Ch 6 Bone

Question 1

Skeletal cartilage

Answer 1

water lends resiliency

no blood vessel or nerves

Question 2

perichondrium

Answer 2

surrounds skeletal cartilage
contains blood vessels for nutrient delivery
resist outward expansion

Question 3

type of skeletal cartilage

Answer 3

hyaline- support, flexibility, resilience
-collagen fiber only

elastic cartilage- similiar to hyaline but contains elastic fiber

fibrocartilage- thick collagen fiber, tensile strength

Question 4

Growth of cartilage

Answer 4

appositional growth- osteoprogenitor cells in perichondrium produce new layers of cartilage tissue from outside

Interstitual Growth- chondrocytes increase number of cells (mitosis) and amount of matrix from within

Question 5

Classification of bones

Answer 5

206 divided into 2:

Axial skeleton- long axis of body (skull, vertebral column, rib cage.)

Appendicular Skeleton- Bone of upper and lower limbs
(girdles attach limbs to axial skeleton)

Question 6

Classification by shape

Answer 6

Long bone- longer than wide
(limbs)

Short bones- Cube shaped(wrist , ankle)
sesamoid bone (tendon and patella)- vary in size and number if different people

flat bone- thin flat slightly curved(sternum, scapula, ribs, most of skull)

Irregular bone- complicated shape(vertebrae/ pelvic)

Question 7

7 Bone function

Answer 7

support-for body and soft organ

protection- brain, spinal cord, organ

movement- lever for muscle

mineral growth factor storage- calcium and phosphorus, growth factor reservoir

blood cell formation-hematopoiesis in red marrow

triglyceride(fat) storage- energy

Hormone production- osteocalcin- regulate bone formation

Question 8

bone tissues

Answer 8

bones contains: osseuos, nervous cartilage, fibrous, connective, muscle, epithelial

Question 9

bone level structure

Answer 9

gross, microscopic, chemical

Question 10

Gross bone anatomy

Answer 10

bone marking-projection, bulge, depression, fossa

Bone texture:

Compact(cortica)- dense outer layer, smooth and solid

Spongy(cancellous/trabecular)- honeycomb of flat pieces of bone

Periosteum- outer layer
endosteum- inner layer

Question 11

Anatomy of short, irregular, flat bone

Answer 11

thin plate of spongy bone covered by compact bone

no shaft or epiphyses

bone marrow throughout spongy bone, no marrow

Diploë- spongy bone tissue of the internal part.

hyaline cartilage covers articular surfaces

Question 12

Periosteum membrane

Answer 12

white double layered

covers external surface except joint

many nerve fiber and blood vesel

anchor tendon/ligament

sharpey’s fiber secure to bone matrix

Osetogenic contains prime stem cells

Question 13

Endosteum membrane

Answer 13

delicate connective tissue covering internal bone surface

covers trabeculae of spongy bone

Line canals that pass through compact bone

contains osteogenic cells

Question 14

Hematopoietic Tissue

Answer 14

Red marrow in trabecular cavity and diploë of spongy bone of irregular and flat bones, head of femur and humerus

Medullary Cavity- spongy bone of newborn,infant

adult long bone has less red marrow center than children

yellow marrow can convert to red if needed

Question 15

bone marking

projection, depression openings

Answer 15

site of muscle, ligament, tendon attachment on external surface

joint surface

conduit for blood vessel and nerve

Question 16

Microscopic Anatomy of bone

Answer 16

Specialized form of same basic cell

Osteogenic/osteoprogenitor/preosteoblast (stem cell)
Osteoblast
osteocyte
osteoclast

Osteoid- bone lining cell secreted by osetoblast

Question 17

osteogenic / Osteoprogenitor cells

Answer 17

mitotically active stem cells in periosteum and endosteum

differents to osteoblast or bone lining cells

Question 18

osteoblast

Answer 18

bone forming cells

bone mineralized by osteoblast

secret bone matrix or osteoid
-synthesize dense bone collage (90% of bone protein)

Question 19

osteoid cell

Answer 19

bone lining

flat cell on bone surface help maintain matrix

on external bone surface called periosteal cell

lining internal surface called endosteal cell

Question 20

osteoclast

Answer 20

derive from hematopoietic stem cell become macrophage

big multinucleated cell for bone resorption

ruffled border increase surface area for enzyme degradation

Question 21

osteocyte

Answer 21

mature bone cell in lacunae

monitor/maintain bone matrix

stress or strain sensors by responding and communicating mechanical stimuli to osteoblast and osteoclast for bone remodeling

Question 22

lamellae

Answer 22

interstitial lamellae- incomplete lamellae not part of complete osteon

fill gap between forming osteon

circumferential lamellae- deep to periosteum
superficial to endosteum
extend around diaphysis
resist twisting of long bone

Question 23

Microscopic spongy bone

cancellous bone

Answer 23

Poorly organized

Trabeculae- align along stress to resist it

no osteon

contain irregular arranged lamellae and oesteocyte interconnected by canaliculi

capillaries in endosteum supply nutrient

Question 24

Homeostatic imbalance

Answer 24

osteomalacia (adult)- bone poorly mineralized

not enough calcium salt

soft/weak bone/ painful

Rickets(children)- bow legged

bone abnormally large and long

vitamin D deficiency

Question 25

osteoporosis

Answer 25

bone resorption outpaces deposit

spongy bone of spine and neck of femur (common: vertebral and hip fracture)

Question 26

bone developement (ossification) 4 situation

Answer 26

• bone tissue formation
• formation of bony skeleton(2nd month developement)
• postnatal growth(until early adulthood)
• Bone remodeling and repair(lifelong)

Question 27

2 types of Ossification

Answer 27

endochondral- bone form by replacing hyaline cartilage
-forms most of skeleton

Intramembranous- bone develops from fibrous membrane formed by mesenchymal cells

• ossification center appear
• osteoid secreted
• woven bone and periosteum form
• lamellar bone replace woven bone
• (form flat bone)

Question 28

Postnatal bone growth

Answer 28

interstitial (longitudinal growth)
-increase length of lone bone

appositional growth- increase bone thickness

Question 29

Interstitial Growth

Answer 29

requires epiphyseal cartilage

epiphyseal plate maintain thickness

result 5 zone in cartilage:
Resting (quiescent)
Proliferation (growth)
Hypertrophic 
calcification
ossification

Question 30

Zones

Answer 30

Resting (Quiescent)- Cartilage on epiphyseal side of epiphyseal plate, inactive

Proliferation (growth)- cartilage on diaphysis side of epiphyseal plate
-rapidly divide pushing epiphysis away from diaphysis

Hypertrophic- Older chondrocyte closer to diaphysis and lacunae enlarge and erode

calcification- surround cartilage matrix calcifies, chondrocyte die

Ossification- Chondocyte deteriorate leaves calcified cartilage and epiphysis-diaphysis

• Spicule erode by osteoclast
• covered with new bone osteoblast
• replaced with spongy bone

Question 31

Epiphyseal plate closure

Answer 31

bone lengthen cease (require cartilage)

bone epiphysis and diaphysis fuze

f-18 m-21

Question 32

hormone regulation

Answer 32

GH- most important in epiphyseal plate activity in infancy

Thyroid- modulate activity of growth hormone
-ensure proper proportion

Testoserone(M)- promote adolescent growth spurt
-end growth by inducing epiphyseal plate

Question 33

Bone homeostasis- bone remodeling

Answer 33

consist of bone deposit and bone resorption

occur at surface of periosteum and endosteum

remodeling unit- adjacent osteoblast and osteoclast

Question 34

bone deposit

Answer 34

new matrix deposit by osteolast

Osteoid seam- unmineralized bone matrix

Calcification front- abrupt transition between osteoid and older mineralized bone

trigger not confirmed- mechanical signal involved

Question 35

bone resorption

Answer 35

function of osteoclast:

Depression or grooves break down matrix

Secrete lysosomal enzyme digest matrix and proton

acidity convert calcium salts to soluble form

phagocytize demineralized matrix and dead osteocyte

after resorption, osteoclast undergo apoptosis

Question 36

control remodeling

Answer 36

occurs continuously, regulated by genetic factor

negative feedback hormonal loop for calcium

response to mechanical and gravitational forces

Question 37

Calcium importance

Answer 37

function:
Nerve impulse transmission
muscle contraction
blood coagulation
secretion
cell division

Question 38

hormonal control of blood calcium

Answer 38

parathyroid hormone (PTH)
-remove calcium from bone regardless of integrity

calcithonin- produced by parafollicular cells of thyroid

Question 39

calcium homeostasis

Answer 39

calcium homeostasis of blood: 9-11 mg/100ml

Hyperexcitability- level too low
nonresponsiveness- level too high

hypercalcemia- high blood calcium levels
- deposit of calcium salt in blood vessel, kidney interfere with function

Question 40

Wolff’s Law

Answer 40

bone grow or remodel in response to demand

Reason for- handedness, thicker and stronger bone of that limb

curved bone thickest where most likely to buckle

trabeculae form trusses along stress lines

Question 41

fracture and bone repair

Answer 41

fracture-break in bone

Reactive phase- early inflammation

Reparative phase- formatijon of fibrocartilaginous callus

bone remodeling phase– last step as bone callus removed

Question 42

4 stage bone repair

Answer 42

hematoma formation

fibrocartilaginous callus formation

bony callus formation

bone remodeling

Question 43

fracture classification

Answer 43

position of bone end after fracture

• nondisplaced-end retain normal position
• displced- end out of normal ligament

completeness/break

• complete- broken all the way
• incomplete- not broken all the way

skin penetration-
open- skin penetrated
closed- skin not penetrated