UNIT 2 - Compact/ Spongy Bones

Question 1

compact bone tissue is arranged in units called

Answer 1

osteons

Question 2

osteons are …

Answer 2

• aligned in the same direction along lines of stress

- changes over time in response to physical demands placed on skeleton

Question 3

Central (Haversian) canals

Answer 3

run longitudinally through the bone

Question 4

concentric lamellae

Answer 4

rings of hard calcified matrix, around canals

compact bone is often called lamellar bone

Question 5

Perforating (Volkmann’s) Canals

Answer 5

blood vessels, lymph vessels, and nerves from periosteum penetrate the compact bone

Question 6

The vessels and nerves of perforating canal connect with …

Answer 6

those of medullary cavity, periosteum, and central aversion canal

Question 7

lacunae

Answer 7

small spaces between lamellae - contain osteocytes

Question 8

canaliculi

Answer 8

hair like canals that radiate from lacunae in all directions & filled with extracellular fluid

Question 9

what does the canaliculi connect lacunae with?

Answer 9

other lacunae and with the central canals: providing many routes for blood-born nutrients, oxygen and cellular waste

Question 10

interstitial lamellae

Answer 10

fill in spaces between osteons in compact bone

*remnants of osteons whose matrix components have been almost completely recycled by osteoclasts

Question 11

circumferential lamellae

Answer 11

• found @ outer and inner surfaces of bone
• produced during growth of the bone
• covered by periosteum and endosteum

Question 12

Through the center of each osteon runs the _______

Answer 12

Central (Haversian) Canals

Question 13

Spongy bone doesn’t contain

Answer 13

osteons

Question 14

Osteogenesis (Ossification/Bone Growth)

Answer 14

• Process of bone tissue formation
• bone growth continues into early adulthood as we increase in size
• BONES CAN GROW IN THICKNESS THROUGHOUT LIFE
• Ossification in adults serves only for remodeling and repair of bones

Question 15

ossification

Answer 15

process of replacing other tissues with bone - term specifically refers to formation of bone

Question 16

The process of bone formation is called _____._____.____

Answer 16

Osteogenesis, Ossification, bone growth

Question 17

The process of bone destruction is known as ______

Answer 17

bone resorption

Question 18

calcification

Answer 18

deposition of calcium salts on soft tissues

Question 19

the skeleton of a human embryo is composed of

Answer 19

fibrous CT membranes OR pieces of hyaline cartilage that resemble bones

Question 20

Ossification can follow two patterns :

Answer 20

Endochondrial Ossification and Intramembranous ossification

Question 21

Endochondral ossification

Answer 21

formation of bone within hyaline cartilage
(–> mesenchymal cells are transformed into chondroblasts, which initially produced a hyaline cartilage model of bone
–> subsequently, osteoblasts gradually replace cartilage with bone)

Question 22

zone of resting cartilage

Answer 22

small scattered chondrocytes that anchor the epiphyseal plate to the bone of epiphysis (cells don’t function in bone growth)

Question 23

zone of proliferating cartilage (growth zone)

Answer 23

chondrocytes divided to replace those that die at the diaphyseal side of the epiphyseal plate

Question 24

zone of hypertrophic cartilage (transformation zone )

Answer 24

cell division in the zone of proliferating cartilage and maturation of the cells in the zone of hypertrophic cartilage
-responsible for lengthening of diaphysis

Question 25

zone of calcified cartilage (osteogenic zone)

Answer 25

-consists of mostly of dead chondrocytes (matrix around them has calcified)

Question 26

zone of ossification

Answer 26

osteoblasts replace the calcified cartilage by laying down bone matrix
-therefore, the diaphyseal border of the epiphyseal plate is firmly cemented to the bone of diaphysis