The Cellular Structure Of Bone Flashcards
What are the functions of bone?
Structure, mechanical, protective, metabolic
What is the structural function of bone?
Give structure and shape to the body
What is the mechanical function of bone?
Sites for muscle attachment
What is the protective function of bone?
Vital organs and bone marrow
What is the metabolic function of bone?
Reserve of calcium and other minerals
What are the proportions of inorganic and organic bone?
65% inorganic, 35% organic
What makes up the inorganic part of bone?
Phosphorus, sodium, magnesium, calcium hydroxide
What makes up the organic part of bone?
Bone cells and protein matrix
What are the types of anatomical bones?
Flat, long, short, irregular and sesamoid
What are examples of flat bone?
Sternum/ skull
What is the function of flat bone?
Protective
What is the distinguishing structure of long bones?
Longer than they are wide
What is the function of long bone?
Allow us to make big movements
What are some examples of short bones?
Carpals in hands or tarsals in feet
What is the function of short bone?
Provide stability in joints and allow us to make smaller movements
What is the distinguishing feature of short bone?
As long as they are wide
What is the function of irregular bones?
Complex shapes that protect specific organs like the pelvis or vertebrae
What are sesamoid bones?
Embedded in muscle or tendons and act like a pulley to reduce stress
What are the two macroscopic types of bone?
Trabecular and cortical
What are the features of trabecular bone?
Thin, honeycomb-like Highly metabolic Adds strength 15-25% calcified Large SA
How much of the skeleton is made up of trabecular bone?
20%
Which bit of the bone is made up of trabecular bone?
The axial bits (Epiphysial)
What are the features of cortical bone?
Thick bone that makes up the shaft of the bone
80-90% calcified
What are the functions of cortical bone?
Mainly structural, mechanical and protective
Which bit of the bone is made up of cortical bone?
Shaft
How much of the Skeleton is made up of cortical bone?
80%
What are the two types of microscopic bone structure?
Woven and lamellar
When is woven bone usually around?
During initial bone development
Is woven bone mature or immature?
Immature
Is lamellar bone mature or immature?
Mature
In what type of bone does endochondral ossification happen in?
Long bones
In what type of bone does intramembranous ossification happen in?
Flat bones
What is intramembranous ossification?
Direct differentiation of osteoblasts from connective tissue
What is endochondral ossification?
Bones forming from a cartilage model
What bones fuse together last (and at what age)?
Clavicle growth plates at 20 yrs
How does endochondral ossification work?
Cartilage model is made in the womb.
Blood vessels invade the scaffold, bringing precursors for bone cells
Precursors differentiate into bone (called primary ossification centre)
First occurs in the diaphysis and moves towards the epiphysis
Secondary ossification centre formed in the epiphysis