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Question 1

How are osteoclasts formed?

Answer 1

By the fusion of multiple bone marrow-derived monocytes

Question 2

In areas of bone undergoing resorption where do osteoclasts lie?

Answer 2

resorption lacunae (Howship lacunae)

Question 3

What is the part of the osteoclast in direct contact with bone called?

Answer 3

The ruffled border

Question 4

What does the membrane domain of osteoclasts form to resorb bone?

Answer 4

A circular sealing zone and the ruffled border

Question 5

How do osteoclasts promote bone resorption?

Answer 5

By pumping protons to acidify and promote the dissolution of hydroxyapatite and releasing hydrolytic enzymes for localized digestion of matrix proteins

Question 6

What covers the outside surface of bone?

Answer 6

The periosteum except in areas where bones articulate which are covered by cartilage

Question 7

What is the structure of the periosteum?

Answer 7

An outer fibrous layer resembling dense connective tissue and an inner more cellular layer containing osteoprogenitor cells

Question 8

What are Sharpey’s fibers?

Answer 8

Collagen fibers that connect the periosteum to the bone

Question 9

What does the endosteum cover?

Answer 9

The marrow cavity and the small trabeculae of bony matrix that project into the marrow cavities

Question 10

What does the endosteum contain?

Answer 10

Osteoprogenitor cells osteoblasts and bone lining cells within a sparse delicate matrix of collagen fibers