skeletal system Flashcards
what are the functions of the skeletal system?
- support
- protection of vital organs
- attaches muscles + allows movement
- red marrow produces rbc, wbc
- stores Ca++
when does bone formation begin in the fetus?
on the 8th week.
what is the skeleton of the embryo contructed of before week 8?
fibrous membrane + hyline cartilage.
what are the two different types of bone ossification?
Intramembranous ossification and endochondral ossification.
what are the processes involved with intrmembranous ossification?
- osteoblast produce spongy bone along CT fibres and periosteum forms
- then osteoblasts under it lay down compact bone.
how does endochondral ossification work?
Hyaline cartilage is used as a model for forming bone. this cartilage then ossifies to form spongy bone.
the periostum forms and then osteoblast beneath lay down compact bone.
what do we call growth of bone in length ?
we call it endochondral growth which happens at the epipheaseal plates.
what are the processes of endochondral growth? (growth in length)
cartilage grows, then that matrix near diaphysis becomes bone.
how does Endochondral growth stop?
the epiphyseal plate ossifies and becomes bone.
what do we call growth in diameter?
appositional growth.
what are the processes of appositional growth?
osteoBLAST beneath periosteum secrete bone matrix (on the external side of bone. and the inside become more hollow do to osteoCLASTs (reabsorb bone.
How does moderate exercise affect bone?
increased osteoblast activity in areas of stress and makes bones stronger.
how would an injury that restricts movement impact bone?
it would decrease osteoblast activity + no change osteoclast activity so that would decrease bone mass.
how could weights of electrical currents impact bone healing?
may increase osteoblast activity, which could speed up healing.
what is required for the production of bone matrix?
Calcium and phosphate.
what is required for collagen production?
vitamin C
what increases absorbtion of Ca++ from the intestine?
vitamine D
what is rickets ?
a disease in children where bones are soft and do not form properly/
which two hormones play a big role in bone growth?
growth hormone and thyroid hormone, (tyroid hormone needed to enable the growth hormone)
what does estrogen and testosterone do for bone growth?
they both increase osteoblast activity.
what hormone ossifies the epiphyseal plate?
Estrogen (in both sexes)
what does calcitonin do in bone growth?
inhibits osteoclast activity and increases Ca++ movement in the blood which promotes bone growth.
what does parathyroid hormone do in bone growth.
Increases osteoCLAST acctivity, decreases osteoBLAST activity, and increases Blood Ca++
what happens to bones for patients with osteoporosis?
decreases bone mass.
