Bones Flashcards
Highlight the functions of bone.
Support
Protection
Mineral storage
Blood formation
What part of the bone structure is responsible for blood formation?
Red bone marrow
Which bone type is referred to as ‘spongy’?
Trabecular bone
What are the two types of membrane associated with bone anatomy?
Periosteum
Endosteum
What is an Osteocyte?
A bone cell, formed when an osteoblast becomes embedded in the matrix it has secreted
Where is the Periosteum found?
Covering the bone
Where is the Endosteum found?
Covering internal surfaces
Describe the structure of Osteons.
Circular structures made of concentric rings of bone matrix
Central Haversian canal contains blood vessel
Osteocytes connected by web of Canaliculi
True or False, both Trabecular and compact bone contain osteons.
False
Only compact bone contains Haversian systems
Describe the basic structure of trabecular bone.
Network of lamellated trabeculae
Gaps in-between trabeculae filled with bone marrow
What are the two types of bone formation?
Endochondral
Intramembranous
Which bone development type is used for growth of long bones?
Endochondral
Ossification = bone growth
Yay or nay?
Yay
The cartilage model refers to which type of bone growth?
Endochondral
True/False, in Endochondral ossification, the growing bone begins as cartilage.
True
Cartilage is replaced with bone in ossification centres
Describe the function of the Epiphyseal growth plate.
Allows more bone growth when needed
Aka growth plate
What are the main stages of Intramembranous ossification?
Mesenchymal stem cells develop into osteoprogenitor cells
Osteoprogenitor cells mature to osteoblasts
Residual Mesenchymal cells develop into blood vessels + bone marrow
True/false,
Only intramembranous ossification takes place in adult cortical bone.
False
Endochondral + intramembranous ossification can both take place in adult cortical bone
What is the pure fancy name for new bone matrix?
Osteoid
unmineralised matrix
What (main) 3 cells are in bone?
Osteoblasts
Osteocytes
Osteoclasts
What do Osteoclasts do?
Resorption - removal of bone tissue
What makes up the ECM of bones?
Hydroxyapatite crystals
Collagen (1)
Water
Why are minerals important for bones?
Stiffness
Compressional strength
Why is collagen needed in bones?
Tensile strength
Flexibility
Where are osteoblasts made?
Membranes
Periosteum + endosteum
What are osteoblasts?
Immature bone cells
Mesenchymal stem cells ==> Osteopregenitor ==> Osteoblasts
How are osteocytes made?
Osteoblasts bury themselves in secreted bone matrix
What are osteocytes?
Mature bone cells found inside lacunae
What is the purpose of Canaliculi?
Connect lacunae to each other
Communication network for osteocytes
What are osteoclasts derived from?
Monocytes / Macrophages
Where are osteoclasts found?
On the bone surface
What is the ‘ruffled border’ of an osteoclast?
The area in contact with the bone surface
Site of resorption
What is a Howship’s lacunae?
The resorption pit under an osteoclast
True/False,
in the context of bones, lacunae generally refers to pits?
True
Osteocytes live in lacunae
Osteoclasts create Howship’s Lacunae
Where are collagen fibres found in the bone?
ECM
Describe the arrangement of the ECM.
Collagen fibres cross linked with large gaps
Gaps provide space for water and hydroxyapatite crystals
Osteoporosis arrises due to…
Resorption > Formation
Yay or Nay
Paget’s disorder arrises due to an imbalance in resorption/formation
Nay
Both happen too fast
Incorrect shape
Someone who is osteopetrotic has…
Massive bone XD
When a bone fractures, what cells are responsible for the healing process, and where do these cells arise from?
Osteoblasts
Arise from periosteum
What are the types of bone structures?
Give an example of each type
Long - limbs Short - tarsals, carpals Flat - skull Pneumatic - skull Sesamoid - patella Irregular - vertebrae
