Bone Flashcards
What is cartilage and where is it found?
Connective tissue
Where flexibility is required
Give an advantage and disadvantage of cartilage being avascular
ADV: no blood loss in surgery
D.ADV: takes longer to heal as supplies enter via diffusion only
Name the three types of cartilage
Hyaline cartilage
Elastin cartilage
Fibro cartilage
Name the connective tissue that surrounds a) cartilage and b) bone (not at articulation sites)
a) perichondrium
b) periosteum
What is bone and whats is primary function?
Hard connective tissue
Provide a ridged framework
Name and describe the 4 types of bone cells.
Osteoprogenior cells -stem cells
Osteoblasts- make bone, arranged in lines similar looking to squamous epithelial cells. Influenced by HGH.
Osteocytes- fixed osteoblasts within bone that maintain it
Osteoclasts- destroy bone, found at sites where bone is being remodelled. They have a ruffled border that secrete destructive enzymes.
Describe the roles of a) Haversian canal b) Lacunae and c) Lamallae in compact bone
a) contain neuromuscular supply
b) each osteocyte occupies its own. Radiating from each are canaliculi which provide the osteocytes with nutrients
c) concentric layers laid down by osteoblasts that form the Haversian canal
Describe two features of spongy bone which make them different to compact bone
They have irregular lamallae
They are very vascular as they are surrounded by red bone marrow
For each class of bone give an example and a description where applicable
Long bones (tubular)- humerus Short bones (cuboidal)- wrist and ankle bones Irregular bones- face Sesamoid bones (round or oval bones completely covered in tendon)- knee cap, them and big toe Flat bones (two compact bones separated by spongy bone)- skull
What part of the mesoderm is bone specifically derived from?
Paraxial and lateral
Describe the processes involved in intramembranous ossification
- Mesenchymal stem cells form primary ossification centre
- They aggregate and differentiate into osteoblasts
- Osteoblasts produce asteroids
- Some osteoblasts become trapped within centre of
- newly forming osteoblasts thus forming osteocytes
- Osteoids calcify forming hardened bone matric
- Cells continue to divide and condense around the capillary network
- Mesenchymal cells and collagen differentiate to form periosteum
Which types of bones are mainly made from intramembraneous ossification?
When does it typically take place and what type of tissues are mineralised.
Flat bones such as manible, skull and clavicle
Within first 2 years
Hyaline cartilage and fibrous tissue
Describe the processes involved in endochondral ossification
- Perichondrium becomes vascularised which stimulates mesenchymal stem cells at primary ossification site to differentiate into osteoblasts
- Newly formed osteoblasts gather at diaphysis wall forming bone collar
Epiphyseal plate exists between diaphysis and epiphysis (primary and secondary ossification centres)
Epiphyseal plate abolished with maturity.
What does bone growth involve?
partial reabsorption of previously laid down bone and laying down of new bone
State the 5 vitamins involved in bone development
Vitamin A- bone remodelling Vitamin C- connective tissue Vitamin D- calcium absorption Calcium Phosphorus
