Bone Strcture

Question 1

What are the two bone textures?

Answer 1

The external layer is the compact bone is the dense smooth outer layer

The internal layer is the spongy bone, a honeycomb or flat pieces called trabeculae

Question 2

Short, irregular and flat bones have share the simple structure, what is this structure?

Answer 2

Thin plates of spongy bone covered by compact bone

Question 3

The plates of spongy bone in short, irregular and flat bone are surrounded by what?
Because these bones are not cylindrical, what do they not have?
What do they contain in terms of marrow and cartilage?

Answer 3

Surrounded by membranes, the outside membrane being the periosteum and the inside membrane being the endosteum

They do not have epiphyses or shaft

They contain marrow between their trabeculae but no well defined bone cavity. Where they form movable joints, hyaline cartilage covers their surfaces

Question 4

What is the spongy bone called in flat bones?

Answer 4

Diploe

Question 5

Structure of a typical long bone?

Answer 5

Shaft, bone ends and membrane

Question 6

What is another name for the shaft?
Constructed of what type of bone
What is in the centre of the bone?
The thing that is the centre of the bone, contains what?

Answer 6

Diaphysis
Constructed of a thick compact bone
In the centre is the medullary cavity
In this medullary cavity is the yellow bone marrow

Question 7

What are the bone ends called?
What is structure in terms of bone texture for this area?
What cartilage covers the bone ends?

Answer 7

Ephiphyses
A layer of compact bone for the exterior with the interior being made of spongy bone
Articular cartilage (hyaline) covers the joint surface of the ephiphysis to absorb stress

Question 8

What is between the diaphysis and epiphysis and what is this remnant of ?

Answer 8

Ephipyseal line which is remnant of the ephiphyseal plate, a disc of hyaline cartilage that grows during childhood . Sometimes called the metaphysis

Question 9

What are the two major membranes involved in bones?

Answer 9

Periosteum and endosteum

Question 10

Periosteum

1) How many layers in this membrane?
2) Covers what surface of the bone?
3) The layers of this membrane are made of what?
4) The periosteum is richly supplied with what? How do these reach the marrow cavity?
5) How is the periosteum attached to the bone?

Answer 10

1) Double layered membrane
2) Covers the exterior of the bone except joint surfaces which has the hyaline cartilage
3) The outer fibrous layer of the membrane is a dense irregular connective tissue. The inner layer of the membrane is made of osteogenic cells.
4) Supplied with blood nerve vessels and passes through the shaft to enter the marrow cavity via nutrient foramina
5) Periosteum attached to the bone via perforating sharpeys fibers which are tufts of collagen fibres that extend from its fibrous outer layer into the bone matrix.

Question 11

The endosteum

1) Made of what tissue?
2) Covers what?
3) Contains what cells?

Answer 11

1) Made of delicate connective tissue
2) Covers internal bone surfaces, trabeculae of the spongy bone and lines canals
3) Osteogenic cells

Question 12

What is hematopoietic tissue?

Answer 12

Red marrow

Question 13

Where is red marrow found

Answer 13

Found within the trabeculae cavities of spongy bone of long bones and in the diploe of flat bones

Question 14

Bone markings serve as sites of what?

Answer 14

Muscle, ligament and tendon attachment as joint surfaces, or as conduits for blood vessels and nerves

Question 15

Bone projections indicate what?

Answer 15

Stresses created by muscles attached to and pulling on them or are modified surfaces where bones meet and form joints

Question 16

Cells of bone tissue, name the 4 cells?

Answer 16

Osteogenic cell
Osteocytes
Osteoblasts
Osteoclasts

Question 17

Bone cells are surrounded by what?

Answer 17

ECM of their making

Question 18

Osteogenic cells are also called what?

1) found where?
2) What type of cells in the growing bones
3) When osteogenic cells are stimulated, what do they differentiate into?

Answer 18

Also called osteoprogenitor cells, mitotically active stem cells

1) Found in the periosteum and endosteum
2) In growing bones they are flattened and squamous
3) Into osteoblasts or bone lining cells

Question 19

Osteoblasts

1) What does these cells do?
2) What do they secrete?
3) What do they play a role in?
4) When depositing bone matrix, what shape are these cells?
5) When the osteocytes are completely surrounded by matrix, what do they become?

Answer 19

1) These cells are the bone forming cells which secrete bone matrix.
Matrix synthesising cells responsible for bone growth
2) They secrete collagen and calcium binding proteins for the bone matrix
3) Matrix calcification
4) Cube shaped cells
5) They become osteocytes

Question 20

Osteocytes

1) what are these cells?
2) what do these cells monitor and maintain?
3) If these cells die, what happens to the surrounding matrix?
4) What function do these cells have?

Answer 20

1) Mature bone cells that occupy spaces
2) Monitor and maintain the bone matrix
3) The surrounding matrix is resorbed
4) Act as sensors and respond to mechanical stimuli such as bone loading, bone deformation and weightlessness

Question 21

Bone lining cells

1) are what shaped cells?
2) found where?
3) What are periosteal and endosteal cells?

Answer 21

1) Flat cells
2) Found on bone surfaces where bone remodelling
3) Bone lining cells on the external bone surface are also called periosteal cells. Bone lining cells on the internal bone surface are called endosteal cells

Question 22

Osteoclasts

1) Derived from where?
2) What type of nucleus
3) Located where?

Answer 22

1) Derived from the same hematopoietic stem cells that differentiate into macrophages
2) Multi nucleate
3) Located at sites of bone resorption