Skeletal System Part 2 Flashcards
In embryo, what is the skeleton primarily made of?
Cartilage
Ossification
Bone formation
Osteoblasts
Bone forming cells.
Covers Hyaline cartilage.
When cartilage is broken down, what does it produce?
Marrow
Bone is a …… and a ……. tissue.
Dynamic & Active
What are the two factors that remodel bones?
Calcium levels in the blood& pull of gravity & muscle on skeleton.
Calcium Levels
When calcium levels drop below homeostatic levels, the parathyroid releases parathyroid hormone (PTH) to activate osteoclasts.
When calcium levels in the blood increase, calcium is deposited in the bone matrix.
Pull of Gravity & Muscle on Skeleton
Stress of muscle pull away & gravity action on the skeleton determine where bone matrix is to be broken down or forms so that the skeleton can remain as strong & vital as possible.
Osteoclasts
Giant bone-destroying cells in bones to release calcium.
What are the two classifications of bones fractures?
Closed & Compound
Closed Fracture
Does not penetrate the skin
Compound Fracture
End of bones penetrate through the skin.
Reductions
A realignment of the broken bone ends.
Open Reductions
Surgery & the bone ends are secured together with pins or wires.
Closed Reduction
Bone ends are coaxed back into position by physicians hands.
Comminuted Fracture
Bone breaks into many fragments.
Most common in older people & brittle bones.
Compression Fracture
Bone is crushed.
Common in porous bones.
Depressed Fracture
Broken bone is pressed inward.
Typical of skull fractures.
Impacted Fracture
Broken bone ends are forced into each other.
Commonly occurs when someone attempts to break a fall with an outstretched arm.
Spiral Fracture
Ragged break occurs when excessive twisting forces are applied to a bone.
Common sports fracture.
What are the stages of healing a bone fracture in order?
- Hematoma
- Fibrocartilage Callus Forms
- Bony Callus Forms
- Bone Remodeling Occurs
Hematoma
Hematoma forms (blood-filled swelling)
Fibrocartilage Callus Forms
Growth of new capillaries in the clotted blood at the site of damage.
Removal of dead tissue by phagocytes.
Contains cartilage, bony matrix, & colagen fibers.
Bony Callus Forms
Osteoblasts & Osteoclasts migrate into the area and multiply.
Fibrocartilage callus is replaced by bony callus made of spongy bone.
Bone Remodeling
Bony callus is remodeled in response to the mechanical stresses placed on it.
Forms a new permanent “patch” at the fracture site.
