position, called the ANATOMICAL POSITION,
is used as a point of reference. This anatomical
position is assumed when the body stands erect,
with arms hanging at the sides, and palms of the
hands turned forward (fig. 3-2).
Other commonly used anatomical terms in-
clude the following:
Anterior or ventraltoward the front, or ven-
tral (pertaining to the belly; abdomen), side of the
Posterior or dorsaltoward the back, or dor-
sal, side of the body.
Medialnear or toward the midline of the
Lateralfarther away from the midline of the
Proximalnearer the point of origin or closer
to the body.
Distalaway from the point of origin or away
from the body.
Figure 3-2 .Anatomical position.
Superiorhigher than or above.
Cranialtoward the head.
Caudaltoward the lower end of the body.
Inferiorlower than or below.
Erectnormal standing position of the body.
Supinelying position of the body, face up.
Pronelying position of the body, face down.
Lateral recumbentlying position of the body
on either side.
PeripheralThe outward part or surface of
CHARACTERISTICS OF LIVING
All living things, animals and plants, are
ORGANISMS that undergo chemical processes
by which they sustain life and regenerate cells. The
difference between them is that animals have sen-
sations and the power of voluntary movement and
require oxygen and organic food. Plants require
only carbon dioxide and inorganic matter for food
and have neither voluntary movement nor special
In man, some of the characteristic functions
necessary for survival include digestion,
metabolism, and homeostasis. DIGESTION in-
volves the physical and chemical breakdown of
the food we eat into its simplest forms.
METABOLISM is the process of absorption,
storage, and use of these foods for body growth,
maintenance, and repair. FIOMEOSTASIS is the
bodys self-regulated control of its internal en-
vironment. It allows the organism to maintain a
state of constancy or equilibrium, in spite of vast
changes in the external environment.
The smallest unit of life, the cell, is the basic
structural unit of all living things and a functional
unit all by itself. It is composed of a viscid,
jellylike substance, called PROTOPLASM, upon
which depend all the vital functions of nutrition,
secretion, growth, circulation, reproduction, ex-
citability, and movement. As such, protoplasm
has been called the secret of life.
A typical cell is made up of the plasma mem-
brane, a nucleus, and the cytoplasm.
The PLASMA MEMBRANE is a selectively
permeable membrane surrounding the cell. In
addition to holding the cell together, the mem-
brane selectively controls the exchange of