bone structure

Question 1

How many bones are in the human adult skeleton?

Answer 1

206

Question 2

What are the two groups of bones based on location?

Answer 2

• Axial
• Appendicular

Question 3

Name the components of the axial skeleton.

Answer 3

• Skull
• Vertebral column
• Rib cage

Question 4

Name the components of the appendicular skeleton.

Answer 4

• Upper limbs
• Lower limbs
• Shoulder girdle
• Hip girdle

Question 5

What are the four classifications of bones by shape?

Answer 5

• Long
• Short
• Flat
• Irregular

Question 6

Define long bones.

Answer 6

Bones longer than wide

Question 7

Give two examples of long bones.

Answer 7

• Thigh
• Forearm

Question 8

Define flat bones.

Answer 8

Thin, flattened, and usually a bit curved bones

Question 9

Give two examples of flat bones.

Answer 9

• Cranial bones
• Sternum

Question 10

Define short bones.

Answer 10

Almost cube-shaped bones

Question 11

Give two examples of short bones.

Answer 11

• Wrist bones
• Ankle bones

Question 12

What are sesamoid bones?

Answer 12

A special type of short bone that forms in a tendon

Question 13

Give an example of a sesamoid bone.

Answer 13

Patella

Question 14

Define irregular bones.

Answer 14

Bones with irregular shapes that fit none of the preceding classes

Question 15

Give two examples of irregular bones.

Answer 15

• Vertebrae
• Hip bones

Question 16

What is compact bone?

Answer 16

The outer layer of every bone (80%)

Question 17

What is spongy bone?

Answer 17

The inner trabeculated layer that usually contains marrow (20%)

Question 18

What is the diaphysis of a long bone?

Answer 18

The shaft of the bone

Question 19

What is the medullary cavity?

Answer 19

The central hollow space of a long bone

Question 20

What is the epiphysis?

Answer 20

The terminal portion of a long bone

Question 21

What is articular hyaline cartilage?

Answer 21

Cartilage situated at a joint

Question 22

What is the metaphysis?

Answer 22

The flared portion of the bone where diaphysis and epiphysis meet

Question 23

What is the periosteum?

Answer 23

The outer covering of a bone

Question 24

What are the two layers of the periosteum?

Answer 24

• Outer fibrous layer
• Inner osteogenic layer

Question 25

What is the endosteum?

Answer 25

The delicate connective covering of trabeculae or canals inside a bone

Question 26

What is red marrow?

Answer 26

Haematopoietic tissue located in certain bones

Question 27

What is yellow marrow?

Answer 27

Fat storage tissue primarily found in adults

Question 28

Where is red marrow located in adults?

Answer 28

* Flat bones of the skull * Sternum * Ribs * Clavicles * Scapulae * Hip bones * Vertebrae * Head of femur * Head of humerus

Question 29

What is the composition of the bone matrix?

Answer 29

* 10-20% water * 60-70% crystallized mineral salts * Mostly collagen

Question 30

What are osteogenic cells?

Answer 30

Cells found in periosteum and endosteum that develop into osteoblasts

Question 31

What do osteoblasts do?

Answer 31

Secrete unmineralized matrix (osteoid)

Question 32

What are osteocytes?

Answer 32

Mature bone cells that monitor and maintain bone

Question 33

What are osteoclasts?

Answer 33

Cells that digest bone matrix for normal bone turnover

Question 34

What is the structural unit of compact bone?

Answer 34

Osteons (Haversian system)

Question 35

What is the central canal in osteons?

Answer 35

Contains blood vessels, nerves, and lymphatics

Question 36

What are canaliculi?

Answer 36

Little canals that allow nutrient flow from canals and between osteocytes

Question 37

What are Volkmann’s canals?

Answer 37

Canals that run at right angles to the shaft, completing the communication pathway from the outside of the bone to its interior

Question 38

List the functions of bones.

Answer 38

* Support * Protection * Leverage for motion * Mineral homeostasis * Blood cell production * Triglyceride storage * Hormone production

Question 39

What is osteocalcin?

Answer 39

A hormone produced by bone tissue