Bones, Cartilage and Joints Flashcards
What is the difference between the axial and appendicular skeleton?
- AXIAL - consists of skull, hyoid bone, sternum, ribs etc.
- APPENDICULAR - bones of the limbs
What is cartilage and what does it do?
- Connective tissue - formed of chondrocytes and extracellular matrix
- Provides protection. Bone precursor
Describe cartilage formation. PART 1
- Matrix laid down by chondroblasts
- Surface surrounded by perichondrum
Describe cartilage formation. PART 2
- Chondroblasts develop from perichondrum
- Once chondroblast surrounded itself in matrix, becomes chondrocyte. Space locate in is lacuna
Does the cartilage have blood supply/nerves?
No
How is cartilage nourished?
- Perichondrum supplies cartilage with nourishment and carries away by-products of metabolism
- Both occur by diffusion
What are the three types of cartilage?
HYALINE
FIBROCARTILAGE
ELASTIC
Describe hyaline cartilage.
- Appears glassy on gross examination
- Found in trachea, bronchi and synovial joints
- Equal amounts of collagen and proteoglycans
Describe fibrocartilage
- More collagen than proteoglycans
- Compressible
- Found in knee joint, pelvis and intervertebral discs
Describe elastic cartilage
- Numerous elastic fibres in addition to collagen and proteoglycans
- Found in external ears and epiglottis
What is bone?
- Living tissue
- Formed of extracellular matrix, hydroxyapatite crystals, water and bone cells
What is the function of bone?
- Site of haematopoiesis
- Attachment site for muscles/ligaments
- Mineral storage
What are the different shapes of bone?
- LONG BONES - tubular
- SHORT BONES - cuboidal
- FLAT BONES - protective
- IRREGULAR - variety of shapes
- SESAMOID - protect tendons from excessive wear e.g patella
Describe bone microstructure.
- Matrix laid down by osteoblasts
- Surface of bone has periosteum where osteoblasts develop from
- Becomes osteocyte when surrounded itself in matrix. Space located in is lacuna
- Bone reabsorbed by osteoclasts
What are the two structural forms of bone?
- SPONGY/TRABECULAR BONE - spaces between plates of bone - resembles sponge
- COMPACT/CORTICAL BONE - solid - almost no spaces
How is blood supplied to bone?
HAVERSIAN CANALS
- Contain blood vessels that supply bone
- Surrounded by concentric lamellae
Describe basic bone development.
- OSSIFICATION - bone formed by osteoblasts
- When already bone, new bone added on surface by osteoblasts - APPOSITIONAL GROWTH
When there is no bone, how is new bone formed?
- ENDOCHONDRAL OSSIFICATION - bone replaces hyaline cartilage
- INTRAMEMBRANOUS OSSIFICATION - bone forms in areas with connective tissue ‘membranes’ e.g skull bones
When might endochondral/intramembranous ossification occur?
- When no bone (e.g in developing fetus, children, at puberty)
What are joints?
Junction between two or more bones or rigid parts of skeleton
What are the three types of joints?
SYNOVIAL
FIBROUS
CARTILAGINOUS
What are the types of synovial joints? PART 1
- PLANE JOINTS - permit sliding movements in plane of articular surfaces e.g acromioclavicular joints
- HINGE JOINTS - permit flexions and extensions ONLY - bones joined by laterally placed ligaments e.g elbow joint
- SADDLE JOINTS - also permit abduction/adduction e.g carpometacarpal joint
What are the types of synovial joints? PART 2
- CONDYLOID JOINTS also permit circumduction e.g knuckle joints
- BALL AND SOCKET JOINTS - also permit medial/lateral rotations e.g hip joints
- PIVOT JOINTS - permit rotation around central axis
What are the two types of cartilaginous joints?
- PRIMARY - bones united by hyaline cartilage permitting slight bending during early life
- SECONDARY - slightly movable united by fibrocartilage e.g IV discs
