Chapter 6

Question 1

Functions of Skeletal System

Answer 1

• Support
• Protection
• Movement
• Storage
• Hematopoiesis

Question 2

Support of Skeletal System

Answer 2

-Provides a framework for the body

Question 3

Protection from Skeletal System

Answer 3

-Protects internal organs

Question 4

Movement of Skeletal System

Answer 4

-Skeletal muscles attach to bones to move body parts

Question 5

Storage of Skeletal System

Answer 5

Stores:

• Calcium (98%)
• Fat (Triglycerides)

Question 6

Hematopoiesis

Answer 6

-Production of blood cells (RBCs and WBCs) by hematopoietic stem cells (hematocytoblasts)

Question 7

Characterization of bone shape

Answer 7

• Long bone (Humerus)
• Short bone (Triquetral)
• Flat bone (Sternum)
• Irregular bone (Vertebra)

Question 8

Composition of Bone Matrix

Answer 8

-67% hydroxyapatites
Calcium Phosphate
Calcium Carbonate
-33% Collagen

Question 9

Hydroxyapatites

Answer 9

• Mineral Salts
• Inorganic
• Resist Compression

Question 10

Collagen

Answer 10

• Organic

- Resist tension

Question 11

Osteogenesis Imprefecta

Answer 11

-Caused by mutation in gene for Type I collagen

Question 12

What cells make up bone?

Answer 12

• Osteogenic cells —>
• Osteoblast —>
• Osteoclast —>
• Osteocytes

Question 13

Osteogenic Cell

Answer 13

• Mitotically active

- Stem cells

Question 14

Osteoblast

Answer 14

• Bone forming cells
• Secrete bone matrix
• Collagen and Osteoid

Question 15

Osteoid

Answer 15

• Immature bone matrix

- Glue that will hold calcium crystals and collagen fibers

Question 16

Osteoclast

Answer 16

• Giant multinucleate cells derived from stem cells in bone marrow
• Degrade bone matrix
• Ruffled border
• Increases surface area for degrading bone matrix

Question 17

How do osteoclasts degrade bone matrix?

Answer 17

• HCl degrades hydroxyapatites

- Lysosomal enzymes degrade collagen

Question 18

Osteocytes

Answer 18

• Reside in lacuna
• Monitor their environment
• Maintain bone matrix by regulating osteoblasts and osteoclasts

Question 19

Structure of bone

Answer 19

• Spongy bone
• Compact bone
• Articular cartilage

Question 20

Trabeculae

Answer 20

-Network of supporting “beams” present in spongy bone

Question 21

Long Bone Anatomy

Answer 21

• Diaphysis
• Epiphysis
• Periosteum
• Endosteum

Question 22

Diaphysis

Answer 22

-Shaft
-Compact bone-dense
-Medullary cavity
Yellow marrow-adipose
Red Marrow-hematopoiesis

Question 23

Epiphysis

Answer 23

• Ends of bone
• Compact bone-outer layer
• Spongy bone-porous
• Epiphyseal line
• Articular cartilage

Question 24

Epiphyseal line

Answer 24

-Former growth plate

Question 25

Articular Cartilage

Answer 25

- Cartilage at ends of bones - Made of hyaline - No nerves - Smooth - Enables bones to glide

Question 26

Periosteum

Answer 26

-Fibrous tissue coating outer surface of bones

Question 27

Outer Layer Composition of Periosteum

Answer 27

- Dense Irregular tissue - Surface for muscle attachment - Vascular

Question 28

Inner Layer Composition of Periosteum

Answer 28

-Contains osteogenic cells

Question 29

Sharpey's fibers

Answer 29

- Collagen fibers | - Attach periosteum to bone

Question 30

Endosteum

Answer 30

- Lines medullary cavity | - Contains Osteogenic cells

Question 31

Types of Bone Marrow

Answer 31

- Yellow Bone Marrow | - Red Bone Marrow

Question 32

Yellow Bone Marrow

Answer 32

-Fat Storage

Question 33

Red Bone Marrow

Answer 33

-Site of production for blood cells -Contains hematopoietic stem cells -These cells have the potential to differentiate into: WBCs RBCs Platelets

Question 34

Hematopoiesis

Answer 34

-The process by which hematopoietic stem cells self-renew and differentiate to form RBCs, WBCs, and platelets

Question 35

Where is hematopoietic tissue located in newborns?

Answer 35

-Medullary cavity of long bones and all areas of spongy bone that contains red marrow

Question 36

Where is hematopoeitic tissue located in adults?

Answer 36

-Most red marrow is replaced with yellow marrow except in: head of femur head of humerus Diploe of flat bones (Sternum, coxal bones)

Question 37

Osteons

Answer 37

-Unit of compact bone -Contains: Central Canal Lamella Lacuna

Question 38

Central Canal of Osteons

Answer 38

- Blood Vessels | - Nerve fibers

Question 39

Lamella of Osteons

Answer 39

-Rings around central canal

Question 40

Lacuna

Answer 40

-Where the osteocytes sit

Question 41

How is bone made?

Answer 41

- Intramembranous Ossification | - Endochondrial Ossification

Question 42

Intramembranous Ossification

Answer 42

- Differentiation of bone from mesenchymal stem cells found in fibrous connective tissue - Process by which cranial bones and clavicles are formed - Begins at 8 weeks of development-fibrous connective tissue starts to ossify

Question 43

Endochondrial Ossification

Answer 43

-Process by which cartilage is turned into bone

Question 44

Intramembranous ossification step 1

Answer 44

- Mesenchymal cells differentiate into osteoblasts | - Osteoblasts start laying down matrix (collagen, osteoid) to form ossification centers

Question 45

Intramembranous Ossification step 2

Answer 45

- Osteoids calcify forming the bone matrix | - Trapped osteoblasts turn into osteocytes

Question 46

Intramembranous Ossification step 3

Answer 46

- Trabeculae and periosteum form - Osteoid is laid down between embryonic blood vessels forming trabeculae - Vasculized mesenchyme condenses and becomes the periosteum

Question 47

Intramembranous Ossification step 4

Answer 47

- Trabeculae deep to periosteum are replaced by compact bone-forming compact bone plates - Spongey bone (diploe) persists inside