1. Module 1- Skeletal Physiology Flashcards
What are bones used for?
Protection
Standing/support
Movement
Regualtion of calcium and phosphurus
Blood cell production
Defends against acidosis
Conducts sound in inener ear
How are bones classified
Long bones (e.g. humerues)
Flat bones (e.g. sternum)
Flat bones (e.g. carpal bones)
Irregular bones (e.g. vertebrea)
Sesamoid bones (e.g. patella)
What is the periosteum?
Fibrocarltilage layer of bone
Where is articualr cartilage found?
At either end of bone, allows for smooth gliding of bones
Where is yellow bone marrow found?
What is its function?
Diaphysis (middle)
Mainly contains fat cells
Where is red bone marrow found?
What is its function
Metaphysis (top)
Production of red blood cells
What are the anatomicla regions of bone
Epihysis- outer region of bone
Diaphysis- middle region of bone
Metaphyis- area between epiphysis and diaphysis
What is cortical bone?
Hard outer shell
What is trabecular bone?
lightweight network of bone foudn in the inner region
How are flat bones formed?
Begins as a fibrous plate and then differntiates fro, fibroblasts and haemopoietic precursors
There is no cartilaginous phase
Describe the formaiton of long bones
Forms as cartilage
Blood vessels invade cartilage (through osteogenic cells)
Cartilage remains in growth plate (only have epiphysis and diaphysis)
Growth plate fuses and turn into bone
What are bones made of?
48% mineral
31% organic
21% water
(roughly)
What is meant by bone minereal?
Hydroxyapatite
Provides ridgitity
How does minerealization occur?
Old bone is laid down from the edge and minerlized in the center
What is the organic section of bone made of?
Type 1 collagen
Triple helxi protein with two alpha 1 and one alpha 2 chains
Combine to make fibrils and fibrils make fibres
How is water stored within the bone?
May be foudn in pores between haversian canals
May be found loosely bound (elasticity with collagen)
Might be found tightly bound
How does the water contnet of bone change as you get older?
More loosely bound water when youre young
More tightly bound water when youre old
What are the three key cells that maintain and repair bones?
Osteoclasts- multinuclear bones. Cut bone
Osteblasts- build new bone. Works together
Osteocytes-Sensors of mechanical load. Influence osteoblasts and clasts
Where do the repair cells come from
Osteblasts and osteocytes come from mesenchymal stem cells
Osteoclasts come from haemopoietic stem cells
Describe how osteoblasts build bone
Lay down osteoid (uncalcified bone matrix)
Calcifies after around 10 days
How do osteoblasts function help with their biosynthetic function?
Rich in endoplasmic reticulum and golgi apparatus (protein synthesis)
How do osteoclasts cut bone?
Form an F actin ring within the cell to seal off the area
Use acid and enzymes to degrade the bone (dentine)
How long does the bone remodelling cycle take?
Should you know it for exams
3 months
if you know nothign else know this - Jenny G
Describe the bone remodelling cycle
Starts in stage of quiescence (bone linign cells)
State of resorbtion (osteoclasts)
Reversal stage (osteblasts recruited)
Formation (New bone synthesised) and then mineralised
Discuss bone formation throughout life
0-25- bone mass gains
25-40- bone stays stable
Old age- bone is lost
What factors impact bone mass?
Genes
exercsie
Nutrition
Calcium and vitamin D
Smoking
Oestrogen
What changes occur to bone in osteoperosis?
Reduced bone mass
Same amount of minereals and organic tissue
What bone changes occur in osteoarthritis?
Increased bone mass
Reduced minerals
Increased organic material
In osteopetrosis what changes occur in bone
Decreased resorption (increased mass)
During paget’s disease, what changes occur to bone
Increased resorption (bendy bones)
