Chapter 6

Question 1

What does the skeletal system contain?

Answer 1

Bones, cartilage, ligaments, other connective tissues relating to bones

Question 2

What are the categories of bones?

Answer 2

Sutural, irregular, short, long, sesamoid, flat

Question 3

What are sutural bones?

Answer 3

Small, flat, irregularly-shaped bones between the flat bones of the skull, individual variations between people

Question 4

What are irregular bones?

Answer 4

Bones with irregular shapes like the vertebrae

Question 5

What are short bones?

Answer 5

Boxy bones like the carpals and tarsals

Question 6

What are flat bones?

Answer 6

Bones that are thin with parallel surfaces like bones of the skull

Question 7

What are long bones?

Answer 7

Long bones are long and slender, like the femur

Question 8

What are sesamoid bones?

Answer 8

Small, round, flat bones like the patella, individual variations between people

Question 9

What are the three major types of bone markings?

Answer 9

Projections, openings, and depressions

Question 10

What do projections do?

Answer 10

Allow for attachment of muscles, tendons, and ligaments, and part of joint articulations

Question 11

What are openings and depressions?

Answer 11

Sites where blood vessels or nerves lie alongside or penetrate bones

Question 12

What is an example of a projection?

Answer 12

Ramus of the mandible, head of the femur

Question 13

What is an example of an opening?

Answer 13

Paranasal sinuses

Question 14

What is an example of a depression?

Answer 14

Coronoid fossa of the humerus

Question 15

What is the general structure of the long bone?

Answer 15

Diaphysis (shaft), Epiphysis (ends made mostly of spongy bone), and Metaphysis (narrow connective area)

Question 16

What is the general structure of a flat bone?

Answer 16

Core of spongy bone between two layers of compact bone

Question 17

What is bone tissue?

Answer 17

Supporting connective tissue

Question 18

What causes the density of the bone matrix?

Answer 18

Calcium salts and collagen fibers

Question 19

Where do osteocytes occur?

Answer 19

Lacunae

Question 20

What are canaliculi?

Answer 20

Narrow passageways that allow osteocytes to exchange nutrients and communicate

Question 21

What does the periosteum do?

Answer 21

Covers the outer surfaces of bones

Question 22

How much bone weight is calcium phosphate?

Answer 22

About 2/3 of bone weight

Question 23

How is hydroxyapatite made?

Answer 23

Calcium phosphate and calcium hydroxide interact and form crystals of it

Question 24

What is 1/3 of bone weight?

Answer 24

Collagen fibers

Question 25

What do collagen fibers do for hydroxyapatite crystals?

Answer 25

Provide a framework

Question 26

What are the four types of bone cells?

Answer 26

Osteogenic, osteoblasts, osteocytes, and osteoclasts

Question 27

What are osteogenic cells?

Answer 27

Mesenchymal stem cells that produce osteoblasts

Question 28

What are osteoblasts?

Answer 28

Immature bone cells

Question 29

What are osteocytes?

Answer 29

Mature bone cells

Question 30

How many osteocytes per lacuna?

Answer 30

Only one

Question 31

What are osteoclasts?

Answer 31

Large, multinucleate cells that absorb and remove bone matrix in osteolysis

Question 32

Where does osteolysis occur?

Answer 32

Osteoclastic crypts

Question 33

Are osteoclasts related to the other three types of bone cells?

Answer 33

No, they are basically a specialized type of macrophage

Question 34

What is the basic unit of compact bone?

Answer 34

Osteon

Question 35

What is the central canal of an osteon called?

Answer 35

Haversian canal

Question 36

What do haversian canals do?

Answer 36

Contains blood vessels that carry blood to and from the osteon

Question 37

What are perforating canals?

Answer 37

Perpendicular canals that also contain blood vessels for deep osteons and the medullary cavity

Question 38

What are the three types of lamellae?

Answer 38

Concentric, interstital, and circumferential

Question 39

What does concentric lamellae do?

Answer 39

Form osteons

Question 40

What does interstitial lamellae do?

Answer 40

Fill spaces in between osteons in compact bone

Question 41

What does circumferential lamellae do?

Answer 41

Occur at outer and inner bone surfaces

Question 42

What is different about spongy bone?

Answer 42

No osteons, no blood vessels, trabeculae matrix

Question 43

How does spongy bone get blood vessels?

Answer 43

Red bone marrow with diffusion and cannaliculi

Question 44

In some parts of the body, spongy bone contains what, and why?

Answer 44

Yellow bone marrow, energy reserve for adipose tissue

Question 45

Where is yellow bone marrow found?

Answer 45

Some spongy bone and medullary cavities of long bones in adults

Question 46

What do medullary cavities contain in children?

Answer 46

Red bone marrow

Question 47

What is the endosteum?

Answer 47

Incomplete cellular layer that lines inner surfaces of bone that's active during bone growth, repair, and remodeling.

Question 48

What is the endosteum made of?

Answer 48

Flattened layer of osteogenic cells that covers bone matrix

Question 49

What is ossification?

Answer 49

Bone formation

Question 50

What is calcification?

Answer 50

Deposition of calcium salts during ossification

Question 51

What are the two ossification processes?

Answer 51

Endochondral and intramembranous

Question 52

What happens in endochondral ossification?

Answer 52

Bone replaces existing cartilage, occurs during fetal development

Question 53

Is the timing of epiphyseal closures the same?

Answer 53

No. Toes may complete ossification around age 11, while the wrist may not complete until around age 25

Question 54

What is appositional growth?

Answer 54

How wide bones grow

Question 55

What is intramembranous ossification?

Answer 55

Bone develops directly from mesenchymal cells, occurs during fetal development, occurs mostly in flat bones

Question 56

What are spicules?

Answer 56

Bone grown in small struts