Intro to Bone and Soft Tissue Flashcards
What is the purpose of cartilage?
- structural support
- protect tissues
- attachment sites
How many bones are there n the adults compared to children?
-206 in adults and 270 in children
What is the appendicular skeleton comprised of?
- pectoral girdle
- upper and lower limbs
- pelvic girdle
What is the axial skeleton comprised of?
- cranium
- vertebral column
- rib cage
What are the 5 main functionsof the skeletal system?
- movement
- support
- protection of vital organs
- calcium storage
- haematopoesis
What are the classifications of bones by shape?
- flat
- short
- sesamoid
- long
- irregular
- sutured
What type of connective tissue connects bone to bone?
-ligament
What type of one is the patella?
-sesamoid
What are osteogenic cells?
-bone stem cells
What are osteocytes?
- mature bone cells
- formed when osteoblasts become embedded in its secretions
- sense mechanical strain to direct osteoclast and osteoblast activity
What are osteoblasts?
- bone forming
- secrete osteoid
- catalyse mineralisation of osteoid
What are osteoclasts?
- bone breaking
- dissolve and resorb bone by phagocytosis
- derived from bone marrow
Where are osteocytes found?
-embedded in matrix
Where are osteoclasts found?
-bone surfaces and at sites of old, injured or unneeded bone
Where are osteogenic cells found?
-deep layers of periosteum
Where are the osteoblasts found?
-growing portions of bones, including periosteum and endosteum
What is the bone matrix made up of?
- Organic component (40%) :
- Type 1 collagen (90%)
- Ground substance (10%) - proteoglycans, glycoproteins, cytokine and growth factors - Inorganic component (60%):
- Calcium hydroxyapatite
- Osteocalcium phosphate
Tell me about immature bone.
- first bone that is produced
- laid down in a ‘woven’ matter - relatively weak
- mineralised and replaced by mature bone
Tell me about mature bone.
- mineralised woven bone
- lamellar (layer) structure - relatively strong
What are the types of mature bone?
- Cortical (stronger):
- compact, dense
- suitable for weight bearing - Cancellous:
- ‘spongy’ - honeycomb structure
- not suitable for weight-bearing
How do the structure of cortical and cancellous bone differ?
- Cancellous have trabeculae (matrix of inorganic tissue)
- Cortical has lacunae, mineralised matrix and
Tell me about the structure and organisation of compact bone.
- few spaces
- provides protection, support and resides stresses produced by weight of movement
- repeated structural units ‘Osteons’ - concentric ‘lamellae’ around a central ‘Haversian canal’
What is the Haversian Canal?
- found in compact bone
- contains blood vessels, nerves and lymphatics
What are lacunae?
- found in compact bone
- small spaces containing osteocytes
- tiny canaliculi radiate from lacunae filled with extracellular fluid
What is the volkmans canal?
- found in compact bone
- transverse perforating canals
What is intramembranous ossification? (flat sheets)
-bone development from fibrous membranes
-forms flat bones of skull, clavicle and mandible
-mesenchymal cell template
-
1.condensation of mesenchymal cells which differentiate into osteoblasts- ossification centre forms
2. secreted osteoid traps osteoblasts which become osteocytes
3. trabecular matrix and periosteum form
4. compact bone develops superficial to cancellous bone. Crowded blood vessels condense into red bone marrow