Exam 2: Bone

Question 1

osteoblast

Answer 1

actively secrete matrix in one direction

Question 2

osteocyte

Answer 2

trapped in matrix, cannot secrete
maintains matrix w/ mineralized calcium salts

Question 3

Osteocytes are derived from…

Answer 3

mesenchymal cells

Question 4

Ground substance in bone make-up

Answer 4

hydroxyapatite (mineral calcium salts)

Question 5

Function of matrix in bone

Answer 5

weight-baring, resists bending

Question 6

Compact bone

Answer 6

dense/cortical
thin, very strong

Question 7

Cancellous bone

Answer 7

spongy/medullary/trabecular
spaces w/ bone marrow inside

Question 8

Epiphysis

Answer 8

articular surface of bone (ends)
lined with hyaline cartilage

Question 9

Physis / Epiphyseal Plate

Answer 9

site of growth
grows in length

Question 10

Diaphysis

Answer 10

central part of bone
contains nutrient canal (brings in circulation)

Question 11

Two Types of Histological Bone Preps

Answer 11

Ground Bone
Decalcified Bone

Question 12

Ground Bone

Answer 12

dried | air trapped
osteons with lamellae and central canal
flattened lacunae | central vessels

Question 13

Decalcified Bone

Answer 13

fixed & demineralized
H&E stain
perforating canal (circulation between osteons)

Question 14

Canaliculi

Answer 14

canals with cell processes from one cell to another w/ gap junctions

Question 15

Canaliculi function

Answer 15

nutrition between cells (transmit via gap junctions)

Question 16

Lacunae

Answer 16

spaces in matrix that living cells occupy

Question 17

Periosteum

Answer 17

dense collagenous connective sheath

Question 18

Endosteum

Answer 18

inner lining of bone

Question 19

What is in between the periosteum & endosteum of bone

Answer 19

precipitate of calcium salts

Question 20

Lamellae

Answer 20

ring-like structures that make up osteon

Question 21

Circular/central lamellae

Answer 21

osteonal lamellae

Question 22

Periphery Lamellae

Answer 22

Outer circumferential

Question 23

Lamellae on inner surface of bone

Answer 23

inner circumferential

Question 24

old lamellae of prior osteons between osteons

Answer 24

interstitial lamellae

Question 25

How do lamellae form?

Answer 25

by collagen fibers running helically in various directions

Question 26

Osteogenesis

Answer 26

synthesizing new bone

Question 27

Osteogenesis Process

Answer 27

osteoblasts secrete procollagen --> tropocollagen --> collagen type I fibers = osteoid Osteoblasts secrete matrix vesicles --> mineralization = bone

Question 28

perforating canal

Answer 28

canal between two central canals of osteons

Question 29

cement line

Answer 29

lines outer edge of osteon no canaliculi and few collagen fibers

Question 30

osteoid

Answer 30

center of bone ossification (bone before its mature)

Question 31

trabeculae

Answer 31

bony spicules of osteoid which grow/radiate in many directions

Question 32

Intramembranous Ossification

Answer 32

new bone formation occurs in mesenchyme growth in width

Question 33

Erosion Lacunae

Answer 33

depressions in bone where osteoclasts reside

Question 34

Osteoclast

Answer 34

multinucleated cell which breaks down bone much larger than blasts/cytes

Question 35

What types of bone develop from intramembranous ossification?

Answer 35

flat bones (ex. skull)

Question 36

Endochondral Ossification

Answer 36

new bone formation at physis from hyaline cartilage growth in length

Question 37

What type of bones develop from endochondral ossification?

Answer 37

extremities, vertebral column, pelvis, base of skull

Question 38

Bony Collar

Answer 38

central section formed from endochondral ossification when capillary supply causes osteoblasts to form

Question 39

Where does bone grow in length?

Answer 39

physis (growth plate)

Question 40

Cutting Cone

Answer 40

portion of cone in bone remodeling with osteoclasts where old bone is broken down

Question 41

Reversal Zone

Answer 41

portion of bone remodeling where resorption (break down) is completed

Question 42

Closing Zone

Answer 42

portion of bone remodeling where osteoblasts produce lamellar bone and form osteon

Question 43

Woven bone

Answer 43

immature/primary bone newly calcified in developing bones

Question 44

Where is the primary center of ossification?

Answer 44

diaphysis

Question 45

What kind of growth occurs in bone?

Answer 45

Appositional growth NO interstitial (inflexible matrix)

Question 46

Lamellar Bone

Answer 46

secondary/mature bone lamellae present lots of calcification

Question 47

Ruffled Border

Answer 47

plasma membrane extensions of osteoclasts which increase SA

Question 48

How do osteoclasts break down bone?

Answer 48

pump H+ to dissolve hydroxyapatite (mineral) create lysosomes which break down protein

Question 49

Wolff's Law

Answer 49

bone develops structures most suited to resist forces acting upon it

Question 50

Callus

Answer 50

structure formed around broken ends of bone to immobilize it

Question 51

Purpose of External Fixation of bone

Answer 51

treatment of fracture that leads to rapid fracture repair

Question 52

Synarthroses

Answer 52

joint between bones connected by CT immobile

Question 53

Synostoses

Answer 53

bone to bone via bone tissue ex. sutures of adult skull

Question 54

Synchondroses

Answer 54

bone to bone via cartilage ex. epiphyseal plate | vertebrae-disc

Question 55

Syndesmoses

Answer 55

bone to bone via dense fibrous CT ex. sutures of young skull

Question 56

Diarthroses

Answer 56

moveable / synovial joints weight-baring have joint capsule

Question 57

Function of joint capsule

Answer 57

structural support

Question 58

Synovial Joint Layers

Answer 58

synovial membrane secretes synovial fluid (lubricant)

Question 59

Zone of Reserve

Answer 59

normal, resting hyaline cartilage

Question 60

Zone of Proliferation

Answer 60

rapid division of chrondocytes

Question 61

Zone of Hypertrophy

Answer 61

chondrocytes enlarge

Question 62

Zone of Calcification

Answer 62

cell death