23: Cartilage And Bone Tissue

Question 1

What % of cartilage is water?

Answer 1

60-80%

Question 2

Vascularization and innervation of cartilage

Answer 2

Avascular, not innervated

Question 3

How do nutrients and gases get into cartilage?

Answer 3

Diffusion

Question 4

Perichondrium composition

Answer 4

Dense irregular CT with two layers

Question 5

Outer and inner layer of perichondrium

Answer 5

Outer fibrous layer: type I collagen + fibroblasts

Inner chondrogenic layer: mesenchymal SCs for growth and maintenance

Question 6

Perichondrium function

Answer 6

Resists outer cartilage expansion when compressed

Question 7

Ground substance of cartilage (3 components)

Answer 7

Hyaluronic acid, proteoglycans, water

Question 8

ECM of cartilage: fibers

Answer 8

Type II collagen always, some have elastin or type I collagen

Question 9

How are bones considered organs

Answer 9

Contain all four tissue types

Question 10

Innervation and Vascularization of bone

Answer 10

Innervated + vascular

Question 11

Where are nerves found in bone?

Answer 11

Periosteum

Question 12

Five parts of a long bone

Answer 12

Epiphysis, diaphysis, metaphysis, periosteum, endosteum

Question 13

Epiphysis

Answer 13

Knobby regions at ends of long bone, with compact bone superficially and trabecular deep to the surface

Question 14

Diaphysis

Answer 14

Elongated shaft of long bone housing the marrow cavity

Question 15

Metaphysis

Answer 15

Spongy bone between diaphysis and epiphysis

Question 16

Periosteum tissue type

Answer 16

Dense irregular CT

Question 17

Endosteum

Answer 17

CT lining all trabeculae and the marrow cavity

Question 18

Cell types present in periosteum vs endosteum

Answer 18

Periosteum: osteoblasts, osteoprogenitors
Endosteum: osteoprogenitors, reticular cells of bone marrow

Question 19

Organic vs inorganic osteoid compositions

Answer 19

Organic: type I collagen, proteoglycans
Inorganic: calcium phosphate, hydroxyapatite crystals

Question 20

Two functions of long processes of osteocytes (found in canaliculi)

Answer 20

1. Communication with other cells via gap junctions

2. Receive nutrients

Question 21

Osteon

Answer 21

Concentric lamellae surrounding a central canal, running parallel to diaphysis

Question 22

Cement line

Answer 22

Outer boundary of an osteon

Question 23

Interstitial lamellae

Answer 23

Partial rings, remnants of previous concentric lamellae

Question 24

Five zones of epiphyseal growth plate growth and what happens in each

Answer 24

1. Resting zone: reserved chondrocytes
2. Proliferation zone: chondrocytes proliferate + stack up
3. Hypertrophic zone: older cartilage cells enlarge + secrete matrix
4. Calcification zone: calcification occurs and cartilage cells die
5. Ossification zone: where new bone forms

Question 25

How often is trabecular bone replaced vs compact bone?

Answer 25

Trabecular: every 3-4 years
Compact: every 10 years

Question 26

Two functions of bone remodeling

Answer 26

1. Repair microdamage

2. Calcium metabolism

Question 27

How much Ca can enter or leave the adult skeleton each day

Answer 27

500mg

Question 28

Achondroplasia

Answer 28

Most common form of dwarfism with shortened long bones, small midface, and altered spinal curvature

Question 29

Mutation in achondroplasia and genetic inheritance pattern

Answer 29

FGFR3 mutation; autosomal dominant

Question 30

What does FGFR3 play a role in?

Answer 30

Chondroblast proliferation

Question 31

Osteoporosis

Answer 31

Low bone mass due to bone resorption faster than deposition

Question 32

Why is estrogen therapy for women controversial?

Answer 32

Increased risk of MI, CVA, CA

Question 33

Vitamin D deficiency in adults vs children

Answer 33

Adults: osteomalacia
Children: rickets

Question 34

Osteomalacia

Answer 34

Soft bones due to inadequate mineralization

Question 35

Rickets

Answer 35

Weakened long bones, abnormal head and rib cage