Human Disease YR3 #1 Flashcards
(498 cards)
What is the function of an osteoblast?
It forms bone
What is the function of an osteoclast?
It resorbs bone
What differentiate to form osteoblasts?
Mesenchymal progenitor cells
What differentiates to form osteoclsts?
Myeloid progenitor cells
Name 5 cell signalling ligands stimulate the activity of osteoblasts?
TNFaIL-1IL-11PTHPGE2
What do osteoblasts release to activate the differentiation of osteoclasts?
RANKL
What vitamin is essential for bone health?
Vitamin D
Explain the 4 steps in the cycle of vitamin D formation in our body?
- Photons from sun hit skin2. 7DHC is activated and travels to the liver3. At the liver it is converted to 25(OH)vit D (then stored)4. It then travels to the kidney and becomes 1,25(OH)2 vit D (physiologically active)
What ion is essential for bone formation/turnover?
Calcium
If Ca is low what occurs?
Bone resportion
If Ca is high what occurs?
Bone formation
What are the 5 main substances that aid the control of Ca metabolism? and which organs?
Ascorbic acidVit DCaPTHPO4
BoneGIParathyroid glandKidneyLiver
What is the definition of Paget’s disease of the bone?
Localised disorder of bone turnoverIncreased bone resorption followed by increased bone formationLeading to disorganised bone: bigger, less compact, more vascular and more susceptible to deformity and fracture
How is Paget’s disease of the bone transmitted?
Genetically (15-30% familial)Anglo-Saxon originsChronic viral infection within osteoclasts
What are the symptoms for Paget’s disease?
> 40 age with bone painBone deformityExcessive heat over pagetic boneNeurological complications such as nerve deafness
What are the presentations of Paget’s disease?
Isolated elevation of serum alkaline phosphataseBone pain and local heatBone fracture or deformityHearing loss
What is the treatment for Paget’s disease?
Surgical intervention (hard if asymptomatic)Don't treat if raised alkaline phosphatase aloneIV bisphosphonates therapy with one off IV zoledronic acid
What is the difference between Rickets and Osteomalacia?
Rickets - before the epiphyseal lines are closed| Osteomalacia - adult disease
What is the definition of Rickets and Osteomalacia?
A severe vitamin D or Ca deficiency causing insufficient mineralisationMuscle function is also impaired in low vit D states
How are vitamin D and Ca related?
Vit D stimulates the absorption of Ca and PO4 from the gut and Ca and PO4 then becomes available for bone mineralisation
What is the presentation of Rickets?
Stunted growthCurved spineWide joints at elbow and wristCurved legs (splayed)Wide bones and ankles
What are the symptoms for Osteomalacia?
Aches and painsInability for muscle coordination Waddle gaitStruggle out of chair
Treatment for Osteomalacia and Rickets?
Ca and vit D supplementation
What is the definition of osteogenesis imperfecta?
Genetic disorder of CT characterised by fragile bones from mild trauma or everyday acts