Lab #3 (exercise 7-1)

What are the two general forms of osseous tissue?

Compact bone and spongy bone.

What is the periosteum?

The outer covering of a bone.

What type of connective tissue makes up the fibrous layer of the periosteum?

Dense irregular connective tissue.

What do perforating fibers do?

Anchor the periosteum to the underlying bone.

What are osteogenic cells?

Cells that can develop into osteoblasts.

What are osteoblasts?

Bone-building cells that secrete the organic components of bone ECM.

What are osteoclasts?

Bone-destroying cells that break down bone ECM.

What are osteocytes?

Mature bone cells that monitor and maintain bone ECM.

What is bone remodeling?

The continual process of breaking down old bone and building new bone.

What cells break down bone during remodeling?

Osteoclasts.

What cells build new bone during remodeling?

Osteoblasts.

What is osseous tissue?

Specialized connective tissue that makes up bone.

Where is compact bone located?

On the external surface of bone, deep to the periosteum.

What is the basic structural unit of compact bone?

Osteon.

What is another name for an osteon?

The basic structural unit of compact bone.

What is the central canal?

The longitudinal passageway in the middle of an osteon containing blood vessels and nerves.

What surrounds the central canal?

Concentric lamellae.

What are lamellae?

Rings or layers of bone ECM.

What are concentric lamellae?

Rings of bone ECM surrounding the central canal.

What are interstitial lamellae?

Old lamellae located between osteons.

What are circumferential lamellae?

Lamellae lining the outer and inner surfaces of compact bone.

What are lacunae?

Small cavities between lamellae that contain osteocytes.

What are canaliculi?

Tiny canals connecting neighboring lacunae and osteocytes.

What are perforating canals?

Canals that run perpendicular to osteons and connect blood vessels and nerves between adjacent osteons.

What is the endosteum?

A thin membrane lining internal bone surfaces.

What does the endosteum contain?

A small amount of fibrous connective tissue and a cellular layer containing osteoblasts, osteoclasts, and osteogenic cells.

Where are blood vessels and nerves found in an osteon?

In the central canal.

How do central canals and perforating canals differ?

Central canals run through the middle of osteons; perforating canals run perpendicular to osteons and connect them.

What is spongy bone?

Bone located internally that consists of a latticework of trabeculae.

What are trabeculae?

Tiny bone spicules that make up spongy bone.

What is found between the trabeculae of spongy bone?

Bone marrow.

What are the two types of bone marrow?

Red bone marrow and yellow bone marrow.

What does red bone marrow do?

Produces blood cells.

What is yellow bone marrow primarily composed of?

Adipose tissue.

Does spongy bone contain osteons?

No, its trabeculae are not organized into osteons.

What structures are found in both compact and spongy bone?

Lamellae, osteocytes in lacunae, and canaliculi.

What is the main difference between compact and spongy bone organization?

Compact bone is organized into osteons; spongy bone is organized into trabeculae.

How do you identify compact bone on a model/slide?

Look for circular osteons with central canals and concentric lamellae.

How do you identify spongy bone?

Look for a latticework of trabeculae with spaces containing bone marrow.

What structure looks like rings around a central canal?

Concentric lamellae.

What structure looks like small spaces between lamellae?

Lacunae.

What tiny lines connect the lacunae?

Canaliculi.

What is the central circular opening in an osteon?

Central canal.