Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Basic Tissues > Bone 2 -3 > Flashcards

Bone 2 -3 Flashcards

1
Q

Ossification

A

Bone formation; bone that first appears as woven bone, which is eventually replaced by lamellar bone

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

Primary ossification center

A

First area to start ossifying
usually during prenatal development
located in diaphysis in developing long bones

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

Secondary ossification center

A

Appears after primary
usually during postnatal development
located in epiphyses in developing long bones

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

intramembranous ossification

A

develops from mesenchyme (no cartilaginous precursor)
direct mineralization of matrix secreted by osteoblasts
Flat bones of skull (frontal, parietal, etc), lacrimal, nasal, palatine, vomer, maxilla, mandible

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

Endochondral ossification

A

Has cartilaginous precursor (template of hyaline cartilage)

  • Cartilage does not become bone! The cartilage model is replaced by bone
  • Use long bone ossification as an example
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Intramembranous ossification

A

1) Mesenchyme condenses and is highly vascularized
2) Mesenchymal cells differentiate into osteoblasts
3) osteoblasts secrete bone matrix (osteoid) to form trabecular
4) Trabeculae fuse together to form woven spongy bone
5) The periphery of the spongy bone will be remodeled into lamellar compact bone; deeper bone will be remodeled into lamellar spongy bone

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

When osteoblast gets surrounded by EC matrix it changes it’s name to

A

Osteocyte and can no longer secrete matrix bc there is no where for matrix to go

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

Endochondral Ossification Steps

A

1) Hyaline cartilage model is formed
2) Bone collar appears (around diaphysis)
Formed via intramembranous ossification within the perichondrium
Hollow cylinder of bone around the mid portion of the cartilage model
3) Chondrocyte in center hypertrophy, degernate and die. Cartilage matrix is calcified
4) Empty spaces are invaded by the the periosteal bud which is going to bring bring vasculature (vessels), mesenchymal cells, osteoprogenitor cells
5) Osteoprogenitors differentiate into osteoblasts, secrete osteoid on surface of calcified cartilage
6) Bone collar increases in thickness and length, but osteoclasts resorb the calcified cartilage and bone. Results in marrow cavity which will be populated with marrow cells
7) Secondary ossification centers form in a similar manner in the epiphyses

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

Epiphyseal plate

A

Cartilage remains at epiphyseal plate (to allow for growth in length until adulthood) and at the articular cartilage

Note: epiphyseal plates are hyaline cartilage

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

Endochondral ossification goal

A

growth in length and in width can occur. Growth in length is only possible while epiphyseal plate is present

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

Five zones of epiphyseal cartilage:

A

1) Zone of rest/reserve @ epiphysis
2) Zone of proliferation
3) Zone of maturation/hypertrophy
4) Zone of calcification
5) Zone of ossification @ diaphysis

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

Zone of Rest/reserve

A

Typical hyaline cartilage. Chondrocytes arranged randomly

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

Zone of proliferation

A

Chondrocytes undergo mitosis and are arranged in columns

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

Zone of maturation/hypertophy

A

Chondrocytes become enlarged, contain a lot of glycogen (white color) . Chondrocytes secrete alkaline phosphatase (marker of mineralization)

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

Zone of calcification

A

Cartilage matrix is calcified (purple color)

Chondrocytes are dying/dead due to calcified matrix. Leave empty lacunae

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

Zone of ossification (primary spongiosa)

A

Osteoprogenitors invade, differentiate into osteoblasts
Osteoblasts secrete matrix (osteoid) on surface of calcified cartilage
Matrix becomes calcified
Osteoclasts remove calcified cartilage and bone
Primary spongia (woven bone) is remolded into secondary spongiosa(lamellar bone)

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

Bone matrix

A

Very mineralized
Inorganic matter - 65% of dry weight. FOR HARDNESS & RESISTANCE
Consists of calcium and phosphorous (mostly ) also bicarbonate, citrate, magnesium, potassium, sodium

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

Hydroxyapatite crystals

A

Ca10(PO4)6(OH)2 calcium and phosphorous form

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

Non-crystalline in bone matrix

A

Calcium phosphate

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

Dont have a lot of calcium or phosphorous

A

bones won’t be hard

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

Hydroxyapatite crystals

A

Look like rods along collagen fibrils.

Give bones hardness and compressive strength

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

Hydratoin shell

A

Later of water around each hydroxyapatite crystal (surface ions of crystals are hydrated)
Facilitates ion exchange between the HA crystals and extracellular fluid B/w mineralized tissue and EC fluid

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

Bone matrix organic matter

A

36% of dry weight. For flexibility and strength.
Mostly type 1 collagen.
90% of organic matrix gives bone tensile strength
Triple helix, super coiled, typical 67 nm cross banding
Greater number of cross links between molecules than in non-bone tissue

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

Proteoglycans in organic matter

A

Give bone compressive strength.

Condroitin sulfate and heparin sulfate

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

Bone matrix noncollageous protein example alkaline phosphatase

A

may function in mineralization of osteoid

Blood serum levels increase during active bone formation which is used as a marker for bone formation

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

Other noncollageous proteins:

A 
Cell attachment molecules: 
-fibronectin
-Thrombospondin
-Bone sialoprotein
-Osteopontin
Growth factors:
-Fibroblast growth factors (FGFs)
-Insulin-like growth facts (IGFs)
-Transforming growth factors )Beta TGF-Beta
-Bone morphogenic proteins (BMPs)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Bone cells which originate from mesenchymal

A

Osteocyte, osteoblasts, osteogenic cell (osteoprogenitor)

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

Bone cells which originate from meatopoietic (bone marrow, specialized macrophages)

A

Osteoclast

29
Q

Osteoprogenitor cells

A

Mesenchymal stem cells
on bone surface (inner osteogenic layer of periosteum)
active during bone growth, factor repair, bone remodeling
Differentiate into osteoblasts (under the influence of TGF beta and BMP)

30
Q

When you need osteoblasts what do you have?

A

TGF beta and BMP

31
Q

Osteoblasts come from

A

Osteoprogenitor -> Preosteoblast -> osteoblast
Lines surfaces of bone tissue
Cannot be surrounded by bone matrix
Cuboidal to columnar shape when active in matrix synthesis; more squamous when less active

32
Q

Functions of osteoblasts

A

Synthesis of unmineralized bone matrix (osteoid)
Osteoclas stimulating factos
Involved in matrix mineralization

33
Q

If osteoblast is surrounded by bone matrix it becomes

A

osteocyte

34
Q

if osteoblast is not surrounded by bone matrix it becomes

A

bone lining cells

35
Q

Osteoblasts can become

A

osteocytes or bone lining cells

36
Q

Osteoblasts secrete

A

osteocalcin and alkaline phosphatase

37
Q

Matrix mineralization Steps

A

1) Osteocalcin and various glycoproteins bind Ca2+
2) Alkaline phosphatase and other enzymes in the matrix vesicles raise local concentration of PO4 -
3) Calcium phosphate and HA crystals form on matrix vesicles
4) Solid bony matrix is formed

38
Q

In presence of PTH (parathyroid hormone), osteoblasts release..

A

macrophage colony-stimulating factor (M-CSF) that induces formation of osteoclast precursors

39
Q

What differentiates into osteoclasts

A

Preosteoclasts differentiate into osteoclasts

40
Q

Preosteoclasts have what on the cell surface?

A

Have RANK

41
Q

Osteoblasts have what on surface?

A

RANKL

42
Q

What happens when RANK binds to RANKL on osteoblast?

A

preosteoclast will mature into osteoclast

43
Q

Release osteoclast-stimulating factor (OSF) does what?

A

activated osteoclasts to reabsorb bone

44
Q

Osteopontin (OPN)

A

steals osteoclasts to bone so they can absorb bone

45
Q

Steps to osteoblasts recruiting osteoclasts

A

1) Osteoblast secrete mCSF to induce the division of osteoclast presursors
2) Has rank ligand which binds to ligand on osteoclast precursor to tell it to differentiate to osteoclast
3) Activates the osteoclast
4) RANKL binds to RANK
5) Secretes OSF and OPN to activate osteoclasts
6) Inhibit osteoclast activity by producing OPG

46
Q

Osteoprotogerin (OPG)

A

Produced by osteoblasts. Binds to RANKL and blocks RANK b/c when RANK binds to RANKL it will increase osteoclast activity
Inhibits differentiation of osteoclast precursors into mature osteoclasts
Regulates osteoclast activity

47
Q

What increases rate of absorption aka osteoclasts

A

M-CSF, RANKL, OSF, OPN

48
Q

What decreases rate of bone resorption

A

OPG

49
Q

Osteocytes

A

When osteoblasts surround themselves with matrix, they become osteocytes

50
Q

The space in the matrix for each osteocyte

A

Called lacuna

51
Q

Tunnels for osteocytes

A

Osteocytes have long cytoplasmic processes, these are in tunnels called canaliculi (in order to get oxygen and nutrients)

52
Q

Osteocytes nutrients, gas, waste exchange

A

Can’t occur through mineralized matrix.
Because osteocyte processes contact each other via gap junctions
Exchange using the gap junctions can provide nourishment for a chain of about 10 cells

53
Q

Function of osteocyte:

A
  • Maintain matrix

- Mechanosensory: detect mechanical loading and therefore need for bone increase or decrease

54
Q

Osteoblast is

A

alkaline phosphatase positive

55
Q

Lining cell

A

Alkaline phosphatase negative

56
Q

Osteocyte

A

Alkaline phosphatase negative

57
Q

Osteoblasts become osteocytes. 2 kinds:

A

1) Surronds itself with bone matrix = osteocyte

2) Doesn’t surround itself with bone matrix

58
Q

Osteoclasts

A

Derived from bone marrow cells
Large, multi-nucleated, mobile
Have microvili
Sits on Howship’s lacuna when bone is removed

59
Q

Howship’s lacuna

A

What osteoclast sits on

60
Q

Bone remodeling (bone will be resorbed)

A

Done by basic multicellular unit (BMU), a wandering team of cells that dissolves an area of the bone surface that fills it with new bone

61
Q

Remodeling follows which sequence

A

ART
Activation
Resporption and reversal
Formation and mineralizaition

62
Q

How bone remodeling happens:

A

1) Activation of BMU
2) Resorption of bone by osteoclasts
3) F Formation of new bone by osteoblasts (process is reversed here and more bone is being added)

63
Q

How does cortical bone remodel?

A

outside part :note
Remodels by osteoclastic tunneling
Osteoclastic resorption -> layering of osteoblasts -> formation of lamellae
Osteoclasts make up head of cutting cone, following by capillaries then osteoblasts which lay down osteoid will fill the cutting bone
Has blood vessel

64
Q

How does spongy bone remodel?

A

Osteoclastic respiration and osteoblastic deposition of layers of lamellae
No osteons are formed (no concentric circles of lamellae around a vessel)
No blood vessels

65
Q

Bone remodeling absorption and deposition..

A

an equal amount of bone respiration and deposition
No change in overall bone mass
Replace old bone with new bone

66
Q

Bone modeling bone mass

A

changes in bone mass and changes in bone form
changes in size and shape due to resorption and deposition in unequal amounts and on different surfaces
Due to development and changes in loading patters

67
Q

Bone growth causes length change because..

A

cartilage grows here
cartilage added by bone here
cartilage grows here
cartilage replaced by bone here

68
Q

Remodeling growing shaft is remodeled by:

A

bone being resorbed at epiphyseal plate
bone added by appositional growth
Bone resorted

Basic Tissues (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions