CARTILAGE. TENDON.
CARTILAGE.
1) CARTILAGE as an
ORGAN on the cross section is composed of 2 layers:
A) PERICHONDRIUM and B) Cartilage PROPER.
A)
Perichondrium is composed of 2 layers:1) Outer, or FIBROUS layer. Is composed of fibres and blood VESSELs. Funct.: TROPHIC
funct. for cart. proper. 2) Inner, or CELLULAR layer. Is composed of
chondrogenic cells (or PREchondroblasts). Funct. This layer and its CHONDROGENIC cs provides
APPOSITIONAL growth of cartilage.
B)
Cartilage proper is composed of usual cartilage
TISSUE, but does
NOT have blood VESSELS.
Injury of perichondrium leads to destruction and
death of cartilage proper.
(
NO perichondrium in: hyaline cart. of articular surfaces; fibrocartilage)
Cartilage TISSUE is composed of
2 components:
a) Cartilage
CELLS and b)
EXTRA
CELLULAR
MATRIX.(=ECM)
between cells.
ECM is composed of
2 components:
1)GROUND substance(glycosaminoglycans + PROTEOGLYCANs +glycoproteins) and
2) FIBRES.
If ECM contains
2 types of fibres –
collagen fibres and
ELASTIC fibres, it is
ELASTIC cartilage.
If ECM contains ONLY
collagen fibres with it
MOST amount – it is
FIBROCARTILAGE.
If ECM contains ONLY collagen fibres with it MODERATE amount- it is
HYALINE cartilage.
Differon of cartilage cells: SCLEROTOM of SOMITE - Mesenchyme - Chondrogenic cs (PREchondroblasts) - Chondro
blasts - Chondro
cytes (it are definitive).
Chondro
blasts and Chondro
cytes – are
ECM-producing cells. Funct.: secretion of : GAGs and PROTEOGLYCANs (for
ground substance); protein collagen /and elastin (for
fibres formation).
Production of ECM and mitotic division of chondrocytes provide
appositional growth of cart.
Cartilage PROPER on cross section is composed 2
zones:
-
Zone of YOUNG (or growing) cartilage. It contains single-arranged chondroBLASTS + ECM.
-
Zone of MATURE cartilage. Is composed of ISOGENOUS GROUPs of chondroCYTES+ECM.
ISOGENOUS group – is composed of
2-4 chondroCYTES, locating in common cavity, named
LACUNA. Funct.: zone of mature cartilage and its
ISOGENOUS groups – is origin of
interstitial growth of cartilage (by means of
mitotic division and
secretion of ECM).
LOCATION in organism:
ELASTIC cartilage in: a) PINNA (auricle), b) auditory tube, c) LARYNX
HYALINE cartilage in:
a) ARTICULAR SURFACES of long bones (NO perichondrium),
b)
junction between rib and sternum,
c) EPIPHYSEAL PLATE of long bone BEFORE 18-20 years. It provides
elongation of long bones. After 20 years PLATE is
CALCIFIED and body growth is
stopped,
d) early EMBRYO SKELETON is composed hyaline cart.,
e) semirings of TRACHEA and rings of main BRONCHI.
FIBROCARTILAGE (NO perichondrium) in: a) INTERVERTEBRAL DISKs, b) pubic symphysis.
Age changes: after 50 years cart. in intervetebral disks and on articular surfaces undergoes to CALCIFICATION and become pathologically FRAGILE instead usually
resilience property.
TENDON.
It is composed of: a)
DENSE REGULAR connective tiss. (mainly) and
b)
loose IRregular connective tiss (=LICT) -additionally.
a) DENSE REGULAR connective tiss. presented by: thick
BUNDLES of
collagen fibres, arranged
PARALLELLY.
b) Thin layers of
LICT between bundles, named
endotendineum and
peritendineum, carry blood vessels and fulfil TROPHIC funct. in tendon.
DENSE REGULAR connective tiss. also locates in LIGAMENTs.
DENSE
IRregular connective tiss. locates in: RETICULAR layer of skin dermis; CAPSULES, surrounding spleen, kidney. Collagen fibres in it arranged
NOT parallelly, forming meshwork.
Составитель – доцент В.В. Бондаренко.