Physiology and Hygiene for Secondary Schools by Francis M. Walters;A.M.
page 17 of 527 (03%)
page 17 of 527 (03%)
|
*Observation on the Tissues.*âExamine with care the structures in the entire leg of a chicken, squirrel, rabbit, or other small animal used for food. Observe, first of all, the external covering, consisting of cuticle and hair, claws, scales, or feathers, according to the specimen. These are similar in structure, and they form the epidermis, which is one kind of _epithelial_ tissue. With a sharp knife lay open the skin and observe that it is attached to the parts underneath by thin, but tough, threads and sheaths. These represent a variety of _connective_ tissue. The reddish material which forms the greater portion of the specimen is a variety of _muscular_ tissue, and its divisions are called muscles. With a blunt instrument, separate the muscles, by tearing apart the connective tissue binding them together, and find the glistening white strips of connective tissue (tendons) which attach them to the bones. Find near the central part of the leg a soft, white cord (a nerve) which represents one variety of _nervous_ tissue. The bones, which may now be examined, form the _osseous_ tissue. At the ends of the bones will be found a layer of smooth, white material which represents one kind of _cartilaginous_ tissue. The _adipose_, or fatty, tissue, which is found under the skin and between the other tissues, is easily recognized. *Relation of the Tissues to the Organs.*âObserve in the specimen just studied the relation of the different tissues to the organ as a whole (regarding the leg as an organ), _i.e._, show how each of the tissues aids in the work which the organ accomplishes. Show in particular how the muscles supply the foot with motion, by tracing out the tendons that connect them with the toes. Pull on the different tendons, noting the effect upon the different parts of the foot. |
|