Lecture 4a Flashcards
7 functions of bone
support protect anchor/movement mineral storage hematopoiesis (blood cell formation) triglyceride storage hormone production
Tissues types in the bone
bone blood cartilage fat ligaments/tendons
Extracellular matrix
rigid and sturdy
-due to mineral deposit (calcium)
Axial Skeleton
protect and support
Appendicular Skeleton
movement
Major types of bone and description
long bone-greater in length than width
short bone-nearly equal in length and width
flat bone-thin surfaces
irregular bone-complex shape
Compact bone
- solid, smooth and relatively dense bone
- external surface of bone
Spongy bone
- open lattice of narrow plates called trabeculae
- internal surface of the bone
- contains bone marrow
Epiphysis
- knobby ends of long bones
- proximal and distal epiphysis
- covered in hyaline cartilage
Diaphysis
-elongated cylindrical shaft with bone marrow cavity
Medullary cavity
houses the yellow bone marrow
long axis of bone
Metaphysis (epiphyseal plate)
- in between the diaphysis and the epiphysis
- contains the epiphyseal (growth) plate
Periosteum
-outer layer of the bone
-covers external surface
-anchors blood vessels, nerves and tendons and ligaments
-dense irregular connective tissue
outer membrane-fibrous layer
inner membrane-osteogenic layer
Osteogenic layers
osteoprogenitors
osteoblasts
osteoclasts
Endosteum
- within the bone
- covers the internal surfaces of bone including the trabeculae
- same cells as inner layer of the periosteum (osteogenic layer)
Osteoprogenitor cells
- stem cells
- found in the periosteum (inner layer) and endosteum
- differentiate in to osteoblasts
Osteoblasts
- secrete bone matrix (osteoid) - collagen, calcium binding proteins
- when surrounded by the matrix it matures and becomes osteocytes
- responsible for bone growth
Osteocytes
- final mature form of bone cells
- mature bone cells monitor and maintain the bone matrix
- resides in the lacunae
- detects mechanical stressors on bone
- communicates with osteoblast and osteoclasts during bone remodelling
Osteoclasts
- bone dissolvers
- releases calcium
- ruffled membrane that increases the surface to volume ratio
Osteon
- compact bone structure
- contains the lamellae and the central canal
- runs parallel to bone
- weight bearing pillars
Lamellae
- matrix tubes, like the rings of a tree
- contains collagen fibres running adjacent to the lamellae to withstand torsional strain
Central canal
contains blood vessels and nerves
Perforating canal
connects the medullary cavity with the central canal
Canaliculi
tiny canals connecting the lacunae with to eachother and the central canal
Organic component of bone
resists stretch
-bone cells
-osteoid (collagen, bind specific proteins and ground substance)
1/3 of the bone
Inorganic component of bone
resists to compression
-mineral salts (calcium phosphate)
2/3 of the bone
Comminuted fracture
- bone breaks into three or more pieces
- seen in old age, the bones are more brittle
Compressed fracture
bone is crushed
-due to porous bone (osteoporotic bone) subjected to extreme trauma; fall
Spiral fracture
- ragged break due to a twisting force applied to the bone
- most common in sports fractures
Epiphyseal fracture
- the epiphyseal detaches from the diaphysis along the epiphyseal plate
- tends to occur when the cells of the cartilage is dying and the calcification of the matrix is occurring
Depressed fracture
the bone breaks inwards
-commonly seen in head injuries
Greenstick fracture
- when the bone breaks incompletely, one side is broken and the other side is bending
- this is seen in kids since they still have a more organic matrix that is more flexible than adults
What are the projections
- trochanter
- line
- crest
- tubercle
- epicondyle
- spine
- process
- tuberosity
Surfaces
head
facet
condyle
Depressions and openings
notch meatus groove fissure foramen sinus fossa
