There are three types of muscle tissue: Visceral, cardiac, and skeletal.
The total amount of muscle proteins in mammals, including humans, exceeds that of any other protein. About 40 percent of the body weight of a healthy human adult weighing about 70 kilograms pounds is muscle, which is composed of about 20 percent… General features of muscle and movement Muscle powers the movements of multicellular animals and maintains posture.
Its gross appearance is familiar as meat or as the flesh of fish. Muscle is the most plentiful tissue in many animals; for example, it makes up 50 to 60 percent of the body mass in many fishes and 40 to 50 percent in antelopes.
Some muscles are under conscious control and are called voluntary muscles. Other muscles, called involuntary muscles, are not consciously controlled by the organism. For example, in vertebrates, muscles in the walls of the heart contract rhythmically, pumping blood around the body; muscles in the walls of the intestines move food along by peristalsis; and muscles in the walls of small blood vessels constrict or relax, controlling the flow of blood to different parts of the body.
The effects of muscle changes in the blood vessels are apparent in blushing and paling due to increased or decreased blood flow, respectively, to the skin. Created and produced by QA International. Many protists unicellular organisms move instead by using cilia or flagella actively beating processes of the cell surface that propel the organism through water.
Some unicellular organisms are capable of amoeboid movement, in which the cell contents flow into extensions, called pseudopodiafrom the cell body. Some of the ciliated protozoans move by means of rods called myonemes, which are capable of shortening rapidly. Nonmuscular methods of movement are important for multicellular animals as well.
Many microscopic animals swim by means of beating cilia. Some small mollusks and flatworms crawl using cilia on the underside of the body. Some invertebrates that feed by filtering particles from water use cilia to create the necessary water currents. In higher animals, white blood cells use amoeboid movements, and cilia from cells lining the respiratory tract remove foreign particles from the delicate membranes.
Muscles consist of long slender cells fibreseach of which is a bundle of finer fibrils Figure 1. Within each fibril are relatively thick filaments of the protein myosin and thin ones of actin and other proteins. When a muscle fibre lengthens or shortens, the filaments remain essentially constant in length but slide past each other as shown in Figure 2.
Tension in active muscles is produced by cross bridges i. As the active muscle lengthens or shortens and the filaments slide past each other, the cross bridges repeatedly detach and reattach in new positions. Their action is similar to pulling in a rope hand over hand.
Some muscle fibres are several centimetres long, but most other cells are only a fraction of a millimetre long. Because these long fibres cannot be served adequately by a single nucleus, numerous nuclei are distributed along their length.
The arrangement of the myofilaments in a striated muscle. The muscle is extended in the upper diagram and contracted in the lower one. The thick filaments are 1. The work done by muscle requires chemical energy derived from the metabolism of food.
When muscles shorten while exerting tension and performing mechanical work, some of the chemical energy is converted to work and some is lost as heat.
When muscles lengthen while exerting tension such as in slowly lowering a weightthe chemical energy that is used, along with the mechanical energy absorbed by the action, is converted to heat.
Generation of heat is an important function of muscle in warm-blooded animals.Muscle: Muscle, contractile tissue found in animals, the function of which is to produce motion.
Movement, the intricate cooperation of muscle and nerve fibres, is the means by which an organism interacts with its environment. The innervation of muscle . Unlike Skeletal and Cardiac muscle tissue, Smooth muscle is not striated. Smooth muscle fibers are small and tapered - with the ends reducing in size, in contrast to the cylindrical shape of skeletal muscle.
Skeletal muscle cells are covered by connective tissue, which protects and supports muscle fiber bundles. Blood vessels and nerves run through the connective tissue supplying muscle cells with oxygen and nerve impulses that allow for muscle contraction.
Nov 21, · Subtype of the rhabdomyosarcoma (RMS) soft tissue cancer family whose lineage derives from the undifferentiated mesoderm Embryonal rhabdomyosarcoma (ERMS) is . 1. Introduction. Previously, we demonstrated that maternal low-protein or high-fat diets epigenetically regulate offspring adiposity, insulin resistance, and adipose and skeletal muscle oxidative functions,,,.Work by other groups has shown that both maternal and paternal diets and obesity affect offspring obesity risk and that the combination of maternal plus paternal obesity has an.
Go to the previous, next chapter.. Physiology of Stretching. Flexibility: (next chapter) ; Introduction: (previous chapter). The purpose of this chapter is to introduce you to some of the basic physiological concepts that come into play when a muscle is stretched.