histopathology part 1 Flashcards
Describe the bone organisation and compositoin (leave out articular surfaces) add image
In diaphysis, there will be the main marrow cavity or medulla(contains bone marrow), surrounded on both sides by cortical bone in the cortex with the periosteum on the outside. Metapyhsis during growth will contain the cartilage structure known as the growth plate and is the region in long bones that contains the bulk of the trabecular or cancellous bone.
What are the secondary causes of osteoporosis?
Drugs Systemic disease
What type of ossification leads to the formation of: a. Long Bones b. Flat Bones
a. Long bones Endochondral ossification b. Flat bones Intramembranous ossification
Describe the histology and parthophysiology of osteoporotic bone.
Trabecular bone :Weak trabecular bridging ,Holes and cysts and thinning of bone(affects trabecular bone to most because it is the most metabolically active)
Cortical bone: thining, and there will be low impact fragility fractures in the long bones.
there is an imbalance in bone remodelling meaning there is more resorbtion than formation
What are the consequences of hyperparathyroidism to the blood and to the bone
Hypercalcaemia (increased Ca2+ reabsorption) Hypophosphataemia (increased phosphate excretion in the urine) Osteitis fibrosa cystica (due to increased osteoclast activity-Resorption of bone and replacement with fibrous tissue and the formation of cysts like ‘brown tumours.)
Describe structures you would find at articular surfaces
end of a long bone has an articular surface at a synovial joint. Smaller articular surfaces may be called facet joints or fovea. If they are knuckle shaped they are Condyles, and a trochlea is grooved like a pully
Fovea refers to a small depression or dip in the surface, such as on the femoral head where the fovea serves as a ligament attachment point.
In which ethnicities is Paget’s disease rare?
Asian African
Other than the anatomical classificaton , according to shape, ho else can bones be classified
Trabecular (cancellous) or compact (cortical)[Different macroscopic bone structures] ,Woven (immature) or lamellar (mature)[Different microscopic bone structures]
What are the indications for bone biopsy?
Evaluate bone pain or tenderness. Investigate abnormality seen on X-ray .For bone tumour diagnosis. To determine the cause of unexplained infection To evaluate therapy.
What are the three types of bone cell?
Osteoblast – build bone by laying down osteoid Osteoclast – multinucleate cells of the macrophage family that resorb bone Osteocyte- mechanosensory network,embedded in mature bone
Which sites does Paget’s disease most commonly affect?
Skull ,Sternum, Spine, Humerus, Pelvis, Femur, Tibia
Which cells produce RANKL and what is its effect?
Pre-osteoblasts It stimulates the maturation of osteoclasts
What cytokine is important for stimulating the differentiation of osteoclast precursors into pre-osteoclasts?
M-CSF (this is produced by osteoblasts)
Where are osteocytes found?
Lacunae
What are the three stages of Paget’s disease?
Osteolytic Osteolytic-osteosclerotic Quiescent osteosclerotic
