Bone Physiology Flashcards
yellow bone marrow
fat storage tissue, mainly found in long bones
newborns don’t have any yellow bone marrow - overtime, convert some red bone marrow to yellow bone marrow
red bone marrow
primarily produces red blood cells
mainly found in short & flat bones
newborns only have red bone marrow
medullary
bone marrow cavity that extends throughout diaphysis
diaphysis
center length of bone
spongy bone
layer surrounding medullary, thickest at ends of bone
contains many bony bar and plates (which follow stress lines) separated by irregular spaces
lighter than compact bone but still strong
proximal epiphysis & distal epiphysis
thick layers of spongy bone at each end of the bone
compact bone
solid outer layer of bone
contains many osteons
osteons
contain osteocytes within tiny lacunae
lacunae arranged in concentric circles around center canals, separated by matrix
osteocytes
bone cells, found w/in osteons
lacunae
tiny chambers within osteons that hold osteocytes
center canals
canals within osteons that contain blood vessels & nerves
bring nutrients for the bone to renew itself
matrix
network of collagen protein fibers & mineral deposits (mainly Calcium + Phosphorus salts) that separates lacunae
osteoclasts
bone absorbing cells
break down bone, remove worn cells, and deposit Calcium into blood
osteoblasts
repair osteoclasts’ damage
form new bone by taking Ca from blood
osteocyte formation
when osteoclasts or osteoblasts get stuck in the matrix, they are converted into osteocytes and become new bone tissue)
prenatal bone development
in fetus, most bones are cartilaginous structures in the shape of future bones
ossification
process of converting cartilaginous models of bones into bone - Ca salts are deposited into the matrix by precursor cartilaginous cells and then by osteoblasts
endochondrial ossification
ossification of long bones from hyaline cartilage
- starts within primary ossification structure in middle of bone
- cartilage cells begin dying, so blood vessels penetrate the bone to deliver osteoblasts
- this forms that medullary cavity + secondary centers form at ends of bone
- cartilaginous disk (growth plate) remains between primary + each secondary center until completely ossified during puberty –> bone stops growing, reaches full adult height
intramembranous ossification
formation of fetal bones from connective tissue (occurs during different parts of embryonic dev)
- starts with mesenchymal cells differentiating into osteoblasts
- osteoblasts secrete bone tissue
- once secrete enough bone tissue, osteoblasts become osteocytes
