Chapter 6 Flashcards
Bone
an organ made up of several different tissues working together: bone (osseous) tissue, cartilage, dense connective tissue,
epithelium, adipose tissue, and nervous tissue.
The entire framework
of bones and their cartilages constitute the
Skeletal System
The study
of bone structure and the treatment of bone disorders is referred to as:
Osteology
Skeletal System Basic Functions:
Support, Protection, Assistance in Movement, Mineral Homeostasis, Blood Cell Production, Triglyceride Storage
Parts of a Long Bone
Diaphysis, Epiphysis, Metaphyses, Articular Cartilage, Periosteum, Medullary Cavity, Endosteum
The bone’s shaft
or body—the long, cylindrical, main portion of the bone:
Diaphysis
The Epiphyses
are the proximal and distal ends of the bone
Metaphyses
the regions between the diaphysis and the epiphyses. In a growing bone, each metaphysis contains an epiphyseal (growth) plate.
The articular cartilage
is a thin layer of hyaline cartilage covering
the part of the epiphysis where the bone forms an articulation (joint)
with another.
Periosteum
a tough connective tissue sheath and its associated blood supply that surrounds
the bone surface wherever it is not covered by articular cartilage.
Medullary Cavity
a hollow, cylindrical space within the diaphysis that
contains fatty yellow bone marrow and numerous blood vessels in adults.
Functions of Bone tissue
Supports soft tissue and provides attachment for skeletal muscles.
2. Protects internal organs.
3. Assists in movement, along with skeletal muscles.
4. Stores and releases minerals.
5. Contains red bone marrow, which
produces blood cells.
6. Contains yellow bone marrow, which stores triglycerides (fats).
Endosteum
a thin membrane that lines the medullary cavity. It contains a single layer of
bone-forming cells and a small amount of connective tissue.
Bone/Osseous Tissue
Contains an abundant extracellular matrix that surrounds widely separated cells. The extracellular matrix is about 15% water, 30% collagen fibers, and 55% crystallized mineral salts.
Four types of cells present in bone tissue:
osteoprogenitor
cells, osteoblasts, osteocytes, and osteoclasts
Osteoprogenitor cells
are unspecialized bone stem cells derived from mesenchyme, the
tissue from which almost all connective tissues are formed. They are the only bone cells to undergo cell division; the resulting cells
develop into osteoblasts. Osteoprogenitor cells are found along the inner portion of the periosteum, in the endosteum, and in the canals within bone that contain blood vessels.
Osteoblasts
Bone-building cells. Synthesize and secrete collagen fibers and
other organic components needed to build the extracellular matrix
of bone tissue, and they initiate calcification
Osteocytes
mature bone cells, are the
main cells in bone tissue and maintain its daily metabolism, such
as the exchange of nutrients and wastes with the blood.
Osteoclasts
are huge cells derived
from the fusion of as many as 50 monocytes (a type of white blood cell) and are concentrated in the endosteum.
bone resorption
breakdown of bone extracellular matrix. part of the normal development, maintenance, and repair of
bone.
Compact Bone Tissue
Contains few spaces and is the strongest form of bone tissue. Found beneath the periosteum
Compact bone tissue is composed of repeating structural units
called
Osteons
Each osteon consists of:
concentric lamellae arranged around an osteonic (haversian
or central) canal.