BS: Bone Development

Question 1

Bone tissue formation, also known as…

Answer 1

osteogenesis/ossification

Question 2

When does formation of the skeleton begin? When does bone growth stop? When does bone remodeling stop?

Answer 2

2 months of development

adulthood (25)

lifelong

Question 3

Endochondral bone starts from….

Answer 3

cartilage

Question 4

Why is cartilage beneficial for the precursor of endochondral bone?

Answer 4

cartilage can accomodate mitosis

Question 5

Endochondral ossification:

Answer 5

bone formation by replacing cartilage

Question 6

Intramembranous ossification:

Answer 6

bone formation from fibrous membrane

Question 7

T/F– There is more membrane bone that endochondral.

Answer 7

false, there is more endochondral

Question 8

After complete endochondral ossification, where does hyaline cartilage remain?

Answer 8

at the articular cartilage point (ends of bone) and the epiphyseal plate

Question 9

What are the 5 main steps of ossification?

Answer 9

1. bone collar forms around diaphysis
2. central cartilage in diaphysis calcifies, then develops cavities
3. periosteal bud (blood vessel) invades cavities, leading to formation of spongy bone
4. diaphysis elongates, and medullary cavity forms
5. epiphysis ossify

Question 10

Most bones formed via intramembranous ossification are […] bones.

Answer 10

flat

Question 11

Our hands came from what fish?

Answer 11

lungfish

Question 12

The lungfish evolved to form the […].

Answer 12

greererpeton (ancient lizard)

Question 13

Interstitial growth causes the bone to grow…

Answer 13

lengthwise

Question 14

Appositional growth causes the bone to increase …

Answer 14

thickness

Question 15

What are the 5 zones within the epiphyseal plate?

Answer 15

1. resting zone
2. proliferation (growth) zone
3. hypertrophic zone
4. calcification zone
5. ossification

Question 16

What happens during epiphyseal’s second zone?

Answer 16

growth zone– cartilage cells undergo mitosis

Question 17

What happens during epiphyseal’s third zone?

Answer 17

hypertrophic zone– older catilage cells enlarge

Question 18

What happens during epiphyseal’s fourth zone?

Answer 18

calcification zone– matrix calcifies (deteriorates), cartilage cells die, blood vessels invade

Question 19

Near adolescence, […] divide less often and the […] thins and is replace by […].

Answer 19

chondrocytes; epiphyseal line; bone

Question 20

Epiphyseal plate closure occurs when?

Answer 20

epiphysis and diaphysis fuse

Question 21

[…] initiate ossification of the bone.

Answer 21

osteoblasts

Question 22

Bone deposition adds…

Answer 22

a new matrix during bone remodeling

Question 23

How often is spongy and compact bone replace?

Answer 23

spongy– 3-4 years

compact– 10 years

Question 24

When there is an imbalance of calcium, what occurs? What cells are called to regain balance?

Answer 24

the parathyroid gland release a parathyroid hormone (PTH)

osteoclasts degrade bone matrix and release Ca into the blood

Question 25

Sustained high Ca levels can lead to the formation of...

Answer 25

kidney stones

Question 26

Hypocalcemia causes... Hypercalcemia causes...

Answer 26

hyperexcitability non-responsiveness

Question 27

What is the importance of Ca?

Answer 27

functions in numerous metabolic activities (muscle contraction and coagulation)

Question 28

Wolf's law states that bones...

Answer 28

grow/remodel in response to demands placed on them

Question 29

Bend of the bone is caused by...

Answer 29

off center stress

Question 30

Bending [...] one side and [...] the other.

Answer 30

compresses; stretches

Question 31

Why is bone hollow?

Answer 31

compression and tension cancel each other out at the center of the bone

Question 32

Where is the diaphysis is thickest?

Answer 32

bending stresses are the greatest

Question 33

Wolfs law can explain...

Answer 33

1. handedness 2. curved bones = buckling 3. trabeculae form trusses along lines of stress 4. weight lifters have thick muscle attachments 5. fetus and bedridden people are featureless bc no stress

Question 34

Repair involves what 4 stages?

Answer 34

1. hematoma formation 2. fibrocartilaginous callus formation 3. bony callus formation 4. bone remodeling

Question 35

Rickets results in [...], soft, [...] bones because bone ends are [...].

Answer 35

bowed; weak; enlarged

Question 36

What is the cause of Rickets?

Answer 36

vitamin D deficiency/insufficient dietary of Ca

Question 37

Osteoporosis is a group of diseases in which bone [...] exceeds [...].

Answer 37

resorption; deposit

Question 38

What happens to bone during osteoporosis?

Answer 38

matrix is normal BUT mass declines

Question 39

What bones are most susceptible to osteoporosis?

Answer 39

spongy bone of spine and neck of femur