Bone Structure and Function Flashcards
Difference between bones and cartilage in respect to nerves.
Bones are rich in nerves whereas cartilage has no nerves
What is the area between the diaphysis and epiphysis called?
Metaphysis
What feeds osteons with nutrients?
Haversion canals
What are two types of bone?
Spongy and compact
What are three types of cartilage?
Hyaline
Fibro
Elastic
What type of growth pattern do bone and cartilage have respectively?
Bidirectional
Unidirectional
What is bone matrix made up of?
Calcium and potassium-based hydroxyapatite
What is the organic proteins found in bone and cartilage respectively?
Ossein
Chondrin
What is the difference between bone and cartilage matrix?
Bone is inorganic and organic
Cartilage is only organic
All cells in bone originate from mesenchymal stem cells except for?
Osteoclasts
Where do osteoclasts arise from?
Granulocyte/monocyte progenitor cell
How are osteoclasts formed?
Granulocyte/monocyte progenitor cell -> inactive osteoclast -> active osteoclasts (multiple come together multi-nucleated)
Where do osteocytes come from?
Osteoblasts that have become trapped in the matrix they formed
What role do osteocytes play in bone maintenance?
Absorb and place bone matrix
Sense density of bone
Stress sensors
Maintain calcium ion level in blood
Describe the outer layer of periosteum
Thick, tough, highly vascular irregular dense CT
Describe inner layer of periosteum
Thin osteogenic layer with osteoprogenitor cells
What is the endosteum?
Single layer of flat osteoprogenitor cells that lines all internal bone surfaces (marrow cavities)
What bones are formed by intramembranous ossification?
Skull, mandible, and clavicle
What are the steps in intramembranous ossification?
Primary ossification centers for when osteoblasts surround growing vessels to form spicule islands and fuse into spongy bone trabeculae
What is unique about intramembranous ossification?
Bone is formed by replacing primitive mesenchymal CT
What does intramembranous ossification look like?
Spongy bone between two compact bone plates
What are steps in primary endochondral ossification?
- Periosteal Collar laid down by osteoblasts in perichondrium
- Chondrocytes destroyed and cartilage matrix calcified to form spicules in diaphysis
- Osteogenic bud (capillaries & osteoprogenitor cells) invades spaces left by chondrocytes
- Osteoprogenitor cells osteoblasts begin to lay down bone matrix
Red marrow function
Hematopoiesis
At birth all is red
Yellow marrow function
Adipocytes in medullary cavities
Yellow-> red marrow in blood loss
What is aggrecan made of?
Proteoglycans linked to hyaluronic acid
Characteristics of territorial matrix
Rich in GAG and poor in collagen, surrounds each chondrocyte and stains blue
Characteristics of interterritorial matrix
Rich in collagen fibers
What type of collagen is found in all three cartilage?
Type II collagen
What collagen is found in fibrocartilage?
Type I collagen
What happens early in osteoarthritis?
Disruption of matrix-molecular framework increasing water content and decreasing PGs
Thickening of subchondral bone
What would happen to bone without mineral?
It would be flexible
What would happen to bone without collagen?
It would shatter
