BONE DEV 1

dr. Indriati Dwi Rahayu

Dept. Of Anatomy-Histology

University of Brawijaya Malang

BONE BONE DEVELOMENTDEVELOMENT

FUNCTION & COMPOSITION

BONE CLASSIFICATION

OSTEOGENESIS

REGULATION

FUNCTION5 MAIN FUNCTIONS:

1. Support (give body shape and structure)

2. Protection (protect internal organs)

3. Movement (joints allow for motion)

4. Mineral storage (calcium, phosphorus)

5. Blood cell production (marrow)


COMPOSITION

• water (25%)

• organic constituents (25%): incl.

osteoid (the carbon containing part of the matrix)

bone cells

• inorganic constituents, mainly calcium phosphate

(~ 50%).

A Chemical Analysis of Bone

COMPONENT Matrix Intercellular : acidophilic

* Fibers : type I collagen; in overlapping pattern

* Ground substance

ORGANIC : proteoglycan, glycoprotein, keratan sulfates

ANORGANIC : * Calcium * Phosphate

Ca-phosphate amorph (hydroxyapatite)

- bicarbonate, sitrat, Mg, K, Na

CELLS


BONE CLASSIFICATION

OSTEOGENESIS

REGULATION

Based on textures:• Spongious bone (trabecular bone, cancellous bone, spongy)• Compact bone (dense bone, cortical bone)

Based on matrix arrangement :• Woven bone (primary bone tissue): • Lamellar bone (secondary bone tissue):

Based on maturities :• Immature bone (primary bone tissue): Immature bone is woven

bone. • Mature bone (secondary bone tissue). Mature bone

characteristically is lamellar bone.

Based on histogenesis • Intramembranous bone (mesenchymal bone)• Intracartilaginous bone (cartilage bone, endochondral bone)

Based on textures:Sponge bone (trabecular bone,

cancellous bone)

Can be primary on secondary

Compact bone (dense bone, cortical bone)

Must be secondary

Trabecular ; lamellar

COMPACT bone

• always as secondary bone

• Trabecula <<

DISTRIBUTION :

• Long Bones :

[epiphysis] spongious, covered by a

thin layer of compact bone

[diaphysis] almost totally composed

of compact bone, with a small

component of spongy bone on its

inner surface around the bone

marrow cavity.

• Flat bone :

two layers of compact bone

called plates (tables),

separated by a layer of spongy

bone called the diploe.

• irregular bone:

a core of spongy bone

completely surrounded by

compact bone


BONE CLASSIFICATION

OSTEOGENESIS

REGULATION

HISTOGENESISHISTOGENESISHISTOGENESISHISTOGENESIS

Tulang PRIMER(Wovenbone)

Tulang PRIMER(Wovenbone)

Tulang SEKUNDER(Lamellar bone)

Tulang SEKUNDER(Lamellar bone)

PenulanganEndochondralPenulangan

EndochondralPenulangan

IntramembranousPenulangan

Intramembranous

INTRAMEMBRANOUS

Ossification

ENDOCHONDRAL

Ossification

INTRAMEMBRANOUS OSSIFICATION

They formed directly into bone ( de novo)

the Skull bones ( flat bones) were NEVER cartilage!

the source of most of the flat bones

also contributes to the growth of short bones and the

thickening of long bones.

The ossification centers of a bone grow radially and

finally fuse together, replacing the original connective tissue

Primary ossification center (starting point for ossification)

1. condensation of mesenchymal cells differentiate

osteoblast

2. osteoblast produce bone matrix and calcification

follows (Osteoid) encapsulation of some osteoblasts

osteocytes

3. islands of developing bone = TRABECULAE

4. Walls delineate elongated cavities containing capillaries,

bone marrow cells, and undifferentiated cells

5. Several such groups arise almost simultaneously at the

ossification center, so that the fusion of the walls gives the

bone a spongy structure.

Blue arrow - mesenchymal cells

Green arrow - osteocytes

Red arrow - Bone from Intramembraneous Oss. = trabeculae

ENDOCHONDRAL OSSIFICATION

takes place within a piece of hyaline cartilage whose shape resembles a model of the bone to be formed

Bone matrix deposition in the cartilage matrix

• Epiphysis remains cartilaginous and continues to grow Secondary ossification center (Forms spongy bone)

• Compact bone deposited in diaphysis by primary ossification center

• Spongy bone deposited in epiphysis by secondary ossification center

• responsible for the formation of short and long bones

1. Hyalin Cartilage Model

2. Periostal bone collar

- capillary invasion to the

perichondrium

- mesenchyme

osteoprogenitor

osteoblast secrete

matrix spiculae fusi

periostal bone collar

(Mx : intramembranous)

3. Chondrocyte near the collar PROLIFERATE isogenous groups parallel to the bone’s long axis.

Chondrocyte HIPERTROPHY (large, rounded) not separated by matrix superlacuna

CALCIFICATION of cartilage matrix between the superlacuna difusion failed hypertropic chondrocytes die

Formation of the primary marrow cavity (by chondroclast)

4. Periostal Bud penetrate the

primary marrow cavity, bring

the cells on the cartilage

matrix surface

5. OSSIFICATION : osteoid

deposition mineralization.

primary bone.

44

55

the calcified cartilage appears basophilic,

and the primary bone is eosinophilic

6. Secondary ossification center in epiphyses

Zona2 pd Epiphyseal cartilage + METAPHYSIS Epiphyseal plate

66

OSSIFICATION CENTERS

- In long bones :

* primer : mid

* sekunder : epi

enlarge seperated by epiphyseal plate

* tertiary ossification center : form the bony tubercles,

ridges for attachment of muscles, ligament

• SECONDARY BONE TISSUE (Mature = lamellar)

* by REMODELLING

* Feat : - collagen fibers positioned parallel

eachother

Osteon/Sistem Havers

REMODELLING• osteoclast erode the primary bone matrix cavities• Invasion the cavities by blood vessel, nerve, & lymphvessel• Deposit osteogenic cells (from perivascular) on the cavity wall• Differentiated to osteoblast + osteocyte• deposit secondary bone in concentric layers lamellae oldest: farthes from the vessels

Pertumbuhan Tulang

- till early adulthood, continously

with remodelling

- DIRECTION :

# growth in LENGTH:

By chondrocyte division in

epiphyseal zone

# Growth in girth

• by proliferation &

differentiation of

osteoprogenitor cells in the

inner layer of periosteum

• Bone deposition on the

outer surface of bone

BONE REPAIR

- Fractures tear vessel hemorrhage clot formation.

- macrophage remove the clot, fibroblast fill the space with fibrous connective tissue

- certain cells differentiate into chondrocyte

CALLUS (soft)

(islands of fibro cartilage & hyaline cartilage as model of ossification)

callus replaced by primar bone(bony callus) remodelled secondary bone


BONE CLASSIFICATION

OSTEOGENESIS

REGULATION & Clinical Correlation

Hormonal Control involves the interplay among the actions of : PTH, increases blood calcium levels calcitonin, decreases blood calcium levels vitamin D, helps Calcium absorbtion in intestine &

decreases renal Calcium excretion Other hormones (ex: cortisol, growth hormone,

thyroid hormone, and the sex hormones. Growth hormone and thyroxine increase bone mass)

Osteoporosis

Cx : bone formation <<, bone resorbtion >>

decrease bone mass (ratio mineral : matrix normal)

Calcium Deficiency poor calcification of bone matrix

# chronic in children: Rickets (bone deformity)

# chronic in adult : Osteomalacia (decrease bone mass ,

ratio mineral : matrix : sub normal)

CLINICAL CORRELATION

Dwarfism

• Achondroplastic– long bones stop growing in

childhood• normal torso, short limbs

– spontaneous mutation during DNA replication

– failure of cartilage growth

• Pituitary – lack of growth hormone– normal proportions with

short stature

ENJOY YOUR TIME TO LEARN….

EXAM IS JUST ANOTHER DAY IN THE FUTURE…

DON’T WORRY…..BE HAPPY…

BONE DEV 1

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