Fundamentals of Anatomy and Physiology

102 Chapter 5

Function Characteristics and Location

Morphology

Bone (osseous) tissue

Comprises the skeleton of the

body, which supports and protects

underlying soft tissue parts and

organs, and also serves as

attachments for skeletal muscles.

Connective tissue's

intercellular matrix is calcified by

the deposition of mineral salts

(like calcium carbonate and

calcium phosphate). Calcification

of bone imparts great strength.

The entire skeleton is composed

of bone tissue.

Bone cell

Cytoplasm^ Bone^

Nucleus lacunae^

(A) (^)

(B)

Source

Ross/Science Michael ©

(B) Photo

(^) ,
® Learning
Cengage
© (A)
Figure 5- 11 Views of compact bone.
bone in structure but is harder and denser. The crown of the
tooth is covered with another material, enamel, which is
white in appearance. Dentin is light brown. If you ever
chipped a tooth, the brown material you saw under the
white enamel was the dentin. The enamel is secreted onto
the dentin of a tooth by special epithelial cells that make up
the enamel organ. This secretion occurs just be-fore the
teeth break their way through the gums.
Blood and hematopoietic (hee-MAT-oh-poy-eh-
tik) tissue are other examples of specialized connec-tive
tissue. Blood is unique connective tissue in that it is
composed of a fluid portion (the plasma) and the formed
elements of blood: the erythrocytes (eh-RITH-roh-
sightz) or red blood cells and leukocytes (LOO-koh-
sightz) or white blood cells (Figure 5-12). We will discuss
blood in more detail in Chapter 13. Blood cells are formed
in red bone marrow, and some white blood cells are also
formed in lymphoid organs. Marrow and lymphoid organs
are referred to as hematopoietic tis-sue. Blood is liquid
tissue circulating through the body. It transports oxygen,
nutrients, hormones, enzymes, and waste products such as
carbon dioxide gas and urea. It also protects the body
through its white blood cells and helps to regulate body
temper ature.
Lymphoid tissue is another specialized connective
tissue (Figure 5-13). Lymphoid tissue is found in the
lymph glands or nodes, the thymus gland, the spleen, the
tonsils, and the adenoids. Lymph tissue manufac-tures
plasma cells like the B lymphocytes. This tissue’s main role
is antibody production and protects us from disease and
foreign microorganisms.
The reticuloendothelial (reh-tik-you-loh-in-doh-
THEE-lee-al) or RE system consists of those specialized
connective tissue cells that do phagocytosis. Three types of
cells fit into this category. The first type are the RE cells
that line the liver (they get another special name:
Kupffer’s cells) and those that line the spleen and bone
marrow. The second type are the macrophages. These cells
are also referred to as histiocytes or “resting-­wandering”
cells, because they are fixed in tissue until they must
wander to an invader and devour it. Any phagocytic cell of
the RE system can be called a macrophage. The third type
of cell is a neuroglia (noo-ROH-glee-ah), which does
support and a microglia (my-KROG-lee-ah) cell. This is
a phagocytic cell found in the central nervous system.
Other types of neuroglia cells do support.
Synovial membranes line the cavities of freely
moving- joints and are also classified as specialized
connective tissue. These membranes also line bursae,
which are small sacs containing synovial fluid found
between mus-cles, tendons, bones, and skin and underlying
structures. They prevent friction.