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Flashcards in Bone Deck (51)
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1
Q

Functions of bone (5)

A

Support

Protection

Levers for muscles

Reservoir for minerals (Ca2+ and P)

Houses marrow cavity which is responsible for hemopoiesis

2
Q

Aceullar components of bone (2)

A

Inorganic

Organic

3
Q

Inorganic component of bone

A

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

4
Q

Organic component of bone

A

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

5
Q

Cellular components of bone (4)

A

Osteoprogenitor cells

Osteoblasts

Osteocytes

Osteoclasts

6
Q

Where can you find osteoprogenitor cells

A

Located in periosteum, Haversian canals, and endosteum

7
Q

Osteoblasts are derived from

A

osteoprogenitor cells

8
Q

Osteoblasts function

A

Make/secrete osteoid (organic cmpd of ECM)

9
Q

Osteocytes derived from

A

Osteoprogenitor cells

10
Q

When osteoblasts become enveloped in osteoid they

A

Become osteocyte

11
Q

Osteoclasts are derived from

A

monocyte/MQ

12
Q

Osteoclasts are involved with

A

Resorption of bone (remodeling)

13
Q

T/F Osteoclasts are motile

A

T

14
Q

2 layers of periosteum

A

Outer dense fibrous CT layer

Inner cellular layer (where osteoprogenitor cells are)

15
Q

Endosteum

  • what is it
  • what is it made of
A

Central cavity of bone with specialized thin CT layer

Made of osteoprogenitor cells and osteoblasts

16
Q

Types of bone (2)

A

Woven (immature)

Lamellar (mature)

17
Q

Woven bone (immature)-1sts

A

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

18
Q

Woven bone phenotype

A

Mottled appearance of matrix

Large osteocytes

Random orientation of cells

19
Q

2 types of lemellar bone (mature)

A

Compact

Spongy (cancellous)

20
Q

What system is observed in compact bone

A

Haversian system

21
Q

What is the smallest functional bone unit

A

Osteon

22
Q

Haversian canal contains

A

Blood vessels, nerves, endosteal cells

23
Q

What are the vascular spaces that connect adjacent Haversian canals

A

Volkmann’s canals

24
Q

Fibrocartilage in intervertebral discs are caused by

A

FGF4 retrogene insert in chondrocytes to cause inappropriate activation of FGFR3

25
Q

2 diff bone histogenesis

A

Endochondral ossification

Intramembranous ossification

26
Q

Endochondral ossification process seen in what type of bones

A

Long (wt bearing) bones

27
Q

Endochondral ossification requires

A

Hyaline cartilage template

28
Q

Intramembranous ossification seen in what type of bones

A

Flat and short (non wt bearing) bones

29
Q

Intramembranous ossification results in what for long bones

A

Thickening of long bones

30
Q

Intramembranous ossification formation of bone directly from/within

A

Fibrous CT membranes

31
Q

Origin of cartilage (3 steps)

A

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
Q

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

A

T

33
Q

T/F Bone replaces cartilage everywhere on bone

A

F

Except where there’s a joint formation

34
Q

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

A

F

Appositional growth

35
Q

Process of bones growing in thickness

  • What differentiaties
  • What forms
A

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
Q

Growth in length of bones incorporates

A

epiphyseal growth ( a results of cartilage growth)

37
Q

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

A

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

38
Q

3 phases of bone repair

A

Inflammatory
Reparative
Remodeling

39
Q

Inflammatory phase of bone repair (2)

A

Hematoma formation

Ischemic necrosis of bone

40
Q

Reparative phase of bone repair (3 stages)

A

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
Q

Remodeling phase of bone repair (3 stages)

A

Woven bone replaced by lamellar bone

Bony callus reabsorbed

Repaired zone restored to original shape and strength

42
Q

Red marrow vs yellow marrow

A

Red-hematopoietic cells (younger animals)

Yellow-adipose tissue (older animals)

43
Q

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

A

fibroblasts

blood vessels

collagen

44
Q

Osteoclasts lacunae

A

Howship’s lacunae

45
Q

How osteoclasts help with resorption (3)

A

Resorb bone via

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

Lysosomal enzymes and meralloproteinases- resorb organic cmpds

46
Q

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

A

Bone collar via intramembranous ossification

47
Q

Endochondral ossification

what happens in the primary center of ossification (3)

A

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
Q

Endochondral ossification

What happens at secondary center of ossification

A

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

49
Q

What is different between secondary center of ossification and primary?

A

No bone collar made in secondary

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

50
Q

Epiphyseal growth contributes to length or width of bone growth

A

Length

51
Q

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

A

Gives rise to endosteum and periosteum of intramembranous bone.