. Physiology, experimental and descriptive . Isolated Fibers Fibers Joined Fig. 24. Plain (Unstriated) Mus-cular Fibers from the Bladder. ACTION OF SHALL ARTERIES. 77 This is regulated by the medium-sized arteries leading tothe parts. In the walls of the small and medium-sized arte-ries are muscle fibers of a different kind from those of theskeleton. These fibers are spindle-shaped, as shown in Fig. 24,and do not have the cross-markings of the fibers of the skele-tal muscles; they are in consequence called Non-striated, Smooth Connective Tissue Endothelium. Muscle Fiber Fig. 25. Plain Muscle F
. Physiology, experimental and descriptive . Isolated Fibers Fibers Joined Fig. 24. Plain (Unstriated) Mus-cular Fibers from the Bladder. ACTION OF SHALL ARTERIES. 77 This is regulated by the medium-sized arteries leading tothe parts. In the walls of the small and medium-sized arte-ries are muscle fibers of a different kind from those of theskeleton. These fibers are spindle-shaped, as shown in Fig. 24,and do not have the cross-markings of the fibers of the skele-tal muscles; they are in consequence called Non-striated, Smooth Connective Tissue Endothelium. Muscle Fiber Fig. 25. Plain Muscle Fiber. Isolated and in wail of Artery. or Plain Muscle Fibers. They are arranged circularly in thewalls of the arteries. These fibers have, in common with allmuscle fibers, the power of shortening, but at a much slowerrate than the striated fibers. When they shorten they reducethe size of the artery, and, therefore, for the time, less bloodcan flow through the artery. When the muscle fibers cease toshorten, the artery widens, and allows more blood to passthrough it. To illustrate the action of the muscles in the walls of anartery, let the water run through a hose-or large rubber , if a row of persons take hold of this tube, the grip oftheir hands is like that of the muscles. When the hands 78 STRUCTURE OF ARTERIES. Endothelium Internal ElasticLayer Circular Mus-cle Fibers tighten their grip, the caliber of the hose or tube is dimin-ished, and less water is allowed to flow through it. When thehands relax, the tube, being elastic, allows more l
Size: 1787px × 1398px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauth, bookcentury1800, bookdecade1890, bookidcu31924031272762
