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Chapter 7 – Bone Tissue
I. Tissues and Organs of the Skeletal System: The skeletal system is composed
of bones, cartilages, and ligaments joined tightly to form a strong, flexible
framework for the body.
A. Functions of the Skeleton – the skeleton plays at least six roles:
1. Support for the muscles
2. Protection for vital organs
3. Movement from the actions of muscles on bones
4. Electrolyte balance – the skeleton stores calcium & phosphate
ions and releases them into the tissue and blood.
5. Acid-Base balance – bone buffers the blood’s pH by
absorbing/releasing alkaline salts.
6. Blood formation – red bone marrow is the major producer of
blood cells.
B. Bones and Osseous Tissue
1. Osseous tissue – connective tissue in which the matrix is
hardened by the deposition of calcium phosphate and other
minerals.
a. The hardening process is called mineralization or
calcification.
C. The Shapes of Bones – classified into four groups:
1. Long bones – longer than they are wide. Examples include the
humerus, radius, ulna, femur, tibia, fibula, etc.
2. Short bones – nearly equal in length and width. Examples are
the carpal and tarsal bones.
3. Flat bones – enclose & protect soft organs; provide broad
surfaces for muscle attachment. Examples include most
cranial bones & the ribs; sternum, scapula, and os coxae.
4. Irregular bones – have elaborate shapes that do not fit into any
of the preceding categories. Examples include the vertebrae
and some skull bones.
D. General Features of Bones
1. Compact (dense) bone – long cylinder of bone that encases a
space called the medullary or marrow cavity.
a. medullary cavity – contains bone marrow
