Osteo 100 Flashcards
What is Bone?
Bone is an organic (living) tissue with a complex internal and external structure
made up of two components
component 1
ORGANIC MATERIAL: Cells (osetoprogenitor, osteoblasts, osteoclasts, and
osteocytes) and Collagen Fibres.
component 2
MINERALS: Hydroxyapatite (bone mineral: Ca3 (PO4) 2 (OH) 2) and Calcium
Carbonate.
bone has 6 main functions
1 -Support 2- Protection 3- Assistance in movement 4- Mineral (phosphorus, calcium, etc.) homeostasis 5- Hemopoeisis: blood cell production 6- Triglyceride storage (fat storage)
bone remodeling
Is an ongoing process, where new bone replaces old or injured bone tissue This
involve
bone re-absorption
- the removal or ingestion of minerals and collagen
fibres from the bone by osteoClasts. Consume
bone deposition
the addition or deposition of minerals and collagen
fibres to the bone by osteoBlasts. Build
COMPACT / DENSE BONE
Found in the external layers of all bones. Compact bone
has a concentric ring structure.
SPONGY / CANCELLOUS BONE
Found in the interior of most bones; it appears as an
irregular latticework
bone reabsorption and deposition
This occurs at different rates for different regions of the body. Areas of bone that
have greater stress will require more frequent remodeling.
o Bones remodel along lines of mechanical stress. An example: the mechanical stress
on the proximal end of the humerus as opposed to its shaft.
o There needs to be a balance between the amount of injured or damaged bone
reabsorption compared to the amount of new bone created and deposited.
o This process of remodeling allows calcium reserves within the mineral portion
bone to become available for use by other tissues in the body such as nerve and
muscle cells.
o Bone tissue maintains the correct level of calcium within the blood by releasing
or reabsorbing calcium into or from the bloodstream.
o The exchange of calcium and phosphate ions between blood and bone is
regulated by hormonesparathyroid and calcitonin.
types of bone
LONG BONES:
The length is greater than the width. Made up of compact bone with spongy
bone tissue in the ends.
SHORT BONES:
The length and width are close to equal in size. Cubic shaped. Made up mostly
of spongy bone with a thin layer of compact bone.
IRREGULAR BONES:
Complex and varied shapes.
Amounts of spongy and compact bone vary.
FLAT BONES:
Thin bones composed of two nearly parallel plates of compact bone
surrounding a layer of spongy bone.
SESAMOID BONES:
Small bones found within a tendon where a large amount of friction tension
is present. The function is to protect the tendon and underlying joint from
excessive wear and tear as well as provide a mechanical advantage at a joint.
SUTURAL (Wormian) BONES:
Very small bones located in the sutures between cranial bones.
DIAPHYSIS
shaft of bone
EPIPHYSIS
The distal and proximal ends of the bone
METAPHYSIS
The area between the diaphysis and epiphysis. Growing bones have
epiphyseal growth plates at the metaphysis, while mature bones have an
epiphyseal line.
MEDULLARY CAVITY
The space within the diaphysis. In children this contains red bone marrow, and
as the bone matures it becomes occupied with yellow bone marrow.
