Bone cells + Bone structure

Bone cells

Osteoblasts, osteocytes, osteoclasts

What do osteoblasts do

Synthesize and secrete collagen fibers and other organic compounds of bone matrix, initiate the process of calcification

Where are osteoblasts found

Periosteum and endosteum

What are osteocytes

Osteoblasts that have become trapped by the secretion of matrix

What do osteocytes do

Responsible for maintaining the bone tissue

What are osteoclasts

Huge cells derived from the fusion of as many as 50 monocytes

What do osteoclasts do

Digest bone matrix for bone growth, development, maintenance and repair

Bone resorption

When osteoclasts digest bone matrix

Where are osteoclasts

In the endosteum

How do osteoclasts digest bone matrix

They secrete digestive enzymes into the PM on the side that faces the bone surface and pump out hydrogen ions to eat away at the matrix

Why do we want a cell that eats away at bone?

Bone is a very dynamic tissue

Osteoblasts and minerals

Work together as a negative feedback loop to make sure the amount of —- is good

Ruffled border of plasma membrane

Increases surface area, releases enzymes that break down fibers and bone

What does bone matrix consist of?

1/3 organic and 2/3 inorganic components

Organic component of bone matrix

Protein/collagen fibers

What does collagen do to the bone

Provides it with resilience and the ability to resist stretching and twisting

Inorganic component of bone matrix

Minerals - calcium and phosphorous

Order of bone cells

Osteoprogenitor→osteoblasts→osteocytes

Osteoprogenitor cells function simple

Stem cells- turn into other cells

Osteoblasts function simple

Build bone- trapped in bone

Osteocytes function simple

For repair

Monocytes function

Attack bad cells to help immune system

Salts of the bone matrix

Calcium phosphate and calcium hydroxide

What do the salts of the bone matrix do?

Interact to form a compound called hydroxyapatite