Flashcards in Skeletal System Deck (121)
How are lamellae of bone arranged
concentric circles around Haversian canals
Within the lamellae of concentric rings lie the.....
lacuna with osteocytes
Extend between adjacent lamellae
Do red blood cells have nuclei
Do RBC divide when out of marrow?
What is RBC main function
to transport oxygen
In children, red marrow also called ___? is _____ and resides where?
also called myeloid tissue is hemopoietic (blood maker) and fills the medullary cavity
pertaining to the marrow
formation of blood/blood cells
Where is most of the marrow in adults? (age 30)
in the medullary cavity; its YELLOW marrow that stores fat (long bones)
In older adults (age 70), what is yellow marrow mostly replaced with?
Gelatinous marrow- no tremendous function; bones become more fragile
making of bone
Occurs within a membrane of soft tissue that represents the location of a future flat bone (ref. to skull). Its cells differentiate into osteogenic cells and osteoblasts, (in skull of fetus) and trabecular are formed
What did the bones of the skull used to be?
membrane of soft tissue
How do osteoblasts form bone?
they form on the trabecular and lay down an organic matrix and deposit calcium phosphate within it; when trapped, they become osteocytes.
cartilage stops diving so bones won't grow anymore
bone formation using a cartilage model. in the center of the model is the primary ossification center where lacunae enlarge and minerals are deposited around them. (cartilage becomes bone)
Whats the primary ossification center for endochondral ossification?
cells of the PERICHONDRIUM develop into a periosteum (bone lining) where osteogenic cells and osteoblasts produce bone on the OUTSIDE of the model
Where on the cartilage model is bone produced
Outside of it
What is formed on the inside in the center of the cartilage model in endochondral ossification
A primary marrow space is formed
What is the metaphysis?
The transition between the head of hyaline cartilage and the primary marrow space; "meta-" = middle and "-physis" = to grow
How many zones does the metaphysis exhibit that represent the stages of ossification
Where do secondary ossification centers form at birth?
In the epiphyses of long bones
What happens to the epiphysis at the secondary ossification center
It's hollowed out from the center outward and is replaced by bone
Where does cartilage remain until adulthood?
at the epiphyseal plate
Deficiency of vitamin A
retards bone development
deficiency of vitamin C
results in fragile bones
deficiency of vitamin D
rickets: metabolic disorder: phosphorous/calcium
osteomalacia= bone softening