1. Cartilage
Bone

2. PRINCIPAL FUNCTIONS OF
CARTILAGE
supporting soft tissues
covering the surfaces of bones
forming the bone joints
(shock absorber and sliding area)
development and growth of long
bones

3. Chondrocytes
Extracellular matrix
GROUND SUBSTANCE
FIBERS
Glicosaminoglicans
(GAG)
collagen
fibers
Proteoglicans
elastic fibers
hyaluronic acid

4. PERICHONDRIUM
The capsule of connective tissue covering
the cartilage
outer layer - dense connective tissue
collagen type I
fibroblasts
the source of nutrients for avascular
cartilage
inner layer
chondroblasts - precursors of chondrocytes

6. TYPES OF CARTILAGE
Hyaline cartilage
the most common form
contains mainly collagen type II fibers
Elastic cartilage
many elastic fibers near the collagen type II
more pliable than hyaline cartilage
Fibrocartilage
dense network type I collagen fibers
present in regions subject to great mechanical
stress

7. HYALINE CARTILAGE
articular surfaces of bones forming
movable joints
the walls of big respiratory passages
larynx, trachea, bigger bronchi
epiphyseal plates of long bones
the cartilaginous parts of ribs
covered by perichondrium
(except articular cartilage)

9. HYALINE CARTILAGE
CHONDROCYTES
develop from chondroblasts - cells present in
the inner layer of the perichondrium
at the periphery - elliptic shape
farther in - become round , form isogenous
groups
isogenous group - develops by mitosis of
single chondrocyte (5-8 cells in group)
produce all components of extracellular matrix
well developed RER, Golgi complex

11. HYALINE CARTILAGE
EXTRACELLULAR MATRIX
collagen type II fibrils embedded in ground
substance
ground substance :
proteoglicans
chondroitin sulfate, keratan sulfate
long chains of hyaluronic acid
chondronectin - glycoprotein providing
adherence of collagen and chondrocytes
water bound to the negative charges of
glicosaminoglicans

12. Territorial matrix
surrounds each chondrocyte of isogenous
group
rich in proteoglicans poor in collagen fibrils
Interterritorial matrix
occurs between isogenous groups
numerous collagen type II fibrils
Characteristics
firm, resistant to compression

15. ELASTIC CARTILAGE
auricle of the ear
the wall of external auditory canals
auditory tubes (Eustachian tubes )
epiglottis
Presence of perichondrium

16. ELASTIC CARTILAGE
Chondrocytes
similar to cells of hyaline cartilage
smaller isogenous groups ( 2- 3 cells)
Extracellular matrix
abundant network of elastic fibers
collagen type II fibrils
ground substance : the same components
like in hyaline cartilage

19. FIBROCARTILAGE
annulus fibrosus of intervertebral disc
symphysis pubis
attachments of ligaments
Great resistance to extention

20. FIBROCARTILAGE
Chondrocytes
identical to cells of hyaline cartilage
single or in groups
groups - long raws of chondrocytes
Extracellular matrix
ground substance - less abundant
numerous collagen type I fibers - bundles
collagen bundles:
parallel to raws of cells
visible in light microscope

21. BONE
Specific type of connective tissue with
calcified extracellular substance
Functions
supporting soft tissues
protection of important organs
CNS in skull
thoracic contents in chest
reservoir of calcium

23. OSTEOBLASTS
form a layer which resembles the simple
epithelium on the surface of bone
surround themselves with matrix and become
ostecytes
basophilic cytoplasm
abundant RER, well developed Golgi complex
Functions:
synthesize the organic components of matrix
responsible for calcification of bone matrix
play certain role in bone resorption

25. OSTEOCYTES
develop from osteoblasts which surrounded
themselves with matrix
are located in matrix lacunae
(one cell per lacuna)
contact to each other by mean of cytoplasmic
processes existing in canaliculi of matrix
surrounded by thin layer of noncalcified matrix
less RER, smaller Golgi complex condensed
nuclear chromatin
Function: maintenance of the matrix

26. OSTEOBLASTS
OSTEOCYTES

28. OSTEOCLASTS
large, multinuclear cells
derive from monocytes
(belong to phagocyte
system)
ruffled border - surface facing
bone ruffled
clear zone - adhesion the cell to
the matrix
acidophilc cytoplasm
abundant RER and Golgi
complex numerous
mitochondria and lisosomes
Functions: bone resorption
bone growth and bone
remodeling

29. OSTEOCLASTS

32. BONE
EXTRACELLULAR MATRIX
Organic components ( 30-35% of bone weight)
collagen type I fibers ( 90%)
noncollagenous proteins :
osteonectin, osteocalcin, sialoproteins,
phosphoproteins, proteolipids
proteoglicans
Inorganic components ( 70% of bone weight)
calcium phosphate - hydroxyapatyte crystals

33. Periosteum
Layer of connective tissue covering the bone
Outer layer - dense connective tissue
fibroblasts
numerous collagen fibers
rich in blood vessels
(source of vessels for bone)
Inner layer
osteoprogenitor cells
(reservoir of osteoblasts)

34. Endosteum
Thin layer of connective tissue with
osteoprogenitor cells
Lines internal surfaces of the bone

35. Types of bone
IMMATURE BONE = PRIMARY BONE =
= woven bone
MATURE BONE = SECUNDARY BONE =
= lamellar bone


Compact bone
Cancellous bone = spongy bone

36. SECUNDARY BONE
MATURE BONE
Present in adults
Characteristics
smaller number of osteocytes
bone matrix
abundant, well calcified
arranged in lamellae
regular arrangement of collagen fibers
lamellae form osteons (Haversian systems)
great resistance to mechanical forces

37. SECUNDARY BONE
MATURE BONE

38. Endosteum
Thin layer of connective tissue with
osteoprogenitor cells
Lines internal surfaces of the bone

42. PRIMARY BONE
IMMATURE BONE
formed in embryo during bone formation
develops in repair process after fracture
replaced by mature bone
irregular array of collagen fibrils in the organic
part of matrix
smaller calcification
many osteocytes, little of bone matrix
smaller mechanical resistance

43. HISTOGENESIS
Intramembranous ossification
on the ground of mesenchymal tissue
formation of flat bones
e.g. bones of the skull
Endochondral ossification
on the ground of cartilaginous model
of the bone
formation of long bones

44. INTRAMEMBRANOUS
OSSIFICATION
1. penetration of blood vessels into
mesenchymal tissue
2. mesenchymal cells differentiate into
osteoblasts
3. formation of bone spicules

45. ENDOCHONDRAL
OSSIFICATION
1.
formation of bone collar within an
inner layer of perichondrium of the
diaphysis
(intramembranous ossification)

46. ENDOCHONDRAL
OSSIFICATION
2.
hypertrophy of chondrocytes
deposition of calcium salts in the
cartilage matrix
degeneration of chondrocytes

47. ENDOCHONDRAL
OSSIFICATION
3.
penetration of osteogenic bud across
bone collar into degenerated cartilage

48. ENDOCHONDRAL
OSSIFICATION
4.
phagocytes resorb the cartilage
osteoblasts start the production of
bone matrix on the remnants of
cartilage
PRIMARY OSSIFICATION CENTER

49. BONE GROWTH
FLAT BONES
1. Formation of bone on the external surface
osteoprogenitor cells of periosteum
(intramembranous ossification)
2. Resorption of bone on the internal surface
osteoclasts

50. BONE GROWTH
LONG BONES
epiphyses - radial growth of cartilage
cartilage is gradually replaced by bone
the diaphysis increases in width by
formation of bone by periosteum on the
external surface
diphyseal shaft grows in length as a result
of the osteogenic activity of epiphyseal
plate.

51. BONE AND CALCIUM REGULATORY FACTORS
Parathormone
(parathyroid)
Bone Resorption
Osteoclasts
Osteocytes
“osteocytic osteolysis”
Bone Growth
Somatotrophin
(pituitary)
Calcium
Flux
Calcitonin
(parafollicular cells
of thyroid)
Nutritional Factors:
Calcium & Vitamin D Deficiency
Child- Ricketts
Adult- osteomalacia
Vitamin C Deficiency
Scurvy- matrix not calicifiable