Lecture 6: Bone Tissue - Microscopic Structure

Question 1

What does ossify mean?

Answer 1

To develop into bone or bony tissue (eg. from cartilage).

Question 2

Bone grows, can repair itself and ________.

Answer 2

Bone grows, can repair itself and REMODELS.

Question 3

What type of tissue is bone>

Answer 3

Connective tissue.

Question 4

What twoi components make up bone?

Answer 4

Organic and inorganic.

Question 5

How much of the bone matrix is organic?

Answer 5

33%

Question 6

How much of the bone matrix is inorganic?

Answer 6

67%

Question 7

What is the primary function of the organic component in bone?

Answer 7

To resist tension.

Question 8

What is the primary function of the inorganic component in bone?

Answer 8

To resist compression.

Question 9

The inorganic bone component is mostly made up of ________?

Answer 9

Hydroxyapatite (mineral salts)

Question 10

The organic bone component is mostly made up of ________ and __________?

Answer 10

Collagen (protein) and ground substance (proteoglycans).

Question 11

If the collagen is removed from a bone, what is the effect on its structure?

Answer 11

It will become very brittle and break easily.

Question 12

If the minerals (inorganic) are removed from a bone, what is the effect on its structure?

Answer 12

It will become very flexible and bend easily.

Question 13

What do osteoblasts do?

Answer 13

They build ECM

Question 14

What is an osteocyte?

Answer 14

A mature bone cell.

Question 15

What do osteoclasts do?

Answer 15

They break down ECM.

Question 16

What are foramina?

Answer 16

Small holes on the surface of compact bone,

Question 17

What is an osteon?

Answer 17

A longitudinal (lengthwise) unit within compact bone, consisting of lamellae, lacunae, canaliculi and the central canal.

Question 18

What are lamalla/e?

Answer 18

Tubes of ECM with collagen fibres aligned to resist forces. Series of concentric lammellae running longitudinally dow the shaft make up the osteon unit.

Question 19

What is the function of an osteon?

Answer 19

To maintain osteocytes by providing nutrients.

Question 20

What does the central canal consist of?

Answer 20

A blood vessel and nerves.

Question 21

What are laccunae?

Answer 21

“Lakes” for osteocytes. Small cavity in the bone.

Question 22

What are canaliculi?

Answer 22

Channels through the ECM for osteocytes.

Question 23

What is the periosteum?

Answer 23

A dense layer of vascular connective tissue enveloping the bones except at the surfaces of the joints.

Question 24

What is the subperiosteal surface of the bone?

Answer 24

The surface of the actual bone, beneath the periosteum.

Question 25

What are trabeculae?

Answer 25

Struts of lamella bone.

Question 26

What fills the cavities in cancellous bone?

Answer 26

Marrow

Question 27

Where are osteocytes housed in cancellous bone?

Answer 27

In the lacunae on the surfaces of the trabeculae.

Question 28

Trabeculae struts are arranged to follow the _____ __ _____.

Answer 28

Trabeculae struts are arranged to follow the LINES OF STRESS.

Question 29

What percentage of bone is living cells?

Answer 29

3%