Micro Bone

Front 1

True or false: Bone is a living, vital, responsive tissue

Back 1

True

Front 2

Like other connective tissue bone has what three components:

Back 2

cells, fibers, and ground substance

Front 3

Describe the organic matrix of bone:

Back 3

The fibers and ground substance are called the organic matrix, or osteoid. This is at first unmineralized. Bone becomes rigid due to the mineralization of its osteoid, and its cells become trapped

Front 4

Osteoblasts
produce:
located:
histology:

Back 4

produce-organic ECM
located- surface of bone tissue
hist: basophilic, cuboidal if active, somewhat flattened if inactive

Front 5

Osteocytes
f(x)-
location-
cell processes-

Back 5

f(x)- help maintian bone matrix and control mineral homeostasis
osteocytes - cells w/in bone lacunae
processes- gap junctions on their cell processes connect osteocytes

Front 6

Osteoclasts
f(x)-
location-
arrise from -
example-
histology-

Back 6

f(x)- remove bone
arrise from monocytes - multinucleated macrophages
example of a synchtium
histo- acidophili, ruffled border
location- next to Howship's lacunae in the bone surface

Front 7

osteoid definition
components

Back 7

the unmineralized organic matrix of bone
90% collagen fibers (acidophilic)
10% ground substance-containing some GAGs

Front 8

Bone is not rigid until the osteoid becomes mineralized by the deposition of the ______amongst the collagen lattice

Back 8

hydroxyapatitie crystals

Front 9

The ECM of the organic matrix of bone contains _____produced by____________

Back 9

collagen fibers produced by osteoblasts

Front 10

Describe the periosteum

Back 10

the outer covering for bone (thick)
has an outer fibrous layer made of dense CT and an inner cellular layer (composed of cells with osteogenic potential)

Front 11

_____fibers are collagen fibers which anchor the periosteum to bone

Back 11

sharpey's fibers

Front 12

desciribe the Endostem

Back 12

a single thing, inner covering layer that is loosely organized
can be divided into several regions that are continuous wiht each other

Front 13

What are the regions of the endosteum?

Back 13

diaphyseal endosteium (lining walls of marrow cavity)
Trabecular endosteum (covers trabeculae of spongy bone)
Osteonal endosteum (goes into the canals that carry blood vessels w/in bone)

Front 14

Can osteoprogenitory cells (cells that will later be osteoblasts) arrise from the endosteum

Back 14

yes, the endosteum is a potential source of osteoprogenitor cells

Front 15

The osteon is also known as

Back 15

A haversian system

Front 16

Define the osteon

Back 16

the basic unit of mature compact bone

Front 17

What are osteons composed of

Back 17

concentric lamellae or layers of mineralized bone matrix around a central canal, in which there is a blood vessel and CT

Front 18

Most osteons are oriented _____to the long axis of the bone

Back 18

parallel

Front 19

Osteocytes are found in _____that are positioned b/w the lamellae of the osteons

Back 19

osteocytes

Front 20

What are the tiny channels that connect the lacunae called

Back 20

canaliculi

Front 21

volkmann's canals

Back 21

the channels in bone that transmit blood vessles from the periosteum or endosteum into the bone, and communicate with the Haversian canals

Front 22

intramemranous ossification process:

Back 22

mesenchymal cells differentiate to osteoblasts, osteoblasts secrete osteoid, become trapped, bone spicules form and eventually fuse into solid bone. CT surrounding becomes endo and periosteum

Front 23

When bone is formed in mesenchyme w/o a cartilage model it is called

Back 23

intramembranous ossification

Front 24

What kind of bones develop via intramembranous ossification

Back 24

flat bones of the skull and other skull bones called membrane bones
and bone formation from the periosteum

Front 25

Spicule

Back 25

small needlelike structure -one of hte silicate or calcium carbonate processes supporting the soft tissue

Front 26

Trabecula

Back 26

small bar, rod, bundle of fibers
--any of the intersecting osseous bars occuring in cancellous bone

Front 27

Two ways of classifying bones grossly are

Back 27

compact and spongy bone

Front 28

where can you find compact bone

Back 28

it forms the outer shell of all bone and also the shafts in long bones

Front 29

spongy bone is found where

Back 29

at the expanded heads of long bones and fills most irregular bones

Front 30

Is trabecula a micro or macroscopic way of discribing bone

Back 30

it is a macroscopic structure (seen in the spongy part of bone)

Front 31

A spicule is a macro or micro structure

Back 31

a microscopic beam of bone

Front 32

Endochondral bone growth arrises from

Back 32

cartilage model

Front 33

endochondral ossification occurs _____

Back 33

in majority of bones in body from hyaline cartilage model

Front 34

Is there hyaline cartilage in the endochondral ossified bone?

Back 34

No, it was there as a model and was the orginal surface on which osteoid was deposited

Front 35

Chondrification

Back 35

the process of mesenchymal cells differentiated to chondroblasts

Front 36

during chondrification cartliage is growing via

Back 36

hypertrophy and then eventually will degenerate

Front 37

what causes chondrocytes to degenerate?

Back 37

a complex casscade of signals involving the periochondrium, chondrocytes, and the matrix mineralizing (becoming much more basophilic as this happens)

Front 38

The bone collar is evidence of

Back 38

bone development, one of the first signs -seen in the periostium area

Front 39

During endochondral ossification, once the cartilage becomes calcified what happens?

Back 39

blood vessels invade, bringing osteoprogenitor cells (can become osteoblasts in correct conditions). the large lacunae from the space chondrocytes were hanging out serve as the space which osteoblasts can start working- secreting osteoid on the calcified cartilage

Front 40

Where do you usually find the primary center of ossification

Back 40

the ends of the physes- interor of diaphysis (that has previously undergone endochondral ossification)

Front 41

What is the secondary center of ossification/ where is usually found

Back 41

one in each epiphysis, no bone collar

Front 42

What is the bone collar formed from

Back 42

from cells derived from the perichondrium/periosteum around the diaphysis – this is technically intramembranous ossification

Front 43

what is the role of the bone collar?

Back 43

will continue to add layers peripherally, and it will be remodeled to form the osteons of the compact bone of the diaphysis

Front 44

The physes is synonymous with

Back 44

growth or epiphyseal plate

Front 45

the physes are remanants of the ______, where the _____remain the ability to divide

Back 45

remnants of the cartilage model where chondrocytes retain ability to divide

Front 46

In the physis area the chondrocyte proliferation is _____In orientation resulting in the width/length of the bone

Back 46

linear, length

Front 47

physes can be thought of as the ends of the ___-center of ossification

Back 47

primary center, spreading toward either end of the bone and lengthening the bone

Front 48

What are the five distinct zones of the physis

Back 48

resting/ reserve
proliferation
hypertrophy
calcification
ossification

Front 49

What occurs during the zone of ossification

Back 49

capillary buds grow into tunnels previously occupied by dead chondrocytes
osteoblasts differentiate
osteoid is deposited on tunnel walls

Front 50

explain how the ossification occurs in a 3D model

Back 50

this deposition is seen as spicules with a thin core of cartilage ECM. This cartilage ECM is one key to identification of this process versus intramembranous ossification.
The spicules are later remodeled and cartilage ECM (and primary bone) is removed.

Front 51

in which zone does the cartilage matrix get mineralized

Back 51

calcification

Front 52

ossification zone is when

Back 52

osteoid is laid down

Front 53

chondrocytes in growth plate progress through a cycle of

Back 53

division, hypertrophy and death
(do not become osteoprogeniotor cells)

Front 54

how do you achieve growth in width (expansion of bone)?

Back 54

Osteoblasts in the inner layer of the periosteum deposit bone lamellae on the outer surface WHILE the osteoclasts in the diaphyseal endosteum remove bone from inner surface
NET result

Front 55

What growth process happens in the zone of proliferation

Back 55

interstitial (growth from w/in -chondrocytes

Front 56

The way that osteocytes proliferate is ___

Back 56

appositional growth- tissue added to edge

Front 57

Woven bone

Back 57

bony tissue characteristic of the embryonal skeleton, in which the collagen fibers of the matrix are arranged irregularly in the form of interlacing networks

Front 58

Through the process of remodeling woven bone is replaced by

Back 58

lamellarbone

Front 59

Lamellar or layer bone

Back 59

the normal type of adult mammalian bone, whether cancellous or compact, composed of parallel lamellae in the former and concentric lamellae in the latter; lamellar organization reflects a repeating pattern of collagen fibroarchitecture.

Front 60

Is lamellar bone ever remodeled

Back 60

continuously throught life

Front 61

how are osteons formed

Back 61

new osteons form in a tunnel behind a cutting cone of osteoclats, and a blood vessel surrounded by osteoprogenitor cells grows into the , osteoblats differentiate and line edges of tunnel.

Front 62

Spongy bone is what forms on the ____side of the growth plate and in most of the ___cavity of the epiphysis

Back 62

metaphyseal side, in most of the marrow cavity

Front 63

spongy bone remains in the form of ____even after remodeling

Back 63

form of trabeculae

Front 64

Relative to the formation of the lamellae in osteon, the reversal line is deposited

Back 64

first

Front 65

osteon/ haverian systems are evidence of

Back 65

remodeling

Front 66

reversal lines are deposited from outside in (one furthest out is the oldest)

Back 66

so think of the deposition of osteon like rust building up on a pipe, the longer the osteon has been around the smaller the central canal will be

Front 67

woven vs lamellar bone

Back 67

woven vs lamellar

Front 68

note 5 distinct zone

Back 68

note 5 zones

Front 69

note 5 distinct zone

Back 69

note 5 zones

Front 70

identify osteon being formed in vertebrae

Back 70

osteon formation in IV

Front 71

osteon (note dark lines are lacunae connected by canaliculi)

Back 71

osteon (note dark lines are lacunae connected by canaliculi)

Front 72

osteoclasts vs osteoblasts

Back 72

osteoclasts vs osteoblasts

Front 73

haverian system

Back 73

Haverian system

Front 74

endochondrial ossification

Back 74

endochondrial ossification

Front 75

Back 75

capillary growing into space chondrocyte was