TY  - CHAP
M1  - Book, Section
TI  - Cartilage
A1  - Mescher, Anthony L.
Y1  - 2021
N1  - 
T2  - Junqueira's Basic Histology Text and Atlas, 16e
AB  - Cartilage  SUMMARY  OF  KEY  POINTSCartilage  is  a  tough,  resilient  type  of  connective  tissue  that  structurally  supports  certain  soft  tissues,  notably  in  the  respiratory  tract,  and  provides  cushioned,  low-friction  surfaces  in  joints.Cells  of  cartilage,  chondrocytes,  make  up  a  small  percentage  of  the  tissue’s  mass,  which  is  mainly  a  flexible  mass  of  extracellular  matrix  (ECM).Chondrocytes  are  embedded  within  lacunae  surrounded  by  the  ECM.Cartilage  ECM  typically  includes  collagen  as  well  as  abundant  proteoglycans,  notably  aggrecan,  which  bind  a  large  amount  of  water.Cartilage  always  lacks  blood  vessels,  lymphatics,  and  nerves,  but  it  is  usually  surrounded  by  a  dense  connective  tissue  perichondrium  that  is  vascularized.There  are  three  major  forms  of  cartilage:  (1)  hyaline  cartilage,  (2)  elastic  cartilage,  and  (3)  fibrocartilage.Hyaline  CartilageThe  ECM  of  hyaline  cartilage  is  homogenous  and  glassy,  rich  in  fibrils  of  type  II  collagen  and  aggrecan  complexes  with  bound  water.The  ECM  has  less  collagen  and  more  proteoglycan  immediately  around  the  lacunae,  producing  slight  staining  differences  in  this  territorial  matrix.Chondrocytes  occur  singly  or  in  small,  mitotically  derived  isogenous  groups.Perichondrium  is  usually  present,  but  not  at  the  hyaline  cartilage  of  articular  surfaces  or  the  epiphyses  of  growing  long  bones.Elastic  CartilageElastic  cartilage  generally  resembles  hyaline  cartilage  in  its  chondrocytes  and  major  ECM  components,  but  its  matrix  includes  abundant  elastic  fibers,  visible  with  special  stains,  which  increase  the  tissue’s  flexibility.Elastic  cartilage  provides  flexible  support  for  the  external  ear  as  well  as  certain  structures  of  the  middle  ear  and  larynx;  it  is  always  surrounded  by  perichondrium.FibrocartilageFibrocartilage  contains  varying  combinations  of  hyaline  cartilage  in  small  amounts  of  dense  connective  tissue.Histologically,  it  consists  of  small  chondrocytes  in  a  hyaline  matrix,  usually  layered  with  larger  areas  of  bundled  type  I  collagen  with  scattered  fibroblasts.Fibrocartilage  provides  very  tough,  strong  support  at  tendon  insertions  and  in  intervertebral  discs  and  certain  other  joints.Cartilage  Formation,  Growth,  &  RepairAll  forms  of  cartilage  form  from  embryonic  mesenchyme.Cartilaginous  structures  grow  by  mitosis  of  existing  chondroblasts  in  lacunae  (interstitial  growth)  or  formation  of  new  chondroblasts  peripherally  from  progenitor  cells  in  the  perichondrium  (appositional  growth).Repair  or  replacement  of  injured  cartilage  is  very  slow  and  ineffective,  due  in  part  to  the  tissue’s  avascularity  and  low  metabolic  rate.  
SN  - 
PB  - McGraw Hill
CY  - New York, NY
Y2  - 2024/04/16
UR  - accessmedicine.mhmedical.com/content.aspx?aid=1184199746
ER  -