i6 



PR A CTICAL ANA TOM \ '. 



cornea, peristructures, supporting structures, dentine, and Wharton's jelly, you 

 are to remember, these structures, while widely varying in form, all belong to 

 the greater connective tissue family. 



RESUME OF ANATOMICAL TISSUES. 



1. Muscular tissue, for voluntary and involuntary contraction, upon which 



depend the aggressive and defensive attitudes of the body, as well as 

 the movements of hollow conduits and certain viscera. 



2. Nervous tissue, upon which depends intellection, reception of impression from 



an environment, and transmission of brain impulses, whether voluntary 

 or involuntary. 



3. Connective tissue, on which depends strength, framework, and various invest- 



ing structures. Common forms specialized are tendon, ligament, capsule, 

 bone, cartilage, dentine, cementum, etc. 



4. Epithelial tissue, upon which depend external and internal protection, giving 



as these tissues do a certain resiliency and stability to the areas which 

 they cover, as the skin and mucous membranes. 



/$W ofcompressed 

 cotfon reareseafint 



sheath. 



Nerve 



Artery 



Vein 



FIG. i. DISPLACEMENT OF COTTON BY GROW- 

 ING PLANTS. 



Meuro venous septum 

 Neuro arterial septum- . 



FIG. 2. CONNECTIVE TISSUE DISPLACED BY 

 THE ARTERY, NERVE, AND VEIN; THE 

 CONNECTIVE TISSUE LEFT BETWEEN THE 

 ARTERY AND NERVE AND BETWEEN THE 

 NERVE AND VEIN ARE Two SEPTA. 



Rationale of the formation of anatomical sheaths, tunics, togas, cap- 

 sules, and all the peristructures referred to and enumerated in the section on 

 anatomical nomenclature. 



In your dissections you will meet the capsules of glands and the sheaths of 

 vessels. Where an artery, vein, and nerve are in the same sheath, they will be 

 separated from each other by a. septum. In your first dissection you will be dis- 

 appointed at the frail condition of these sheaths at their lack of organization. 

 You will expect to find the sheath of an artery resemble a piece of heavy cloth 

 sewed tightly about the trunk of a tree ; your chagrin will be manifest when 

 you find it resembles more the investment of straw given tender shrubs to pre- 

 vent depredations of rodents in our parks. As any attempt to remove the pro- 

 tective from the tree would result in the complete destruction of the protective, as 

 you removed straw after straw, so, likewise, when you attempt to disen- 

 sheath a vessel you arrive at the vessel, but the sheath has disappeared. Re- 

 member, then, sheaths arc actual entities, and their architecture is adapted to the 

 needs and requirements of the vessel ensheathed, just as the cobweb is architect- 

 urally suited to the needs of the spider; still, when you molest the latter or 

 attempt to dissect the former, the result is the same each almost completely 

 disappears, such is the delicacy of their respective material. 



