooth muscle consists of thick and thin filaments that are not arranged into sarcomeres giving it a non-striated pattern. On microscopic examination, it will appear homogenous. Smooth muscle cytoplasm contains a large amount of actin and myosin. Actin and myosin act as the main proteins involved in muscle contraction.
What is the gross anatomy of a muscle?
Gross anatomy Each muscle unit (fibers, fascicles and whole muscles) is surrounded by an extracellular matrix layer consisting of connective tissue of different strengths 2,3: endomysium: surrounds each muscle fiber. perimysium: surrounds the muscle fasciculi. epimysium: covers the whole muscle.
What is multi-unit smooth muscle?
Multi-unit smooth muscle, the second type of smooth muscle observed, are composed of cells that rarely possess gap junctions, and thus are not electrically coupled. As a result, contraction does not spread from one cell to the next, but is instead confined to the cell that was originally stimulated.
What is the smooth muscle cell?
Smooth muscle cells (SMCs) are involuntary, non-striated muscle cells that line the insides of hollow organs such as arteries, lungs, bladder, the digestive system, and the reproductive system.
What is the characteristics of smooth muscle?
Visceral muscles are also commonly known as smooth muscle due to their lack of striations. Four characteristics define smooth muscle tissue cells: they are involuntarily controlled, not striated, not branched, and singly nucleated.
What are the major histological differences between skeletal cardiac and smooth muscle?
Cardiac and skeletal muscle are both striated in appearance, while smooth muscle is not. Both cardiac and smooth muscle are involuntary while skeletal muscle is voluntary.
What is multi unit smooth muscle?
What are the characteristics of smooth muscle cells?
Smooth muscle cells are elastic, not striated, spindle-shaped and contain a single central nucleus. Smooth muscle cells are arranged together in sheets and this organisation means that they can contract simultaneously. However, they do contain other normal cell organelles such as sarcosomes but in lower numbers.
What is the gross and microscopic structure of striated muscle?
Sarcomeres are the basic unit of skeletal muscle, which are composed of muscle fibres (myocytes). Myocytes are composed of ‘myofibrils’ which are themselves made up of repeating sections of sarcomeres. Under microscopic observation it is these structures that can be visualised as both light and dark bands.
What is the microscopic structure of a muscle?
A sarcomere is the basic unit of muscle tissue in both cardiac and skeletal muscle. Sarcomeres appear under the microscope as striations, with alternating dark and light bands.
1 Structure. The smooth muscle cell is 3-10 µm thick and 20-200 µm long. The cytoplasm is homogeneously eosinophilic and consists mainly of myofilaments. 2 Function. Smooth musculature is found in (almost) all organ system such as hollow organs (e.g. 3 Innervation. The innervation of the smooth musculature is utmost complex.
Why does smooth muscle appear non striated under light microscopy?
Under light microscopy, skeletal and cardiac muscles appear striated due to the parallel arrangement of their contractile filaments into repeating units called sarcomeres. Smooth muscle tissue appears non-striated because of the less orderly arrangement of their filaments.
Where are smooth muscles found in the intestine?
In the histology of hollow organs like the esophagus, intestine, you will find two concentric layers of smooth muscles in the same section of that particular tissue. You will find inner circular and outer longitudinal layers of smooth muscles in the esophagus, large intestine and small intestine of animals.
What do myofibroblasts do in the smooth muscle?
Myofibroblasts represent a special type of smooth muscle cell which additionally have qualities of fibrocytes. They produce connective tissue proteins such as collagen and elastin for which reason they are also referred to as fixed (or stationary) connective tissue cells.