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.