. Elements of biology; a practical text-book correlating botany, zoology, and human physiology. Biology. MUSCLES 363. moves least is the origin. Muscles are named biceps or triceps (two-headed or three-headed, depending on the number of tendons found at the origin): the gastroc- nemius, already referred to, is a biceps muscle; the large muscle forming the front part of the thigh is a triceps muscle. Microscopic Structure of Vol- untary Muscle. — With a sharp pair of scissors cut through the belly of a muscle at right angles to the long axis ; examination will show that it is com- posed of a nu
. Elements of biology; a practical text-book correlating botany, zoology, and human physiology. Biology. MUSCLES 363. moves least is the origin. Muscles are named biceps or triceps (two-headed or three-headed, depending on the number of tendons found at the origin): the gastroc- nemius, already referred to, is a biceps muscle; the large muscle forming the front part of the thigh is a triceps muscle. Microscopic Structure of Vol- untary Muscle. — With a sharp pair of scissors cut through the belly of a muscle at right angles to the long axis ; examination will show that it is com- posed of a number of bundles of fibers. These fibers are held together by a sheath of connective tissue called the perimysium (Lat. = around the mus- cle). Each of these bundles may be separated into smaller ones. If we continue this so as to separate into the smallest possible bits that can be seen with the naked eye, and then examine such a tiny portion under the com- pound microscope, it will present some- what the appearance of the figure. The muscle is seen to be made up of a number of tiny threads which lie side by side, held together by the peri- mysium. Each thread consists of sev- eral muscle fibers, each of which is inclosed in a tiny sheath. A single fiber under the compound microscope appears to have alternate light and dark bands running at right angles to its long axis. This gives the bundle of fibers a striped appearance. Nuclei are seen here and there, showing that the muscle is made up of cells. Such is the structure of muscle fibers which are under the control of the will, the vol- untary muscles as they are called. If it were possible to prepare muscle fibers in such a manner as to trace the path of the nerves in these fibers, such nerves would be seen to end in little A bit of voluntary muscle fiber, showing the cross striations as seen under the Please note that these images are extracted from scanned page images that may have been digitally enhanced for
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