Skeletal System

Question 1

mesenchyme forms _________ _________, which appear in week 5

Answer 1

chondrification centers

Question 2

produce cartilage material

Answer 2

chondroblasts

Question 3

forms bases for most of the skeleton

Answer 3

chondrification centers

Question 4

maintenance cells for hyaline cartilage

Answer 4

chondrocytes

Question 5

four jobs of bone

Answer 5

structural framework

protection of organs

attachment for muscle

storage for minerals

Question 6

shaft of long bone

Answer 6

diaphysis

Question 7

articular ends of long bone

Answer 7

epiphysis

Question 8

growth plate - cartilage, separates growing bones

Answer 8

epiphyseal plate

Question 9

between diaphysis and epiphysis

Answer 9

metaphysis

Question 10

anchored by Sharpey’s fibers and covers diaphysis

Answer 10

periosteum

Question 11

four kinds of bone

Answer 11

woven bone

lamellar bone

cortical (compact) bone

trabecular bone

Question 12

composed of lamellar bone arranged in osteons

has periosteal and endosteal surfaces

Answer 12

cortical (compact) bone

Question 13

type of bone present in medullary cavity and ends of long bones

Answer 13

trabecular (spongy) bone

Question 14

forms at sites of periosteal injury and is temporary

Answer 14

woven bone

Question 15

type of bone that contains lacunar osteocytes

Answer 15

lamellar bone

Question 16

provides tensile strength and flexibility in collagenous organic matrix

Answer 16

type I collagen

Question 17

_________ stimulates the glycoproteins in non-collagenous organic matrix

Answer 17

vitamin D

Question 18

non-mineralized bone matrix

Answer 18

osteoid

Question 19

gives bones hardness; storage site for calcium and phosphorus

Answer 19

hydroxyapatite

Question 20

bone forming cells

produce organic matrix by surrounding itself (osteoid)

have PTH receptors

Answer 20

osteoblasts

Question 21

mature bone cells

located in lacunae

radiate in all directions in canaliculi

Answer 21

osteocytes

Question 22

help regulate minute-to-minute Ca influx (2)

Answer 22

osteoblasts and osteocytes

Question 23

osteoclasts are derived from_________

Answer 23

monocytes

Question 24

places for resorption of bone; where osteoclasts sit

Answer 24

Howship’s lacuna

Question 25

bone removing cells (resorb bone); respond indirectly to PTH

Answer 25

osteoclasts

Question 26

why do concentric lamellae run perpendicular to each other?

Answer 26

creates strength

Question 27

another name for osteon

Answer 27

Haversian canal

Question 28

outermost boundary of osteon

Answer 28

cementing line

Question 29

bone forms within an accumulation of mesenchymal or fibrous tissue; no cartilage model

Answer 29

intramembranous ossification

Question 30

bone forms in a cartilage model; cartilage is removed and replaced by bone

Answer 30

endochondral ossification

Question 31

has 5 zones and provides longitudinal bone growth

Answer 31

epiphyseal plate

Question 32

5 zones of epiphyseal plate

Answer 32

resting zone/reserve cartilage proliferation hypertrophy and maturation calcification ossification

Question 33

Describe intramembranous ossification

Answer 33

mesenchyme condense and differentiate cells to form osteoblasts. osteoblasts deposit osteoid and get trapped to form osteocytes this process forms lamellae, which then from osteons

Question 34

Describe the primary center of endochondral ossification

Answer 34

appears in diaphysis and develops towards epiphysis matrix becomes calcified and perichondrium becomes periosteum **diaphysis is ossified by birth

Question 35

describe secondary centers of endochondral ossifiaction

Answer 35

appear in epiphysis during first few years of life

Question 36

when does epiphyseal plate become ossified?

Answer 36

when growth is complete | ~20 years

Question 37

on which side is cartilage replaced in length-wise bone growth?

Answer 37

diaphyseal side

Question 38

describe width-wise bone growth (and another name for it)

Answer 38

bone deposits at the periosteum and resorption at the endosteum aka appositional growth

Question 39

bone production + resorption to allow adaptation of skeleton occurs throughout life

Answer 39

remodeling

Question 40

what is Wolff's Law?

Answer 40

bone will remodel to accommodate the stress placed on it

Question 41

Factors stimulating bone production (3)

Answer 41

Growth hormone calcitonin (from parathyroid cells) Bone compression

Question 42

Factors stimulating bone resorption (2)

Answer 42

PTH Bone tension

Question 43

when do vertebrae begin developing

Answer 43

week 4

Question 44

what are sclerotomes

Answer 44

paired tissue from somites that begin to surround notochord (week 4 - vertebral development)

Question 45

cranial sclerotomes are _________ arranged | caudal sclerotomes are _________ arranged

Answer 45

loosely densely

Question 46

what is the centrum

Answer 46

beginning vertebral body

Question 47

what do sclerotomes form? (2)

Answer 47

IV discs | centrum

Question 48

when do chondrification centers appear in mesenchyme in vertebral development?

Answer 48

week 6

Question 49

extension of chondrification centers develop (2)

Answer 49

spinous processes transverse processes

Question 50

Vertebral development Week 12: At birth: At puberty:

Answer 50

week 12: primary ossification centers are present at birth: fusion of vertebral arch and centrum (caudal to cranial) At puberty: secondary ossification centers present in spinous, transverse, and body (2)

Question 51

what is hemivertebra

Answer 51

failure of 2 chondrification centers to unite leads to scoliosis

Question 52

what is the calvaria

Answer 52

skull cap

Question 53

what are fontanelles

Answer 53

6 fibrous areas that allow calvaria to undergo changes in shape during birth

Question 54

bone around brain

Answer 54

neurocranium

Question 55

3 bones at base of cranium that undergo endochondral ossification

Answer 55

occipital bone sphenoid ethmoid

Question 56

bones forming face

Answer 56

viscerocranium

Question 57

viscerocranium forms from ______

Answer 57

1st pharyngeal arch

Question 58

premature closure of cranial sutures - scaphocephaly (sagittal) - brachycephaly (coronal)

Answer 58

craniosynostosis

Question 59

appendicular development begins in week ___ and is regulated by ______ and patterning pathways

Answer 59

6 Hox genes

Question 60

which appears first? pectoral girdle and upper limbs pelvic girdle and lower limbs

Answer 60

pectoral girdle and upper limbs

Question 61

primary ossification centers of limb bones appear in week ___

Answer 61

12

Question 62

first bone to ossify

Answer 62

clavicle

Question 63

rate of ossification of this bone is used to predict gestational age

Answer 63

femur

Question 64

when do secondary ossification centers first appear

Answer 64

34 - 38 weeks

Question 65

affects endochondrial ossification and disrupts growth at epiphyseal plates in fetal growth

Answer 65

achondroplasia

Question 66

six steps of fracture healing

Answer 66

hematoma (1 hour) hematoma and bone necrosis (1-2 days) organization of hematoma - soft callus (1-2 weeks) early ossification (3-8 weeks) late ossification with remodeling - hard callus (2-8 months) healed and remodeled fracture (1-3 years)

Question 67

joint with greatest range of motion has cavity filled with fluid, surrounded by joint capsule bone surfaces lined by articular cartilage

Answer 67

synovial joint

Question 68

joint with minimal range of motion lacks a joint cavity

Answer 68

fibrous joint

Question 69

three types of fibrous joint

Answer 69

synostosis: interdigitating bone synchondrosis: hyaline cartilage syndesmosis: fibrous tissue/fibrous cartilage

Question 70

leads to epiphyseal plate chondrodystrophy (Rickets)

Answer 70

vitamin D deficiency

Question 71

deficiency of vitamin C affecting collagen production of bone matrix

Answer 71

scurvy

Question 72

accumulation of unmineralized osteoid

Answer 72

osteomalacia