Bone Tissue: Lecture 12

Question 1

functions of the skeletal system

Answer 1

protection, mineral storage, acid-base homeostasis, RBC formation, fat storage, movement, support

Question 2

bone classifications by shape

Answer 2

long, short, flat, irregular, sesamoid, sutural (wormian)

Question 3

articular cartilage (long bones)

Answer 3

covers joint surfaces, ease of movement

Question 4

periosteum

Answer 4

outer dense irregular CT, inner osteogenic layer; collagen fibers extend into bone matrix as perforating (Sharpey’s) fibers

Question 5

nutrient foramina

Answer 5

minute holes in bone tissue that allow blood vessels to penetrate

Question 6

endosteum

Answer 6

reticular CT, lines marrow cavities and covers trabecular surfaces of spongy bone

Question 7

epiphyseal plate/line

Answer 7

hyaline cartilage, zone of bone elongation

Question 8

compact bone

Answer 8

dense, osseous tissue, encloses medullary cavity

Question 9

spongy (cancellous) bone

Answer 9

within ends of long bones and inner portion of short, flat, and irregular bones; contains bone marrow; always surrounded by compact bone

Question 10

diploe

Answer 10

layer of spongy bone sandwiched between 2 compact bone layers

Question 11

trabeculae

Answer 11

bony struts that make up spongy bone, lined with endosteum

Question 12

red marrow

Answer 12

hematopoietic cells produce blood cells

Question 13

yellow marrow

Answer 13

stores triglycerides in adults

Question 14

osseous tissue

Answer 14

cells and ECM that make up bones

Question 15

osseous ECM

Answer 15

inorganic (65%)- Ca crystals, bicarbonate
organic (35%)- collagen fibers, proteoglycans, GAGs, glycoproteins

Question 16

major types of bone cells

Answer 16

osteogenic, osteoblasts, osteocytes, osteoclasts

Question 17

osteogenic cells

Answer 17

undifferentiated stem cells

Question 18

osteoblasts

Answer 18

build bone; secrete collagen fibers that form bone matrix, become osteocytes

Question 19

osteocytes

Answer 19

mature bone cells, trapped in lacunae

Question 20

osteoclasts

Answer 20

dissolve bone tissue when signaled, resorption; ruffled border

Question 21

osteon

Answer 21

structural unit of bone

Question 22

lamella

Answer 22

concentric, interstitial, circumferential
twist in opposite directions

Question 23

bone formation

Answer 23

intramembranous and endochondral ossification

Question 24

primary bone

Answer 24

immature or ‘woven’ bone; first bone formed in fetal development or bone repair

Question 25

secondary bone

Answer 25

mature or lamellar bone; composed of concentric or parallel lamellae; haversian canal system

Question 26

endochondral ossification

Answer 26

cartilage forms first, takes longer; important in formation of long bone, only first two years

Question 27

intramembranous ossification

Answer 27

bone is directly formed on mesenchyme, takes less time; stops at 18 in females, 21 in males

Question 28

osteoporosis

Answer 28

brittle bone disease due to inadequate inorganic matrix; low bone density

Question 29

longitudinal growth

Answer 29

increase in length by chondrocyte division in epiphyseal plates

Question 30

appositional growth

Answer 30

increase in width by osteoblasts underneath periosteum deposit new compact bone

Question 31

zone of ossification

Answer 31

osteoblasts deposit bone tissue, become entrapped osteocytes

Question 32

zone of cell calcification

Answer 32

dead, calcified chondrocytes

Question 33

zone of cell hypertrophy

Answer 33

mature, expanded chondroctes

Question 34

zone of cell proliferation

Answer 34

actively dividing chondrocytes

Question 35

zone of reserve hyaline cartilage

Answer 35

reserve chondroblasts

Question 36

hormones that affect bone growth

Answer 36

growth hormone, testosterone (appositional), estrogen (longitudinal)

Question 37

remodeling

Answer 37

continuous cycle of deposition and bone resorption for bone adaptation to sustained tension and stresses