Physiology and Hygiene for Secondary Schools | Page 6

most important uses of
muscular tissue, osseous tissue, and connective tissue.
4. Define an organ. Define a system. Name examples of each.
5. Name the chief cavities of the body and the organs which they
contain.
6. What tissues are present in the hand? How does each of these aid in
the work of the hand?
7. Define an organization. Show that a railway system, an army, and a
school are organizations.
8. What is meant by the phrase "division of labor"? In what manner is
the division of labor practiced in a shoe or watch factory? What are the
advantages?
9. What are the proofs that the body is an organization?

PRACTICAL WORK
*Observation on the Tissues.*--Examine 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.*--Observe 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.

CHAPTER III
- THE BODY ORGANIZATION
What is the nature of the body organization? What are the individual
parts, or units, that make it up? What general work do these carry on
and upon what basis do they practice the division of labor? The
answers to these questions will suggest the main problems in the study
of the body.
[Fig. 3]
Fig. 3--Diagram showing the relation of the cells and the intercellular
material. C. Cells. I. Intercellular material.
*Complex Nature of the Tissues.*--To the unaided eye the tissues have
the appearance of simple structures. The microscope, however, shows
just the reverse to be true. When any one of the tissues is suitably

prepared and carefully examined with this instrument, at least two
classes of materials can be made out. One of these consists of minute
particles, called cells; the other is a substance lying between the cells,
known as the intercellular material (Fig. 3). The cells and the
intercellular material, though varying in their relative proportions, are
present in all the tissues.
*The Body a Cell Group.*--The biologist has found that the bodies of
all living things, plants as well as animals, consist either of single cells
or of groups of cells. The single cells live independently of one another,
but the cells that form groups are attached to, and are more or less
dependent upon, one another. In the first condition are found the very
lowest forms of life. In the second, life reaches its greatest development.
The body of man, which represents the highest type of life, is
recognized as a group of cells. In this group each cell is usually
separate and distinct from the others, but is attached to them, and is
held in place by the intercellular material.
*Protoplasm, the Cell Substance.*--The cell is properly regarded as an
organized bit of a peculiar material, called protoplasm. This is a
semi-liquid and somewhat granular substance which resembles in
appearance the white of a raw egg. Its true nature and composition are
unknown, because any attempt to analyze it kills it, and dead
protoplasm is essentially different from living protoplasm. It is known,
however, to be a highly complex substance and to undergo chemical
change readily. It appears to be the only kind of matter with which life
is ever