Objective 4: Types of bone cells
Osteoblast and Osteocytes are both from
bone cell lineage
Osteoid is made up of
collagen and calcium-binding proteins
Osteoclast cells are from
white blood cell lineage
Collagen makes up ___% of protein and Calcium-binding proteins make up ___%
90;10
Osteogenic cells
-also called osteoprogenitor cells -mitotically active stem cells in periosteum and endosteum -When stimulated, they differentiate into osteoblasts or bone-lining cells -some remain as these kind of stem cells
Osteoclasts
-derived from same hematopoietic stem cells that become macrophages -giant, multinucleate cells function in bone resorption (breakdown of bone)
Osteocytes
-mature bone cells in lacunae that no longer divide -maintain bone matrix and act as stress or strain sensors -respond to mechanical stimuli such as increased force on bone or weightlessness -communicate information to osteoblasts and osteoclasts (cells that destroy bone) so bone remodeling can occur
Osteoblasts
-Bone-forming cells that secrete unmineralized bone matrix called osteoid - Osteoblasts are actively mitotic (undergoing mitosis)
Bone-lining cells
-Flat cells on bone surfaces believed to also help maintain matrix (along with osteocytes) -on external bone surface, these cells are called periosteal cells -on internal surfaces, they are called endosteal cells
Osteoclasts pt2
-When active, cells are located in depressions called resorption bays (SORT of like lacunae for osteocytes) -Cells have ruffled borders that serve to increase surface area for enzyme degradation of bone -also helps seal off area from surrounding matrix
What are the five major types of cells of bone tissue?
1. Osteogenic cells 2. Osteoblasts 3. Osteocytes 4. Bone-lining cells 5. Osteoclasts
Osteoblasts mature into
Osteocytes
Some osteoprogenitor cells become
osteoblast