Bone Flashcards
what cell could develop into osteoclast or osteoblast
stem cells
what are osteoblast
(成骨细胞)cells that form new bone tissue, synthesize collagen, add mineral crystals
what are osteoclast
(破骨细胞)cells that break down bone tissue
what is bone density used to describe?
amount of bone mineral in bone tissue
what is bone mass used to describe?
amount of bone tissue in the skeleton
what is the mechanical loading of bone?
mechanical forces that are exerted on bone through force and through the contractile activity of muscle. These physical forces serve to maintain or gain bone mass and may also improve bone structure通过力和肌肉的收缩活动施加在骨骼上的机械力。这些物理力量有助于维持或增加骨量，也可能改善骨结构
what can mechanical loading of bone do?
These physical forces serve to maintain or gain bone mass and may also improve bone structure这些物理力量有助于维持或增加骨量，也可能改善骨结构
what is the abbrvation of PTH represents for
Parathyroid Hormone甲状旁腺激素
what is PTH function
control calcium levels in your blood
what name for vitamin D3
Cholecalciferol胆钙化醇
what does calcium to do with bone health
functions in the mineralization of bone in forming the crystal lattice
在骨骼矿化形成晶格的过程中起作用
protein and bone health
forms organic bone matrix
▪ 50% of volume of bone
vitamin D and bone health
promotes calcium absorption in gut, regulates serum calcium and phosphorus concentrations and is critical to process of differentiation
促进肠道钙吸收，调节血清钙和磷浓度，对分化过程至关重要
vitamin A and bone health
regulates activities of osteoclasts and osteoblasts
调节破骨细胞和成骨细胞的活动
magnesium and bone health
functions in the mineralization of bone in forming the crystal lattice
在骨骼矿化形成晶格的过程中起作用
phosphorus and bone health
-functions in the mineralization of bone in forming the crystal lattice
在骨骼矿化形成晶格中起作用
fluoride and bone health
promotes mineral precipitation leading to the formation of apatite which is deposited within the organic matrix促进矿物沉淀，形成磷灰石，磷灰石沉积在有机基质中
vitamin K and bone health
activates vitamin K dependent proteins identified in bone: osteocalcin and matrix Gla protein
骨中发现的维生素K依赖蛋白:骨钙素和基质玻璃蛋白
how many different minerals could help form crystal lattice in mineralization
Calcium, magnesium, phospgorus
3 proteins bone tissue
collagen osteocalcin(骨钙蛋白) matrix gla progein(MGP)
what is cortical bone
dense outer bone; on the surface and shaft of all bones,
layers of mineralized protein (mostly collagen)
counts for 75-80% of total bone
what is trabecular bone
spongy appearance, internal scaffolding, supports cortical bone; high in vertebrae, and joints; susceptible to loss海绵状外观，内部支架，支撑皮质骨;脊椎和关节高的;易受损失
Consists of an interconnected system of mineralized proteins (mostly collagen)由一个相互连接的矿化蛋白质系统(主要是胶原蛋白)组成
counts for 20_25% of tatal bone
how would you describe that bone tissue is dynamic?
- remodeling: ongoing turnover and repair of microfractures(Vk and Va)
- physical stress enhances bone formation
- factors that causes bone loss: bed rest and lack of weight bearing environments(space travel)
- age determines balance of process(成骨细胞活力相对于破骨细胞的下降)
bone density is modeled by成骨细胞&破骨细胞
overall view of bone mass
▪ Total weight of bone tissue in body
▪ Affected by age, sex, genes, exercise, nutrition
▪ Key nutrients are Vitamin D, Calcium, Magnesium,
Phosphorus
▪ Optimal time for bone formation is adolescence (90%
formed by 16 years)
overall view of bone density
▪ Compactness of the crystals (minerals)
▪ Strength of bone tissue
▪ Measured routinely to determine osteoporosis
▪ Densitometry reflects calcium status (calcium is
always 39% of total body mineral)
what’s the main organic component of bone tissue and gives the bone its flexibility
collagen:
counts for 90% of bone matrix is collagen
scaffolding
collagen and biochemstery
Normal collagen requires amino acids (hydroxylysine, hydroxyproline, Vit C)
why Vc is important for collagen?
Normal collagen can be mineralized
▪ Deficiency of Vit C (ascorbic acid) can cause poor mineralization
overall view for osteocalcin(骨钙素)
▪ Non collagenous protein
▪ Made by osteoblasts during bone matrix formation
▪ Synthesis stimulated by Vit D
▪ Using Vit K-dependent carboxylation
▪ Increased fractures with low levels of carboxylated osteocalcin
低水平羧化骨钙素增加骨折
▪ Bone derived hormone骨源性激素
▪ Found in bones, teeth
▪ Facilitates binding of Ca+ to hydroxyapatite lattice
what cell could produce osteocalcin
made by ostroblasts(成骨细胞) during bone matrix formation
synthesis stimulated by VD,
Vk dependent carboxylation, low level of carboxylated osterocalcin would increase fracture(骨折)
what are the mineral structures in bone
Formation of hydroxyapatite:Ca10 (PO4)6 (OH)2
what’s the optimal dietary ratio of Ca:Phos?
2:1
what nutrients could affect formation of bone mineral structure
Vd, phosphorus, magnesium, fluoride
how to build mineral stability?
- Fluoride: stabilizes hydroxapatite and forms fluorapatite by replacing the OH
- Binding to osteocalcin requires Vit K
- Evidence suggests that fluorapatite may be more resistant to dental decay and theoretically more resistant to osteoporosis有证据表明，氟磷灰石可能更能抵抗蛀牙，理论上也更能抵抗骨质疏松症 how ever, adequate intake for reduction dental caries also shown to ↑ bone density & lower fracture risk, But bone tissue may be of poorer quality at ↑ fluoride intake :▪ Excess Fl may lead to very large crystals which can increase fragility
vaitamin D
