The Skeletal System Flashcards
What is an osteocyte?
A mature bone cell.
What is the function of an osteocyte?
Control absorption & release of calcium.
What is an osteoblast?
An immature bone cell.
What is the function of an osteoblast?
Building bone (osteogenesis), secreting osteoid to make up the bone matrix.
What is an osteoid?
Unmineralized substance that makes up the bone matrix.
Osteogenesis (ossification)
Process of bone tissue formation
What is an osteoprogenitor cell and what does it do?
Bone stem cell able to differentiate into new osteoblasts
What is an osteoclast and what does it do?
Giant, multinucleated cells that break down & reabsorb bone matrix
What is osteolysis?
The breaking down of bone
What is bone matrix?
The nonliving, structural part of bone made up primarily of calcium
Compare & contrast compact and spongy bone (4 things).
- Compact bone is dense & solid, spongy bone is lightweight.
- Compact is made of osteons, spongy is made of trabeculae.
- Compact is found in areas where stresses are not multidirectional, spongy is where bone isn’t stressed/stresses are multidirectional.
- Compact has 1 central canal of blood vessels, spongy has extensive network of blood vessels and contains red & yellow bone marrow.
What is an osteon?
Functional unit of compact bone.
What is a trabeculae?
Functional unit of spongy bone.
What is the endosteum?
Incomplete cellular layer lining the medullary cavity of a bone.
What is the medullary cavity?
Cavity within the shaft (diaphysis) of the long bones filled with bone marrow.
What is the periosteum?
A dense layer of vascular connective tissue enveloping the bones (except at the surfaces of the joints), make up of 2 layers, fibrous on the outside and connective tissue on the inside.
What is the epiphysis?
Extended the end part of a long bone, largely spongey bone.
What is the metaphysis?
Connects the diaphysis to both epiphyses.
What is the diaphysis?
The central shaft of a long bone, containing the medullary cavity.
What is the epiphyseal plate?
Cartilaginous area at the ends of long bones where interstitial growth takes place in the immature skeleton (fused @ 21 years old).
Bone formation begins with _________, which becomes ______ bone, when then becomes _______ bone.
cartilage, spongy, compact.
What is interstitial growth?
Growth in length
What is appositional growth?
Growth in width.
What are lamellae?
Concentric rings made up of groups of hollow tubes of bone matrix
What is intramembranous (dermal) ossification?
Bone develops directly from embryonic connective tissue.
What is a secondary ossification centre?
Region of bone development in the epiphyses.
What is bone turnover?
Regular replacement of bone cells through osteoclast breakdown and rebuilding through osteoblasts.
What are the 4 general steps of fracture repair?
- Blood clot forms @ site.
- Internal callus forms out of spongy bone & external callus forms out of cartilage.
- Spongy bone replaces cartilage of external callus & dead bone is resorbed & replaced.
- Compact bone forms & evidence of fracture disappears.
What is apoptosis?
Process of programmed cell death.
What are long bones?
Bones that are long & slender (ex: arms and legs).
What are flat bones?
Bones that are thin, flattened, and usually curved (ex: skull, ribs)
What are pneumatized bones?
Bones that are hallow or contain numerous air pockets (ex: ethmoid).
What are irregular bones?
Bones with complex shapes & flat, notched or ridged surfaces (ex: vertebrae and face).
What are short bones?
Bones that look boxlike (ex: carpals and tarsals).
What are sutural bones?
Tiny bones between cranial bones.
What are sesamoid Bones
Round bones found near joints (ex: the patella).
What is a process?
Prominent projection/bump on a bone
What is a ramus?
An extension of a bone making an angle with the rest of the structure
What is a sinus?
Cavity within a bone, filled with air and lined with mucous membrane
What is a foramen?
Round or oval opening through a bone
What is a fissure?
An opening; a groove; a split
What is a meatus?
Canal-like passageway
What is a sulcus?
A narrow groove
What is a fossa?
A shallow depression
What is a trochanter?
A large, rough projection.
What is a crest?
A prominent ridge on a bone.
What is a spine?
A pointed process.
What is a line?
A narrow ridge of bone; less prominent than a crest
What is a tubercle
A small, rounded projection.
What is a tuberosity?
A large rounded projection; may be roughened
What is a head?
bony expansion carried on a narrow neck
What is a facet?
smooth, nearly flat articular surface
What is a condyle?
rounded articular projection
What is a trochlea?
a smooth, grooved articular process shaped like a pulley
Osteopenia is a __________ calcification of bone due to inadequate _____________.
decreased, ossification
Osteoporosis is a severe ____ of ____ mass, compromising normal function.
loss, bone.
Cancerous tissues release __________-__________ ______, which stimulates osteoclasts.
osteoclast-activating factor
What are the functions of the periosteum (4)?
- Separates & protects bone from surrounding tissues.
- Point of attachment for blood vessels & sensory nerves.
- Participates in bone growth & repair.
- Connects bone to surrounding connective tissue network.
Bones that have parallel surfaces are ____ bones
flat
Bones that are boxy with approximately equal dimensions are:
Short bones
The type of bone marking that indicates muscle, tendon, and ligament attachment is:
Projection
The types of bone marking that indicates blood vessels and nerve attachment are:
Openings and depressions
Where is spongy bone found in long bones?
Epiphyses
Where is spongy bone found in flat bones?
Between the compact bone layers
Canaliculi are:
Narrow passageways in the matrix connecting lacunae to blood supply
What are the products of monocyte stem cells?
Osteoclasts
In bone, the calcium phosphate forms crystals of:
hydroxyapatite
