Chapter 6

Question 1

Bone

Answer 1

Organ made up of Tissues (bone, cartilage, dense connective tissue, adipose, and nervous tissue) working together ~ no lymphatic vessels

Question 2

Skeletal system

Answer 2

entire framework of bones + their cartilages

Question 3

Functions of skeletal system

Answer 3

• 1. Provides support
• 2. Protects the internal organs (brain, heart, etc.)
• 3. Assists body movements (in conjunction with muscles)
• 4. Mineral homeostasis - stores and releases calcium + phosphorus
• 5. Participates in blood cell production (hemopoiesis)
• 6. Stores triglycerides in adipose cells of yellow marrow

Question 4

Diaphysis

Answer 4

Shaft

Question 5

Epiphyses

Answer 5

Both ends of bone made of hyaline cartilage

Question 6

Metaphyses

Answer 6

Between diaphysis and epiphysis containing a growth plate on each end: hyaline cartilage (children) bone (adults)

Question 7

Epiphyseal line

Answer 7

Remanent of the growth plate in adults - when the layer of hyaline cartilage “epiphyseal growth plate” is replaced by bone in adults

Question 8

Articular cartilage

Answer 8

thin layer of hyaline cartilage covering both epiphyses where the bone forms a joint

Question 9

Periosteum

Answer 9

dense irregular connective tissue surrounding diaphysis (where articular cartilage is absent) ~ Rich blood supply. Attaches to underlying bone via Sharpey’s fibers

Question 10

Inner Osteogenic layer

Answer 10

stem cells ~ enable bone to grow in thickness, not in length

Question 11

Outer Fibrous layer

Answer 11

dense irregular connective tissue

Question 12

Perforating (Sharpey’s) fibres

Answer 12

thick bundles of collagen; extend from periosteum into bone’s extracellular matrix

Question 13

Medullary (marrow) cavity

Answer 13

hollow space within diaphysis ; containing bone marrow (Yellow = adults / Red = infants) lightens the weight of bone

Question 14

Endosteum

Answer 14

thin membrane lining the medullary cavity (areolar connective tissue)

Question 15

Bone contains

Answer 15

abundant extracellular matrix ; surrounds widely separated cells

Question 16

Extracellular matrix

Answer 16

15% water , 30% collagen , 55% crystallized mineral salts

Question 17

Resorption

Answer 17

process of breaking down extracellular matrix of bone to release calcium into blood

Question 18

Remodelling

Answer 18

throughout life ; depositing calcium + phosphorus into matrix of bone

Question 19

4 cell types

Answer 19

Osteoprogenitor
Osteoblasts
Osteocytes
Osteoclasts

Question 20

Osteoprogenitor cells

Answer 20

• bone stem cells
• undergo cell division when stimulated
• Cells develop into osteoblasts (gap junctions)
- Formed from: Mesenchyme tissue
- Found in: Inner periosteum, endosteum, canals in bone with blood vessels

Question 21

Osteoblasts

Answer 21

BUILD BONE
• bone-building cells
• synthesize / secrete collagen fibers, forms bone extracellular matrix, deposits
calcium/phosphorus from food, initiate calcification
• cell secretes extracellular matrix
• Surrounded with matrix, trapped in their own secretions —> become osteocytes
- Formed from: Osteoprogenitor cells (gap junctions)
- Found in: Extracellular matrix, aligned along trabeculae of new bone

Question 22

Osteocytes

Answer 22

• Mature bone cells
• **Primary cells in bone tissue
• maintains bone tissue/metabolism; nutrient exchange in blood
- Formed from: Osteoprogenitor cells - Found in: Lacunae

Question 23

Osteoclasts

Answer 23

CARVE OUT BONE
• Large Cell; breaks down extracellular matrix
• Develops from white blood cells
• Remodels + bone Resorption ; calcium release
• Ruffled border — folded plasma membrane; secretes digestive enzymes to underlying extracellular matrix that dissolves, releasing calcium to blood
- Formed from: 5-50 fused Monocytes (WBC) ~ multiple nucleus’s - Found in: Endosteum

Question 24

Bone tissue types

Answer 24

Compact bone
Spongy bone

Question 25

Skeleton is made up of 80%

Answer 25

Compact bone

Question 26

Skeleton is made up of 20%

Answer 26

Spongy bone