Bone and Cartilage Flashcards
(24 cards)
give components of cartilage
chondrocytes that produce extracellular matrix
large ratio of glycosaminoglycans to type 2 collagen in matrix allows for diffusion of nutrients between chondrocytes and blood vessels
the extracellular fluid has hyaluronic acid that makes it strong and pliable.
hyaluronate proteoglycan aggregates are interwoven with network of collagen fibres
Hyaluronate proteoglycan aggregates = proteoglycan monomers (protein + glycosaminoglycans) + hyaluronic acid
what are the components of hyalin cartilage matrix? and what produced the matrix
chondrocytes secrete the matrix
proteoglycans
hyaluronic acid
type 2 collagen
what are the two layers in hyaline cartilage and what types of growth occur at both?
perichondrium - appositional growth from developing chondrocytes
extracellular matrix - chondrocytes = interstitial growth
where can hyaline cartilage be found?
precursor model for bones in the fetal skeleton
at articulating surfaces of bones such as the ribcage, larynx, nose, trachea, and bronchi
and at the epiphyseal growth plates
what are the components fo elastic cartilage and what properties does it have?
proteoglycans
hyaluronic acid
type2 collagen
+ elastic fibres
give elasticity to cartilage in addition to the resilience characteristic of hyalin cartilage
what can hyalin cartilage do which elastic cartilage cannot?
calcify with age
where can elastic cartilage be found?
external ear (pinna)
Eustachian canal
epiglottis
describe fibrocartilage
combination fo dense regular connective tissue and hyalin cartilage
cells are distributed in rows and there is no surrounding perichondrium
components of extracellular matrix of fibrocartilage
proteoglycans
hyaluronic acid
type 2 collagen
and lots of type 1 collagne - thick between rows of chondrocytes
where can fibrocartilage be found and what is its role?
intervertebral discs
menisci of joints
pubic symphysis
shock absorber and resists shearing forces
give four functions of bone
mineral storage (e.g. calcium hydroxylapatite crystals)
support
protection
Haemopoiesis
define bone
a vascular connective tissue consisting of cells and calcified extracellular matrix.
there are two types spongy and compact.
describe the extracellular composition of bone
extracelluar matrix is caclified to act as a store of minerals e.g. calcium hydroxyapatite crystals. and consists of organic matter e.g. T1collagen, sulphated glycoproteins, proteoglycans and bound water.
describe the composition of bone in terms of cells
osteoblasts - synthesise and calcify bone matrix, control formation, recruitment and maintenance of osteoclasts, initiation fo bone reabsorption
osteocytes - responsible for short term calcium and phosphate homeostasis of body
osteoclasts - bone resorption
define cartilage
an avasular tissue consisting of extensive extracellular matrix in which lie chondrocytes
it is a supporting framework for organs, articulating surfaces of bone and fetal skeleton
describe the microstructure of compact bone
denser than cancellous lamellar organisation is more precise and thicker covered by connective tissue marrow lined endosteum periostium
describe the microstructure of cancellous
surrounded by compact bond
large open spaces for marrow
a network of fine bony columns and plates = trabeculae with several layers of lamellae.
what is the cause of achondroplasia and give the morphological features?
point mutation in fibroblast growth factor receptor 3 gene.
autosomal dominant.
narrow epiphyseal growth plate - limbs v short
vault of skull enlarged but face is small. bridge of nose flattened
normal intelligence
what are the common risk factors for osteoporosis?
use of steriods genetic predisposition age white or asian descent women diet - insufficient absorption and vit D smoking, alcohol and sedentary lifestyle
what are the gain in function results of the point mutation of achondroplasia?
poitn mutation in the fibroblast growth factor receptor gene =
decreased endochondral ossification
inhibited growth of chondrocytes in growth plates
decreased cellular hypertrophy
decreased cartilage matrix production
define osteoporosis
a metabolic bone disease in which mineralized bone is decreased in mass to the point that it no longer provideds adequate support
there is enhanced bone resorption relative to bone formation
loss of mass in trabecular bone is particularly relevent to increase risk of fracture.
describe the affect of 1,25 dihydroxylvitamin D3
increases calcium absorption in the small bowl
promotes mineralisation of bone
describe the symptoms of Rickets
insufficient calcium deposition for adequate bone rigidity
long bonds become soft and malformed
distortion fo skull bone
enlargement of costochondral junctions of the ribs
describe the symptoms of osteomalacia
bone pain
back ache
muscle weakness
