bone cells and histology

Stem cells: called ____ CELLS

OSTEOPROGENITOR

stem cell mitosis makes

creates one stem cell and one osteoblast

what does progenitor mean

precursors

• Attach to outermost layer of bone when they become osteoblasts

• Are in the periosteum and endosteum

bone stem cells

• Secrete collagen, glycoproteins, induce formation of inorganic matrix, form new bone, remodel existing bone

• Synthesize new bone matrix on top of the already existing ones (called appositional growth)

osteoblasts

what type of cell is located in the periosteum and endosteum

osteoblasts

what type of bone matrix is made up of: calcium salt that makes bone hard

inorganic matrix

what type of bone matrix is made up of: collagen (ground substance), glycoproteins

organic matrix

• A previous osteoblast surrounded by the bone that it made

• Long life

• stabilize and maintain the bone matrix

osteocytes

which type of cell lives in the lacuna within the bone

osteocytes

which type of cell is Connected to one another via canal so they can share ions, signaling, nutrients, etc

• can also share interstitial fluid

osteocytes

which type of cell

• Reabsorbs calcified bone matrix

• Does not come from the same stages of the other ones 

• Absorb the matrix that the osteoblasts just made

osteoclasts

• made from red bone marrow, is a type of WBC that can turn into macrophages who swallow and destroy bacteria 

monocytes

Some fuse together to make a large cell, each of them donate a nucleus and their cytoplasm, these ____ form an OSTEOCLAST

monocytes

•  feet like features surrounding the bottom of the cell that allow the osteoclast to attach to the bone surface

  • Makes a water tight seal to prevent ECF from leaking in

podosomes/podocytes

• in osteocytes, Proton pumps start to pump hydronium ions, but they have nowhere to go because the podosomes sealed everything in

  • This allows for the solution to get more ____, which breaks down the inorganic matrix

acidic

breaking down bonds via water

hydrolysis

Hydrolytic enzymes break down

organic matrix

cell swallows ECF to bring into cell

Endocytosis

material is released from cell surface

Exocytosis

• bring in material, then transport across the cell then the vesicles fuse with the cell membrane from the opposite side, then exocytose the contents of the vesicles on the other side of the cell

Transcytosis

• increase surface area of the bottom of the cell.

  • Increases proton pumps

  • More area for vesicles to land and dump the hydrolytic enzymes

ruffled borders

• Ground substance (proteoglycan aggregates (like a glycoprotein), hyaluronic acid, etc.) NONFRIBROUS

  • Glycoproteins increase the viscosity/slipperyness

  • Hyaluronic acid also makes things slippery

• Extracellular fibers are laid down after the ground substance 

  • Most extracellular fibers are type 1 collagen

  • Very strong

organic matrix in bone matrix

• Hydroxyapetite: salt crystals

  • Has calcium ions and phosphate ions that come together to neutralize each other 

  • They are hard

  • Not degradable by microorganisms

• Gives the bone compressive strength but has its limit

inorganic matrix in bone matrix