describe the functions of the skeletal system
For support, protection, produces red blood cells, and is a reservoir for minerals and fat
how are bones classified
-long bones
-short bones
-flat bones
-irregular bones
-sesamoid bones
what is the difference between red and yellow bone marrow
- the amount of red marrow you have decreases with age
- red marrow is needed for children to grow
what is the function of osteoblasts
- bone building cells
- perform bone deposition
what is the function of osteocytes
no longer metabolically active
what is the function of osteoclasts
bone resorption
bone formed by intramembranous ossification are built on ___
model (starting material) membrane of embryonic connective tissue
bone formed by endochondral ossification are built on ___
model of hyaline cartilage
what bones are intramembranous ossification responsible for?
- flat bones
- the skull and clavicles
what bones are endochondral ossification responsible for?
all bones below the head except for the clavicles
how do long bones grow in length?
longitudinal growth (division of chondrocytes in epiphyseal plate)
what is the longitudinal and appositional growth
longitudinal is growth in length while appositional is growth in width
describe bone deposition
osteoblasts deposit bone
describe bone resorption
osteoclasts secrete hydrogen ions onto the bone to break it down
what are some factors that effect bone deposition
- compressional load, exercise and testosterone (increases osteoBLASTS)
- inadequate exercise, dietary lack in calcium + vitamins C, D, or K (decrease
osteoBLASTS)
what are some factors that effect bone resorption
- continuous pressure on bone + parathyroid hormone (increase osteoCLASTS)
- estrogen + calcitonin (decrease osteoCLASTS)
what does calcitonin, parathyroid hormone, and vitamin D partake in?
bone remodelling
what does calcium ion partake in?
when they is more calcium ion, it slows bone resorption
when there is less calcium ion, it speeds up bone resorption
