marture cartilage cells. Reside in lacunae. Alive, but not doing much.
Extracellular MAtrix (ECM)
any substance produced by cells and excreted to the extracellular space within the tissues, serving as a scaffolding to hold tissues together and helping to determine their characteristics.
made of dense CT. Provides mechanical support and protection.
1. Osseous CT 2.Clacified ECM (Calcium phosphate
1. support and prtect 2. Movement -attchment site for muscles 3. hemopoiesis: red bone marrow -especially in long bones such as the femur 4. Storage of mineral and energy reserves -calcium phosphate and yellow bone marrow
Structure of long bones Part 1 (See diagram on pg 150 of TB)
1. Compact bone -superficial bone tissue 2.Spongy Bone -dense bone tissue 3. Epiphysis -ends of long bones 4. Diaphysis -Shaft 5. Metaphysis -contains the epiphyseal plate 6. Aricular Cartialge -hyaline cartialge covering the ends of bones within a joint
Structure of long bones Part 2 (See diagram on pg 150 of TB)
7. Medullary Cavity -contains yellow bone marrow in adults and red in children 8. Endosteum -layer of cells lining the spongy bone and medullary cavity 9. Periosteum -dense CT outer covering of the bone 10. perforating fibers -attach the periosteum to the compact bone 11. nutrient foramen -conatins nutrient artery
Stem cells derived from the mesenchyme that becomes osteoblast
Immature osteocytes that BUILD bone by secreting osteoid (organic part of ECM)
Mature bone cells that maintain bone matrix. Reside in the lacunae
1. cells that CONSUME bone (bone reabsorption) 2. Phagocytic cells using hydrochloric acid and lysosomes 3.Increase blood Calcium levels
Classification of bone by Histoology
Compact VS Spongy bone
1. AKA cortical bone 2. solid, dense 3. lined by periosteum 4. found in the superficial regions of bone 5. contains osteons
1. AKA cacellous or trabecular bone 2. porous 3. lined by endosteum 4. Found in deeper regions of the bone
Structure of compact bone Part 1 (see diagrams on TB Pg. 154/156)
1. Osteon (haversian system) -basic structural and functional unti 2. Central canal (Haversian Canal) 3.Concetric Lamellae -concetric rings of osseous CT that surround the central canal 4. Osteocytes -mature bone cells
Structure of compact bone Part 2 (see diagrams on TB Pg. 154/156)
5. Lucanae -cavities which house osteocytes 6. Canaliculi -connect neighboring lacunae -allows nutrients to travel btw the cental canal and the osteocytes 7. Perforating ccanals (Volkmann's canals) -connect blood and nerve supply to central canal
Structure of spongy Bone (Pic. on TB Pg. 154)
1. Trabeculae -main structural/ functional component -form criss crossing bars and plates for strength 2. Parallel Lamellae 3.Osteocytes within lacunae 4.Canaliculi -provides nutrients to cells through diffusion
bone growth wi membrane (mesenchyme) -forms flat bones of the skull, some facial bones, mandible, and clavical
Enchondral ossification (Diagram on TB Pg. 159)
Bone growth with in cartilage -turns fetal frmawork of hyaline cartilage into bone - formation of most bones -Primary ossification center in diaphysis and secondary in epiphysis
1. Occurs during childhood and adolesence 2. Intersitial gowth (length) VS. Appositonal Growth (thickening)
Occurs at Epiphysil plates: 1.Chonfroblast neart he epiphysil plate multiply, pushing the epiphysis away from the diaphysis 2. Chondrocytes enlarge; matrix calcifies 3. Chondrocytes die and disentigrate 4. Remodeling by osteoclast
1.simple 2.open/compund 3.stress 4.pathologic
Bone doesn't perice skin
bone pierces the skin
thin break from repetitive loads
Disease weakens the bones
Fracture Repair (Pic TB Pg. 166)
1. Fracture hematoma forms 2. Fibrocartilage (soft) callus forms 3.Hard (bony) callus forms 4. Bone remodeled
Called rickets in small children -Soft bones -leads to bowed legs
excessive bone reabsorptipon. Aged and post menopause.
Other Bone disorders
-Vitamin D deficency -Calcium Deficency
*AKA Paget's disease *Excessive osteoclast and osteoblast function *Bone is unstable and Immature *most common in os coxa, skull, vertebrae, femure, and tibia
What is the function of red bone marrow? Yellow?
Red blood cells, platelets and most white blood cells arise in red marrow; some white blood cells develop in yellow marrow. The color of yellow marrow is due to the much higher number of fat cells. Both types of bone marrow contain numerous blood vessels and capillaries.
In what region of the long bone is the epiphysis plate found?