The answers are as follows:
66) Cells that can dissolve the bony matrix are called OSTEOCLASTS.
Osteoclasts are very large motile cells which have multiple nucleus. They are formed from the fusion of bone marrow derived cells. Their principal function is to dissolve the bony matrix through the process called osteolysis. They also participates in regulation of calcium and phosphate concentrations in the body fluids.
67) Layers of calcification that are found in bone is called OSTEONS.
The basic unit of a compact bone is osteon. An osteon contains lamellae, osteocytes and a central canal and is found in compact bone only. The blood vessels and the nerve fibers are located in the central canal. The layers of calcification that are found in compact bone are also called lamellae.
68) Cells that can build bony matrix are called OSTEOBLASTS.
Osteoblasts are bone forming cells, they produce new bone matrix by the process of osteogenesis. Osteoblasts are located exclusively on the surface of the bone matrix where they function in matrix synthesis. The activities of the osteoblast are stimulated by the influence of parathyroid hormone.
69) Area where bone growth takes place is called EPIPHYSEAL PLATE.
The epiphyseal plate is a hyaline cartilage plate which is located on the surface of every long bone. It is the area of growth in a long bone.
70)
Wrist joint: is an example of PLANE JOINT.
Plane
joint is a type of joint in which bones slide along beside one another, thus
allowing for movement in many directions. This makes the body parts with plane
joints to be flexible. This type of joint is also called gliding joint.
71)
Shoulder joint: is an example of BALL AND SOCKET JOINT.
Ball
and socket joint is a type of joint in which the ball shaped surface of a
rounded bone is fitted into a depression of another bone. This type of joint
allows for movement of the bone around all axes. That is, the joint can rotate
in a full circle and move around its axis. Ball and socket joint is also found
in the hips.
72) Elbow joint: is an example of HINGE JOINT.
<span>Hinge
joints allow swinging movement of the bones; the joint allows bones to either
move toward one another or to spread apart. Hinge joint is also found in the
ankles, fingers, toes and knees.
73) Knuckle joints: is an example of CONDYLOID JOINT.</span>
A
condyloid joint is a type of joint which allows for movement in two planes,
allowing for flexion, abduction, adduction, extension and circumduction. This
joint usually forms where the head of one bone fits in the elliptical cavity of
another bone. It is similar to ball and socket joint but does not allow a bone
to rotate inside the joint.
74)
Joint between atlas and axis: is an example of PIVOT JOINT.
<span>Pivot joint is a type of joint which allows
rotational movement of bones. This type of joint is found in the neck
vertebrae. The joint is also called rotatory joint.
</span><span><span>
A) </span>Short bone: refers to those bones which are
as wide as they are long. The principal function of short bone is to provide
support and stability with little or no movement.</span>
In the question given, the bone in number 75
[tarsals] is a short bone.
<span>
B) Irregular bone: irregular bones are multipurpose in function; their
functions include protection, provision of multiple anchor points for skeletal
muscle attachments and maintenance of attachments. The bone given in number 79
is an irregular bone. The atlas is a vertebra which protects the spinal cord.
</span>
C) Flat bone: The major role of flat bones is
to provide extensive protection or to provide a broad surface which can be used
for muscular attachments. They are usually flat and broad in form. Examples of
this type of bone are cranium, ilium, sternum and the rib cage. The bone given
in number 80 and 82 are flat bones.
D) Long bone: long bones are usually hard and
dense, with a shaft and two heads. Their major role is provision of strength,
structure and mobility.
<span>The bones in number 76, 77, 78 and 81 are all
examples of long bones.</span><span>
</span>
