S03: Cartilage, Bone and Ossification Flashcards
Cartilage is highly hydrated. What 2 benefits does this provide?
it can withstand significant compressive forces
provides an almost frictionless surface for other cartilages to move across
Can cartilage repair? Why?
No because it is avascular
What are three types of cartilage?
Describe their structure and function
Where are they found?
hyaline/articular - articulating surfaces, highly hydrated, GSG’s, parallel collagen fibres,
fibrous - pubic symphysis, IVD’s, joint capsules, ligaments
elastic - external ear, epiglottis, larynx
All synovial joints in the body are lined with hyaline cartilage. True or False.
False, all expect the temperomandibular joint with is fibrocartilage
What compounds are found within the ground substance of hyaline cartilage that trap water and keep the cartilage hydrated?
glycosaminoglycans x3:
hyalouronic acid
chondrotin sulphate
keratin sulphate
Name the layers of cartilage and describe the processes going on in each layer.
Tangential layer - articulating surface, parallel arrangement of collagen fibres
Intermediate layer - chondrocytes are large and collagen fibres are arranged obliquely
Radial layer - collagen fibres and groups of chondrocytes are oriented perpendicular to bone
Calcified layer - merges with underlying bone and is partly calcified
What is the main source of nutrients for cartilage? Where else can it receive nutrients from?
synovial fluid
diffusion from blood vessels in underlying bone
Like other tissues, cartilage constantly undergoes tissue turnover. When is cartilage degeneration seen/
During prolonged bed rest when anabolism is slowed
Excessive loaded where anabolic activity is unable to respond sufficiently
Describe the degenerative process in osteoarthrtitis
Changes in articular cartilage, stress chondrocytes, release tissue breakdown products which exacerbate the situation, cartilage softens, surface layers become uneven and cause friction on movement. Necrosed tissue surrounded by clumps of proliferating chondrocytes. Underlying bone is exposed, micro fractures in trabeculae, osteoblasts respond by forming new bone, cycle of regeneration and degeneration
Whatever their shape, bones are covered in ……….., except at their ………. …….. where there is ………. .
periosteum
articulating surfaces
cartilage
Periosteum, formed by two ……… …….., contains ……. which are capable of proliferation, and are especially important in ……… ………
cartilagenous layers
osteoblasts
healing fractures
In developing bone, or in bone formed immediately after ……., the collagen fibres are arranged ………… . This bone is termed ……….. and this broken down by ……… and remodelled to form the two types of adult bone: ……… and …….., both of which are slowly remodelled throughout life. The …….. nature of bone means that it can adapt to different ………….. ………..
fractures randomly woven bone osteocalasts cortical cancellous dynamic environmental stresses
Describe the structure of cortical bone.
Osteoblasts have laid down matrix in concentric rings known as osteons surrounding a central canal containing blood vessels, nerves and a lining of osteoblasts
Where do larger blood vessels enter bone?
nutrient foramina which are easily seen on bony specimins
The hollow interior of most bones is supported by ……… - bony struts which are arranged along …….. ……… - forming the more open ……………. bone. This marrow bone, has spaces containing ……… ….. (red marrow) or ….. (yellow marrow).
trabeculae stress lines cancellous haemopoetic cells fat
