Chapter 6: In this chapter, we learned about the physiology of bones. By first exploring skeletal cartilages, and then understanding the functions of bones, developmental aspects of bones, bone classification, and repairing bones.
Background Info
Upstream Causes
Downstream Causes
Direct Cause
Indirect Cause
He was running and fell forward on his right arm
Trauma caused brake
Diet
Mostly eats junk food
Child does not consume enough calcium
Overall: Trauma caused the brake, bones were not as strong as they should be due to lack of calcium
Fracture Classification
Position of Bone
Completeness of Break
Whether skin is Penetrated
Open: skin penetrated
Closed: skin not penetrated
nondisplaced: ends retain normal position
displaced: ends are out of normal alignment
complete:broken all they way through bone
incomplete: not broken all the way through bone
Epiphyseal plate
Location: part of bone between diaphysis and epiphysis
Role: where new bone growth and remodeling takes place
Bone Growth
Ossification: process of bone tissue reformation
endochondral ossification: bone forms by replacing hyaline cartilage, form most of the skeleton
intramembranous ossification: bone develops fibrous membrane
Postnatal
- ossification centers are formed when mesenchymal cells cluster and become osteoblasts
- osteoid is secreted the calcified
- woven bone is formed when osteoid is laid down around blood vessels, resulting in trabeculae
- compact and spongy bone form, and red marrow appears
1.bone collar forms around diaphysis of cartilage model
- central cartilage in diaphysis calcifies and dies, then develops cavities
- periosteal bud invades cavitie, forming spongy bone
- diaphysis elongates, and medullary cavity froms
- epipyses ossify, hyaline cartilage remains in epipyses plates and articular cartialges
long bones grow length wise by interstitial growth
bones increase thickness through appositional growth
bones stop growing during adolescence
Bone remodeling
bone remodeling
bone resorption
bone deposit
function of osteoblasts
requires: vitamin D, vitamin C, calcium and phosphate
consists of both bone deposit and bone resorption
occurs at surfaces of periosteum and endosteum
packets of adjacent osteoblasts and osteoclasts coordinate remodeling process
occurs at different rates in different bones and even different parts of the same bones
function of osteoclasts
secrete lysosomal enzymes and protons that digest matrix
digested products are released into interstitial fluid and then into blood
once resorption is complete osteoclasts undergo apoptosis
Stages of bone healing
hematoma formation
torn blood vessels hemorrhage, forming mass of clotted blood called hematoma
fibocartilaginous callus formation
capillaries grow into hematoma
fibroblasts, cartilage, and osteogenic cells begin reconstruction of bone
this mass of repair tissue is called fibrocartilaginous callus
bony callus formation
within one week, new trabeculae appear in fibrocartilaginous callus
callus is converted to bony calls of spongy bone
bone remodeling
osteoclasts remove excess bony material
compact bone is laid down to reconstruct shaft walls
final structure resembles original structure because responds to same mechanical stressors
anatomy of long bone
diaphysis: shaft that forms long axis of bone
epipyses: ends of long bones that consist of compact bone externally and spongy bone internally
may be distal and proximal
epiphyseal line: between the diaphysis and epiphyses
compact bone: dense outer layer on every bone that appears smooth and solid
spongy bone: made up of honeycomb of small flat pieces called trabeculae
yellow and red bone marrow are in the open spaces of trabeculae
Fracture
upper arm: open due to skin penetration, compete, since it is through the skin, and is displaced since it is out of alignment
fragments of bone on the wound would be a comminuted break, since it was broken into peices
Overall
the boys diet had something to do with the fracture, bones are not mineralized and strong
elbow/upper arm is going to result in a cast and sling, stabilization is key to healing
He is young, he should heal just fine and have a faster recovery due to the fact that his bones are still growing