EXERCISES, LESSON 4
REQUIREMENT. The following exercises are to be answered by completing the
incomplete statements. After you have completed all the exercises, turn to "Solutions to
Exercises" at the end of the lesson, and check your answers.
s (holds up) the body.
Joints and attached skeletal muscles enable the parts of the body to move with
respect to each other; this is called
n. Such linkages in the lower members make
The skeleton helps to p
t vital organs.
The skeleton is involved in the formation of
The skeleton also stores various
Each bone is built upon a framework of
. Upon this framework,
crystals are deposited in regular order. When compressed, these crystals produce a
t. This phenomenon is called the
electric effect. Bones
tend to lose mass when they are not subjected to at least ordinary
The living cells of the bones are osteo
. When these cells are building up
bone tissue, they are called osteo
. When they are tearing down bone tissue, they
are called osteo
. The building and rebuilding respond directly to the directions of
applied to the body.
The envelope surrounding the "typical" long bone is the p
m. Adjacent to
the surface of the bone, there is a special layer of bone-forming cells called the
c layer. When a long bone is fractured without loss of the periosteum, the
fracture is healed by the combined action of the
c layer of the periosteum and
s of the bone itself.
In the early years of life, near each end of the long bones, there is a plate of
cartilage called the epi
plate. Between puberty and adulthood, this cartilage
is replaced by
development. The dense bony line remaining is called the