Chapter 6 (Skeletal System)

Question 1

What are the 5 major functions of the skeletal system?

Answer 1

1. Support provides attachment of tissue and cradles organs
2. Storage of minerals (calcium, potassium) and lipids (yellow bone marrow)
3. Blood cell production (RBC, WBC, and platelets)
4. Protection of organs (ribs protect the heart)
5. Movement leveraging and lifting system 

Question 2

2 types of bone classification

Answer 2

1. Shape
2. Formation

Question 3

Define Long bone

Answer 3

Has a shaft plus two ends
Ex: humorous, femur, fingers and toes

Question 4

Define short bone

Answer 4

Cube shaped bones
Ex: carpal bones, tarsal bones

Question 5

Define flat bone

Answer 5

Flat
Ex: parietal bones, sternum, ribs and scapula

Question 6

Define irregular bone

Answer 6

Ex. Vertebrae and pelvis

Question 7

Define Sutural bone

Answer 7

Also called wormain bones, sutural bones, or sutures

Question 8

Define Sesamoid bone

Answer 8

Patella “sesame seed” develope in side tendon
Ex: found in knees, hands and feet

Question 9

Bone growth layers

Answer 9

Epiphysis
Metaphysis

Diaphysis

Metaphysis
Epiphysis

Question 10

Define Diaphysis

Answer 10

Extended tubular shaft; has 3 layers

Question 11

Define Metaphysis

Answer 11

Where diaphysis connects to epiphysis

Question 12

Define Epiphysis

Answer 12

Expanded area at each end of long bone; consists primarily of “spongy bone” with covering of compact bone called “cortex”
- where you get your growth from

Question 13

Define periosteum

Answer 13

Outer wrapping of bone made up of collagen fibers; has nerve and blood vessels; during bone growth will contain osteoblast and osteoclasts

Question 14

Define Compact bone

Answer 14

Middle layer; dense layer which provides strength against stress from sides or angles

Forms protective outer layer; always located on surface of bone

Question 15

Define marrow cavity (medullary cavity)

Answer 15

Inner layer that contains blood cell forming tissue (red marrow) or lipid/fat storing marrow (yellow marrow)

Question 16

Define Epiphyseal cartilages and lines

Answer 16

• where osteoblast are & where bone is built
• also called growth plates

Question 17

2 types of bone structure

Answer 17

1. Compact or dense bone
2. Spongy bone

Question 18

Define spongy bone (cancellous)

Answer 18

• Soft, forms open network; makes up the interior part of the bone
• support epiphysis if the bone
• not arranged in osteons (concentric circles)
• no capillaries or veins,nutrients reAches each cell by Canaliculi
• located in low stress areas
• is lighter so makes bone lighter and easier to move

Question 19

Structure of compact bone

Answer 19

• made up of haversian systems; thickest at areas where stressed are coming from (top and bottom)

-osteon: (haversian system) several “concentric circles” or lamellae; Thai structure provided strength

• lacunae: small outer wrap or compartment around osteocyte
• lamellae: one concentric circle which is formed around the bone
• Central canal: hole that provides blood vessels and nerves

Canaliculi: “little canals” which radiate out from the central Canal like spokes on a wheel, which provides for nutrients and waste exchange

Question 20

Function of periosteum

Answer 20

1. Isolates bone from surrounding tissue
2. Provides route for vessels and nerves to grow/attach
3. Assists in bone repair

Question 21

Define endosteum

Answer 21

Incomplete cellular layer that lines the marrow cavity in spongy bone; consists of a layer of osteoprogenitor cells that covers the bone matrix. If this cellular layer is not complete and matrix is exposed, osteoblasts and osteoclasts can remodel at those exposed points

Question 22

Define Yellow bone marrow

Answer 22

Dominated by fat cells; great energy reserve (lipids)

Question 23

Define red bone marrow

Answer 23

Mixture of mature and immature RBC, WBC and the stem cells that produce them; make blood cells

Question 24

Define Osteocytes (osteon)

Answer 24

Most common, mature occupies a lacuna “pocket” between layers. The layers are called lamellae aka concentric circles
- cannot divide
-Canaliculi are narrow passageways providing nutrients
- on rare occasions can develope back into osteoblasts if no lacunae are present

Question 25

Define Osteoblasts

Answer 25

Produces new bone matrix in a process called osteogenesis (coverts osteoid to bone) - can differentiate into osteocytes during “dermal ossification”

Question 26

Define Osteoprogenitor cells (Messenchymal cells)

Answer 26

Stem cells that produce daughter cells that become osteoblasts - cells that repair broken bone

Question 27

Define osteoclasts

Answer 27

-remove bone matrix - large cells with 50 nuclei -erode bone by process called osteolysis -regulates the amount of calcium in blood stream - use acids to destroy/breakdown minerals in bone - can phagocytize dead osteocytes in bone

Question 28

Bone growth when it stops and starts

Answer 28

- starts 6 weeks after fertilization and stops growing around age 25

Question 29

Define ossification

Answer 29

Replacing other tissues with bone

Question 30

Define Calcification

Answer 30

Deposits of calcium salts can occur in ossification and other tissues

Question 31

2 types of bone formation

Answer 31

1. Intramembranous or dermal bones- bones which are formed inside of a collagen membrane Ex: frontal and parietal bones 2. Endochondral bones- tissue is initially formed in hyaline cartilage then becomes bones Ex: vertebrae and long bones