The Skeletal System Flashcards
What are the 5 functions of the skeletal system?
1) Support the body’s structure
2) Protects internal organs
3) Leverage for movement
4) Stores Calcium
5) Produces blood cells
What are the 2 bone functions?
1) Hard, yet brittle
2) Strong, yet flexible
What compound is responsible for the bone’s function of hard, yet brittle?
HYDROXYAPATITE (inorganic) - this compound contains mineral salt deposits (calcium carbonate and calcium phosphate)
What compound is responsible for the bone’s function of strong, yet flexible?
OSTEOID (Organic) - this compound contains collagen and protein complexes
What are the 4 types of cells contained in bones?
1) Osteogenic stem cells
2) Osteoblasts
3) Osteoclasts
4) Osteocytes (mature bone cells)
What are osteogenic stem cells?
Contained in the epistem and peristem. Responsible for new bone growth.
What are osteoblasts?
They secrete osteoids to become osteocytes. They deposit minerals.
What are osteoclasts?
They remove minerals from bones and release into the circulation. Important for bone remodelling.
What are the osteocytes?
Mature bone cells that are found in the lacunae (nests) of bones and they maintain the matrix
What percentage do cells make up out of the whole bone mass?
2%
What are the 2 difference types of tissue which make up bones and what is their role?
1) Compact Bone (around the outside) - needs to be able to resist stresses
2) Cancellous Bone (inside) - needs to be able to be light so you can move around
What are the 2 components of compact bone?
1) Osteons (functional unit)
2) Lamellae (rings of flat sheets around the osteons)
What are the 3 types of lamellae?
Concentric - around osteons
Interstitial - between the osteons
Circumferential - around all the osteons
What is the importance for the osteons to be positioned in the same direction?
It will increase unidirectional strength
What are the 2 components of cancelleous bone?
1) Trabeculae (tissue elements)
2) Bone marrow (contained within the spaces between the trabeculae)
What are the 2 types of bone marrow?
1) Red bone marrow (aka myeloid tissue) = (located in the spaces at the heads of long bones) produces red blood cells
2) Yellow bone marrow (aka fatty tissue) = can no longer produce red blood cells
Who has more red bone marrow in the heads of their long bones?
Children as they require more RBC’s to grow.