Bone and Ossifciation Flashcards

1
Q

What is the major supporting framework of the body?

A

bone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Bone is the major reservoir for___-

A

calcium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

soluable salts must be transported from blood vessels to osteocytes by…

A

canaliculi because deposits of calcium int he matrix prevent diffusion of soluble salts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what are the two forms of bone?

A

compact dense bone spongy trabecular/cancellous bone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the organic components of bone?

A

type I collagen (90%) proteoglycans and other proteins (10%)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What do the organic components of bone contribute to the structure?

A

elasticity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the inorganic components of bone?

A

calcium phosphate (hdyroxyapatite crystals)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What do the inorganic components of bone contribute to the structure?

A

Bone rigidity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What type of growth does bone illustrate?

A

appositional only (periosteum)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Periosteum surrounds

A

most bone except articular surfaces insertion of tendons insertion of ligaments

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Diaphysis

A

shaft primarily compact bone with marrow cavity at center

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Epiphysis

A

bulbous expanded ends of bone primarily spongy bone covered by thin layer of compact bone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

metaphysis

A

funnel shaped region that connects diaphysis with epiphysis SPONGY BONE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Epiphyseal plate

A

separates epiphysis from diaphysis cartiligenous connected to diaphysis by spongy bone (metaphyssis) RESPONSIBLE FOR INCREASE IN LENGTH OF GROWING BONE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

osteoclast bone reabsorbtion

A

acidic environment lose rigidity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the two types of bones?

A

Compact bones or trabecular

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Where is the outter circuferentia lamellae?

A

It is located under the periosteum, and it is the external surface of the compact bone.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What type of bone is the intersitial lamellae?

A

Compact lamellae haversian

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What type of bone is the outter circumferentia lamellae?

A

compact lamellae non haversian

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What type bone is the inner circumferentia lamellae?

A

compact lamellae non haversian

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What does non haversian mean?

A

It does not have any blood vessels in the center.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What type of bone is bone marrow?

A

Trabeclar lamellae non haverian

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

How do periosteal and endosteal communicate with the haversian canal?

A

Through the volksmanns canal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Osteonectin

A

It is made by osteoblast. It helps with the mineralization of the bone.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What type of bone is the haversian system/ osteon?

A

compact lamellar haversian bone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Where is the inner cirucmferential lamellae found

A

under the endosteum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Endosteum

A

lines marrow cavity and spaces in spongy bone

become osteoblast when repair is necessary (fractures)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Intersistial lamellae are round

A

between osteons and separated fromt hem by cement line

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Outer layer of perisoteum

A

alot of collagen and blood vessels then penetrate volksmanns canal

few fibroblast

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Inner layer of Periosteum

A

Lined with osteoproginator cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Non Callgenous Matrix Proteins of bone matrix

A

osteocalcin

osteopontin

osteonectin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Osteocalin

A

inhbiits osteoblast function/ bone mineralization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Osteonectin

A

made by osteoblast

properties in mineralization of bone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What type of growth does bone exhibit

A

appositional growht

35
Q

Where are sharpeys fibers seen?

A

outer layer of periosteum

36
Q

What do sharpays fibers do?

A

thick collagen fibers that penetrate outer layer of periosteum

37
Q

How do the cirumferential lamellae (non-haversian) get their nutrients and excrete waste?

A

the osteocytes exchange nutrients and waste products with blood vessels in the marrow cavity

38
Q

Where are osteoprogentiro cells found?

A

in inner layer of periosteum and endosteum

bone lining cells (osteocytes) but reactivate during repair of bone fractures and other injuries

39
Q

Where do osteocytes reside?

A

mature bone

lacunae of concentric lamellae

arranged between lamellae

and interconnected by canaliculi

40
Q

What does the cement line separate?

A

haversian canals from interstitial lamellae

41
Q

osteoblast are derived from

A

osteoprogenitor cells

42
Q

Osteocytes are derived from

A

monocyte-marcophage lineage in bone marrow

43
Q

osteocytes become trapped in the

A

calcified matrix of the lamellae (lacunae)

44
Q

What interconnected adjacent lacunae?

A

canniculi

45
Q

What type of junction interconnects canaliculi

A

gap junctions (ions and low molecular weight molecules)

46
Q

How do high moelcular weight molecules pass between cells

A

via diffusion through the extraceullar mediumin the canliculus surrounding the filopodia

47
Q

Filopodia

A

cytoplasmic projection

48
Q

osteopontin

A

formation of sealing zone

49
Q

Bone sialoprotein

A

mediates binding of osteoblast to ECM through integrins

50
Q

Osteoid

A

soft tissue under osteoblast

non-mineralized organic matrix

unlike bone has no calciumphosphate

51
Q

Osteocytes are

A

terminally differentiated cells in charge ofmaintaining the ECM of the bone

52
Q

osteoblast

A

synthesize osteoid

control mineralization fo the matrix

control differentiation of the osteoclast (RANKYL)

53
Q

What are hte major protein products of osteoblast

A

type 1 collagen

RANKL (osteoclast precursor cells)

osteocalcin-bone mineralization

osteopontin (formation of sealing zone)

bone sialprotein (mediate bonding of osteoblast to ECM through interins)

54
Q

The differentiation of osteoblast to osteocytes are regulated by

A
  1. Bone morphogentic protein
  2. Transforming growth factor beta
  3. cbfa1/runx2 (Transcription factors )
  4. osterix (TF)
55
Q

Alkaline Phosphatase

A

ectoenzyme (surface protein)

reacts strongly with osteoblast but disappears when osteoblast ceases protein synthesis ( becomes osteocytes)

56
Q

Vitamin D (osteoblast)

A

regulates expression of osteocalcin (mineralzation with Calcium)

57
Q

growth hormone ( osteoblast)

A

produces IGF-1/somatomedian C which stimulates growht of long bones at level of epiphyseal plate

58
Q

Parathryoid hormone

A

simtulates osteoclast of break down bone and release Calcium

59
Q

RANKYL (osteoblast)

A

receptor for activation of nuclear factor kappa B ligand (nf-kb) present in osteoclast precursor cellls

60
Q

life of bone matrix depends on

A

osteocytes

61
Q

ARe osteoclast uninuclear or multinuclear?

A

multinuclear

62
Q

Where are osteoclast found?

A

howships lacunae/substeocalstic compartment

63
Q

osteoclast create what type of environment?

A

acidic- required for bone reabsorbtion

64
Q

Osteoclast reabsorbtion

A

dissolution of inorganic parts of bone (rigidity) bone demineralization

H-ATPase

followed by enzymatic degradation of organic matrix (by protease cathepsin K)

65
Q

Osteoclast

A

Large

rich in mitocondria and acidified vesicles

ruffled border (active surface facing lacuna)

-multinucleated

66
Q

Osteoclast activity is regulated by

A

calcitonin

vitamin d3

regulatory moedlcules of osteoblast and stormal cells of bone marrow

67
Q

where is the ruffled border of the osteoclast?

A

basolateral domain

68
Q

Where is the sealing zone of the osteoclast?

A

Apical domain

69
Q

What contributes to the sealing zone of osteoclast

A

osteopontin

alpha v beta three integrin

actin

70
Q

What mechanisms do osteoclast have to maintain

the intergrit of its ph and the cytoplasm around it?

A

HC03- / CL Exchangers to pump out bicarbonate and maintain cytoplasmic electroneutrality

cloride channels to pump out cl- and maintain the acidity of the osteoclast and howships lacune

carbonic andydrase Ii (generates prtons from (co2+h20-> hc03- + h+) the h+ is relased to howships lacuna by h-atpase pump to create acididc environment )

Cathespin K released into howships lacuna to degrade epxosed organic matrix (collagen)

71
Q

What is the purpose of the sealing zone?

A

keeps the contents inside the howships lacuna

72
Q

Osteoblast are active in repsonse to calcium mobilzation in from the bone to blood

A

because it breakd down bone

73
Q

when there is less vitmain d what happens to osteoclast activity

A

it goes up

74
Q

osteoclastogenesis (osteoclast differenentiation) is triggered by 2 molecules

A

macrophage colony stimulating factor (MCSF)

nuclear fator kappa (NF-kb) ligand (RANKL)

75
Q

describe osteoclast development

A
  1. there is a monocyte with a MCSF receptor on it
  2. The osteoblast releases MSSF (macrophage colony stimulating factor ) LIgand which attaches to the receptor on the monocyte
  3. this in turn , transforms the monocyte into a macrophage
  4. this binding induces th eexpression of RANK which will will bind to RANK ligand epressed off the surfact of the osteoblast
  5. the mononucleated monocyte becuase hte mutlinucleated osteoclast precursor but still does not have the ability to absorb bone
  6. The resting (nonfunctional osteoclat uncouples fromt he osteoblast)
  7. osteoblast maturation is completed when the sealing zone of the ruffle border appears
76
Q

how is osteoclatogensis inhibited

A

by osteoprotegerin (from osteoblast) by blocking RANKL binding to receptor

77
Q

Osteopetrosis

A

bone fragility

high bone density due to absent osteoclastic activity

stone like bone

lack of MCSF

can lead to occlusion of marrow spaces and anemia

78
Q

Osteoporosis

A

fragile bone

excessive osteoclastic activity and deficient osteoblastic activity

Menopause- defc in estrogen

treatment with calcium and vitamin b

79
Q

osteomalacia

A

soft bone

defect in mineralization

vitmaind d deficiency (rickets)

chronic kidney disease

80
Q

osteosclerosis

A

increased bone mass due to increase osteoblast activitiy

81
Q

Denosumal

A

RANKl antibody

functions like osteoprotegerin

decreases osteoclastogenesis

82
Q

Intramembranous ossification

A

bones of

jaw

skull

bone is deposited directly within embroynic connective tissue

83
Q

Endochondrial Ossification

A