Bone

Question 1

Functions of bone (5)

Answer 1

Support

Protection

Levers for muscles

Reservoir for minerals (Ca2+ and P)

Houses marrow cavity which is responsible for hemopoiesis

Question 2

Aceullar components of bone (2)

Answer 2

Inorganic

Organic

Question 3

Inorganic component of bone

Answer 3

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

Question 4

Organic component of bone

Answer 4

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

Question 5

Cellular components of bone (4)

Answer 5

Osteoprogenitor cells

Osteoblasts

Osteocytes

Osteoclasts

Question 6

Where can you find osteoprogenitor cells

Answer 6

Located in periosteum, Haversian canals, and endosteum

Question 7

Osteoblasts are derived from

Answer 7

osteoprogenitor cells

Question 8

Osteoblasts function

Answer 8

Make/secrete osteoid (organic cmpd of ECM)

Question 9

Osteocytes derived from

Answer 9

Osteoprogenitor cells

Question 10

When osteoblasts become enveloped in osteoid they

Answer 10

Become osteocyte

Question 11

Osteoclasts are derived from

Answer 11

monocyte/MQ

Question 12

Osteoclasts are involved with

Answer 12

Resorption of bone (remodeling)

Question 13

T/F Osteoclasts are motile

Answer 13

T

Question 14

2 layers of periosteum

Answer 14

Outer dense fibrous CT layer

Inner cellular layer (where osteoprogenitor cells are)

Question 15

Endosteum

• what is it
• what is it made of

Answer 15

Central cavity of bone with specialized thin CT layer

Made of osteoprogenitor cells and osteoblasts

Question 16

Types of bone (2)

Answer 16

Woven (immature)

Lamellar (mature)

Question 17

Woven bone (immature)-1sts

Answer 17

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

Question 18

Woven bone phenotype

Answer 18

Mottled appearance of matrix

Large osteocytes

Random orientation of cells

Question 19

2 types of lemellar bone (mature)

Answer 19

Compact

Spongy (cancellous)

Question 20

What system is observed in compact bone

Answer 20

Haversian system

Question 21

What is the smallest functional bone unit

Answer 21

Osteon

Question 22

Haversian canal contains

Answer 22

Blood vessels, nerves, endosteal cells

Question 23

What are the vascular spaces that connect adjacent Haversian canals

Answer 23

Volkmann’s canals

Question 24

Fibrocartilage in intervertebral discs are caused by

Answer 24

FGF4 retrogene insert in chondrocytes to cause inappropriate activation of FGFR3

Question 25

2 diff bone histogenesis

Answer 25

Endochondral ossification Intramembranous ossification

Question 26

Endochondral ossification process seen in what type of bones

Answer 26

Long (wt bearing) bones

Question 27

Endochondral ossification requires

Answer 27

Hyaline cartilage template

Question 28

Intramembranous ossification seen in what type of bones

Answer 28

Flat and short (non wt bearing) bones

Question 29

Intramembranous ossification results in what for long bones

Answer 29

Thickening of long bones

Question 30

Intramembranous ossification formation of bone directly from/within

Answer 30

Fibrous CT membranes

Question 31

Origin of cartilage (3 steps)

Answer 31

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

Question 32

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

Answer 32

T

Question 33

T/F Bone replaces cartilage everywhere on bone

Answer 33

F Except where there's a joint formation

Question 34

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

Answer 34

F Appositional growth

Question 35

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

Answer 35

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

Question 36

Growth in length of bones incorporates

Answer 36

epiphyseal growth ( a results of cartilage growth)

Question 37

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

Answer 37

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

Question 38

3 phases of bone repair

Answer 38

Inflammatory Reparative Remodeling

Question 39

Inflammatory phase of bone repair (2)

Answer 39

Hematoma formation Ischemic necrosis of bone

Question 40

Reparative phase of bone repair (3 stages)

Answer 40

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

Question 41

Remodeling phase of bone repair (3 stages)

Answer 41

Woven bone replaced by lamellar bone Bony callus reabsorbed Repaired zone restored to original shape and strength

Question 42

Red marrow vs yellow marrow

Answer 42

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

Question 43

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

Answer 43

fibroblasts blood vessels collagen

Question 44

Osteoclasts lacunae

Answer 44

Howship's lacunae

Question 45

How osteoclasts help with resorption (3)

Answer 45

Resorb bone via Carbonic anhydrase-reabsorb inorganic cmpds (Ca2+, P) Lysosomal enzymes and meralloproteinases- resorb organic cmpds

Question 46

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

Answer 46

Bone collar via intramembranous ossification

Question 47

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

Answer 47

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

Question 48

Endochondral ossification | What happens at secondary center of ossification

Answer 48

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

Question 49

What is different between secondary center of ossification and primary?

Answer 49

No bone collar made in secondary Hyaline cartilage remains at surface (articular cartilage) and at growth plate at secondary.

Question 50

Epiphyseal growth contributes to length or width of bone growth

Answer 50

Length

Question 51

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

Answer 51

Gives rise to endosteum and periosteum of intramembranous bone.