2.1 Bone Structure, Bone Cells, & Bone Formation

What are two ways to describe compact (cortical) bone tissue?

Dense & Smooth

What is compact tissue also called?

Cortical Tissue

Where is compact (cortical) tissue found?

On the outside of the bone

Where is spongy bone tissue found?

On the inside of the bone

What is one word to describe spongy bone tissue?

porous

What is compact bone made of?

Osteons

What are osteons?

Long cylinders that act as tiny weight-bearing pillars in the bone

What are osteons made of?

a group of hollow tubes called lamella

What is the thing that runs through the middle of each osteon and contains small blood vessels and nerve fibers?

Harversian canal (central canal)

Which is more organized, spongy bone or compact bone?

Compact bone

Does spongy bone have osteons?

No

What are trabeculae?

tiny bone struts that are key for helping the bone to resist stress

Where is bone marrow found?

trabeculae

What do bone markings correspond to?

how the bone and its attached muscles and ligaments work together

What are the three types of bone markings?

Projections, surfaces, depressions and openings

What type of bone marking is where muscle and ligament attach?

projections

What type of bone marking form joints?

surfaces

In what type of bone marking will you find blood vessels and nerves running through?

depressions and openings

What do osteocytes do?

maintain healthy bone structure

Where are osteocytes housed?

lacunae

What are lacunae?

the gaps between the lamellae

What do osteoblasts do?

Build and construct bones by calcifying bone as it forms

What do osteoclasts do?

regenerate bone through bone remodeling by absorbing bone tissue wherever it is not needed or is degenerating

What is another word for ossification?

osteogenesis

What is the process of bone tissue formation called?

ossification (osteogenesis)

What three things is ossification (osteogenesis) important for?

1) forming your skeleton as an embryo

2) bone growth (childhood to adulthood)

3) bone remodeling and repair

What are the two types of ossification?

1) intramembranous ossification

2) endochondral ossification

Where can you find intramembranous ossification (2 places)?

clavicle and skull bones

What is intramembranous ossification?

when bone develops from a fibrous membrane

What is endochondral ossification?

when bone develops by replacing caritlage

Why is it important that our bone is being constantly remodeled / what would happen if it wasn't?

if it wasn't, the calcium in our bones would crystalize and make the bones more brittle

Why would you be concerned about your bones being more brittle?

more brittle = more likely to fracture

What are the 4 "players" in bone remodeling?

1) osteocytes

2) osteoclasts

3) macrophages

4) osteoblasts

What do osteocytes do in the bone remodeling process?

release chemical signals to tell osteoclasts to go to the damage

What do osteoclasts do in the bone remodeling process?

release enzymes that allow for digestion of calcium phosphate

What is the process where the calcium and phosphate from broken down calcium phosphate (Ca3(PO4)2) is put back into the blood?

resorption

What do macrophages do in the bone remodeling process?

promote bone tissue remodeling

What do osteoblasts do in the bone remodeling process?

come in and build new bone before undergoing apoptosis