CHAPTER XVI 

 MUSCULAR MOVEMENTS 



Amorphous contractile substance and ameboid movements Ciliary movements Movements 

 due to elasticity Elastic tissue Muscular movements Contraction of involuntary mus- 

 cular tissue Physiological anatomy of the voluntary muscular tissue Connective tissue 

 Bloodvessels and lymphatics Connection of the muscles with the tendons Chemical 

 composition of the muscles Physiological properties of the muscles Elasticity of mus- 

 cles Muscular tonicity Sensibility of the muscles Muscular contractility and excit- 

 ability Muscular contraction Changes in the form of fibres during contraction Rigor 

 mortis Passive organs of locomotion Physiological anatomy of the bones Lacunae 

 Canaliculi Bone-cells or corpuscles Marrow of the bones Periosteum Physiologi- 

 cal anatomy of cartilage Cartilage-cavities Cartilage-cells Elastic cartilage and tibro- 

 cartilage. 



THE processes connected with the nutrition of animals involve cer- 

 tain movements ; and almost all animals possess in addition the power 

 of locomotion. Many of these movements have of necessity been con- 

 sidered in connection with the different functions ; as the action of the 

 heart and vessels in the circulation, the uses of the muscles in respira- 

 tion, the muscular acts in deglutition, the peristaltic movements and the 

 mechanism of defecation and urination. There remain, however, certain 

 general facts in regard to various kinds of movement and the mode of 

 action of the different kinds of muscular tissue, that demand more or 

 less extended consideration. 



Amorphous Contractile Substance and Ameboid Movements. In 

 some of the lowest forms of beings, in which hardly anything but 

 amorphous matter and a few granules can be recognized with the 

 microscope, certain movements of elongation and retraction of amor- 

 phous substance have been observed. In the higher animals, similar 

 movements have been noted in certain of their structures, such as the 

 leucocytes, the contents of the ovum, epithelial cells and connective- 

 tissue cells. These movements usually are simple changes in the form 

 of the cell; and they depend on an organic substance formerly called 

 sarcode and now known as protoplasm, which has already been described. 

 In the anatomical elements of adult animals of the higher classes, these 

 movements usually appear slow and gradual, even when viewed with 

 high magnifying powers ; but in some of the very lowest forms of life, 

 the movements serve as a means of progression and are more rapid. 



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