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Flashcards in Bone Deck (51):
1

Functions of bone (5)

Support

Protection

Levers for muscles

Reservoir for minerals (Ca2+ and P)

Houses marrow cavity which is responsible for hemopoiesis

2

Aceullar components of bone (2)

Inorganic

Organic

3

Inorganic component of bone

Ca2+ and P in the form of hydroxyapatite crystals (65% dry wt)

4

Organic component of bone

Almost exclusively Type I collagen (35% of dry wt)

5

Cellular components of bone (4)

Osteoprogenitor cells

Osteoblasts

Osteocytes

Osteoclasts

6

Where can you find osteoprogenitor cells

Located in periosteum, Haversian canals, and endosteum

7

Osteoblasts are derived from

osteoprogenitor cells

8

Osteoblasts function

Make/secrete osteoid (organic cmpd of ECM)

9

Osteocytes derived from

Osteoprogenitor cells

10

When osteoblasts become enveloped in osteoid they

Become osteocyte

11

Osteoclasts are derived from

monocyte/MQ

12

Osteoclasts are involved with

Resorption of bone (remodeling)

13

T/F Osteoclasts are motile

T

14

2 layers of periosteum

Outer dense fibrous CT layer

Inner cellular layer (where osteoprogenitor cells are)

15

Endosteum
-what is it
-what is it made of

Central cavity of bone with specialized thin CT layer

Made of osteoprogenitor cells and osteoblasts

16

Types of bone (2)

Woven (immature)

Lamellar (mature)

17

Woven bone (immature)-1sts

1st type of bone made during skeletal development and 1st type of bone to be laid down during fracture repair

18

Woven bone phenotype

Mottled appearance of matrix

Large osteocytes

Random orientation of cells

19

2 types of lemellar bone (mature)

Compact

Spongy (cancellous)

20

What system is observed in compact bone

Haversian system

21

What is the smallest functional bone unit

Osteon

22

Haversian canal contains

Blood vessels, nerves, endosteal cells

23

What are the vascular spaces that connect adjacent Haversian canals

Volkmann's canals

24

Fibrocartilage in intervertebral discs are caused by

FGF4 retrogene insert in chondrocytes to cause inappropriate activation of FGFR3

25

2 diff bone histogenesis

Endochondral ossification

Intramembranous ossification

26

Endochondral ossification process seen in what type of bones

Long (wt bearing) bones

27

Endochondral ossification requires

Hyaline cartilage template

28

Intramembranous ossification seen in what type of bones

Flat and short (non wt bearing) bones

29

Intramembranous ossification results in what for long bones

Thickening of long bones

30

Intramembranous ossification formation of bone directly from/within

Fibrous CT membranes

31

Origin of cartilage (3 steps)

Condensation of primordial mesenchymal cells

Mesenchymal cells differentiate into chondroblasts and exhibit interstitial growth as they are separated by their own secretory products

Periochondrium formed-hyaline cartilage model continues to grow by appositional and interstitial growth

32

T/F All long bones in an embryo start out as a hyaline cartilage template

T

33

T/F Bone replaces cartilage everywhere on bone

F

Except where there's a joint formation

34

T/F Growth in thickness of bones is only by interstitial growth

F

Appositional growth

35

Process of bones growing in thickness
-What differentiaties
-What forms

APPOSITIONAL GROWTH

Periosteal osteogenic cells differentiate into osteoblasts which secrete ECM

Ridges fuse and periosteum becomes endosteum

New concentric lamellae are formed

Osteoblasts under periosteum form new circumferential lamellae

36

Growth in length of bones incorporates

epiphyseal growth ( a results of cartilage growth)

37

Zones of growth in length (4) from earliest to latest

Zone of reserve cartilage
Zone of proliferation
Zone of maturation and hypertropy
Zone of calcification and ossification

38

3 phases of bone repair

Inflammatory
Reparative
Remodeling

39

Inflammatory phase of bone repair (2)

Hematoma formation

Ischemic necrosis of bone

40

Reparative phase of bone repair (3 stages)

Hematoma invaded by small capillaries to form granulation tissue then by osteoprogenitor cells forming a fibrocartilaginous callus and later bony callus
-->there's stabilization
-->size of callus related to amt of movement

Early woven bone formation and/or cartilage formation

Eventual replacement of cartilage with woven bone

41

Remodeling phase of bone repair (3 stages)

Woven bone replaced by lamellar bone

Bony callus reabsorbed

Repaired zone restored to original shape and strength

42

Red marrow vs yellow marrow

Red-hematopoietic cells (younger animals)
Yellow-adipose tissue (older animals)

43

The outer dense fibrous CT layer of periosteum contains (3)

fibroblasts

blood vessels

collagen

44

Osteoclasts lacunae

Howship's lacunae

45

How osteoclasts help with resorption (3)

Resorb bone via

Carbonic anhydrase-reabsorb inorganic cmpds (Ca2+, P)

Lysosomal enzymes and meralloproteinases- resorb organic cmpds

46

Endochondral ossification
What's the first bone tissue that appears?
How is it formed

Bone collar via intramembranous ossification

47

Endochondral ossification
what happens in the primary center of ossification (3)

1-Periochondrium becomes vascularized and becomes periosteum

2-Chondrogenic cells turn into osteoprogentor cells which turn into osteoblasts and secrete bone matrix forming bone collar

3-Chondrocytes in diaphysis die and form a cavity, Cavity is invaded by blood vessels and allows development of red marrow

48

Endochondral ossification
What happens at secondary center of ossification

-Osteoprogenitor cells invade cartilage of epiphysis and turn into osteoblasts that secrete bone matrix on cartilage model but NO BONE COLLAR MADE

49

What is different between secondary center of ossification and primary?

No bone collar made in secondary

Hyaline cartilage remains at surface (articular cartilage) and at growth plate at secondary.

50

Epiphyseal growth contributes to length or width of bone growth

Length

51

In intramembranous ossification, the portino of CT that does not undergo ossification...

Gives rise to endosteum and periosteum of intramembranous bone.