Histology of Bone

Question 1

Functions of bone

Answer 1

protection
support
mechanical basis for movement
storage
hematopoiesis

Question 2

Bone classification based on shape

Answer 2

long
short
flat
irregular
sesamoid

Question 3

Long bones

Answer 3

longer than they are wide; upper and lower limbs

Question 4

Short bones

Answer 4

cubed in shape, carpals and tarsals

Question 5

Flat bones

Answer 5

plate-like; sternum and ribs

Question 6

Irregular bones

Answer 6

complex shape; vertebrae and hip bones

Question 7

Sesamoid bones

Answer 7

formed in tendons, act to alter pull of tendons; patella

Question 8

Gross observation of bone types

Answer 8

compact

spongy

Question 9

Structural components of long bones

Answer 9

Diaphysis/shaft
Metaphysis
Epiphysis

Question 10

Diaphysis

Answer 10

compact bone on outside, Medullary cavity for R or Y marrow

Question 11

Endosteum

Answer 11

cells belonging to stroma of marrow or derived from osteoblasts, very thin, osteoprogenator cells (osteoblasts), contains osteoclasts too

Question 12

Periosteum

Answer 12

covers outer surface of bone, vascularized and have osteoprogenator cells

Question 13

Metaphysis

Answer 13

area between diaphysis and epiphysis

Question 14

Epiphysis

Answer 14

contains articular surface of Hyaline cartilage

Question 15

Epiphyseal plate

Answer 15

in growing individuals, Hyaline cartilage activity lengthens long bones

Question 16

Epiphyseal line

Answer 16

in adults, solidified epiphyseal plate

Question 17

Perforating/Sharpey’s fibers

Answer 17

fibers that hold periosteum to bone surface with type I collagen

Question 18

Bone structure of short/flat/irregular/sesamoid

Answer 18

periosteum, compact bone, spongy bone (diploe), endosteum (lines trabeculae with R and Y marrow between)

Question 19

General composition of bone tissue

Answer 19

Cells

ECM

Question 20

Cells in bone tissue

Answer 20

osteogenic cells
osteoblasts
osteocytes
osteoclasts

Question 21

Osteogenic cells

Answer 21

like mesenchymal stem cells

Question 22

Osteoblasts

Answer 22

synthesize and secrete osteoid, activity signals calcification to occur

Question 23

Osteocytes

Answer 23

don’t lay matrix, stuck in matrix

Question 24

Osteoclasts

Answer 24

break down bone, formed by monocytes

Question 25

ECM in bone tissue

Answer 25

osteoid (organic), type I collagen and bone matrix proteins (GAGs, glycoproteins, osteoclasin (vitamin k dependent polypeptide, helps calcify matrix), osteonectin)

Question 26

Canaliculi

Answer 26

cytoplasmic extensions from osteocytes in lacunae, how nutrients are provided and waste is removed, connected via gap junctions

Question 27

Primary bone

Answer 27

also called woven or immature bone, formed during embryologic development or bone repair, contains lots of osteocytes, lower mineral content, temporary

Question 28

Secondary bone

Answer 28

also called lamellar or mature bone, highly organized, collagen fibers in layers, concentric circles with BVs in center, present in adults

Question 29

Osteons

Answer 29

also called Haversian systems, Haversian canal (containing n, v, and a), concentric lamellae made of bone ECM (collagen fibers run at 90 degrees from previous lamellae), outer collagen layer is called cement line

Question 30

Outer circumferential lamellae

Answer 30

lamellae encircling entire diaphysis

Question 31

Interstitial lamellae

Answer 31

old lamellae of older osteons

Question 32

Volkmann’s canal

Answer 32

also called perforating canal, connect Haversian canal to other osteon layers

Question 33

Osteon development

Answer 33

osteoclasts cut through bone to create space for new osteon, inward growing BV fills center of canal that is lines with osteoblasts that begin lying down new bone

Question 34

Regions of osteon development

Answer 34

cutting cone
reversal zone
closing cone

Question 35

Lamellar bone of spongy bone

Answer 35

does not contain osteons, trabeculae surrounds red marrow space