L.3 - bones Flashcards
What are the 5 functions of bone?
- Support
- Framework for attachment of soft tissue and organs. - Leverage
- Bones function as levers that can change the magnitude and direction of force is generated by skeletal muscles. - Protection of organs
- skull, ribs, spine. - Storage of minerals and lipids
- calcium (the parathyroid gland releases hormones which cause bones to release calcium) - Blood cell production
- red and white blood cells are produced in the red marrow
How many bones are there in the adult human Skelton?
- 206
In how many broad categories can the 206 bones of the body be categorized? State them.
- 6 categories
- Flat bones
- Long bones
- Short bones
- Irregular bones
- Sesamoid bones
- Sutural bones
Give examples of flat bones?
- scapula
- sternum
- cranium
Give examples of long bones?
- femur
- humerus
- tibia
Give examples of short bones?
- carpals
- tarsals
Give examples of irregular bones?
- vertebrae
- mandible
Give examples of sesamoid bones?
- patella
Give examples of structural bones?
- small, flat, and irregular bones of the skull
What are the 2 types of bones?
Compact or cortical bone - solid bone
• forms the sold outer shell and shaft (diaphysis) of long bones)
Trabecular, cancellous, or spongy bone - network of trabecular struts
• commonly found at the end (epiphyses) of long bones
What are the 2 phases of bone composition?
Organic phase and inorganic phase
What are in the organic and inorganic phases on bone composition?
Organic
• type 1 collagen - in bone. like rubber (very pliable - easily bent)
• collagen - 25% of weight of bone
Inorganic
• calcium hydroxyapatite- crystals that offer compressive strength to the bone
• bone mineral - 60% of weight of bone
Water & ground substance is also part of bone composition !!!!!!
What is a bone?
- a living tissue which has a blood supply and nerves
What cells are distributed throughout the bone(bone cells)?
- mechanosensing cells called osteocytes
What are osteocytes and what do the do?
- bone cells
- these cells detect changes in their physical and chemical surroundings and release chemicals in response causing bone to removed or formed
What will happen to materials when force is applied?
- deformation (change of shape)
What does deformation depend on?
- size of the force
- area over which the force is applied
Force per Unit area (N/m^2)
What is the equation of force/stress on a material?
sigma symbol = F/A
Sigma symbol = stress in a material
A= cross sectional area
F = force
What are the 3 common types of stress applied to the bones and tissues within the human body?
- compression
- tension (stretching)
- shear stress
What is a strain (reaction)?
- when a material of length (L) is subjected to compressional or tension so stress, a change of length (🔺L) occurs.
- the resulting strain (ع) is defined as the fractional change in length of the material (therefore ع has no units)
What is elastic deformation?
- within the elastic region of the graph (up to point B) deformation is elastic and the material will still red your to its original shape when the force is removed.
What is Young’s Modulus? What is the equation?
- symbol = E
- is the ratio of stress to strain (Nm^-2)
- is the slope of the stress-strain graph in the linear region up to point A
- it is a measure of stiffness or rigidity.
E = o / ع
Ratio of stress to strain = stress / strain
What does high Young’s Modulus indicate?
- stiff material
For small values of stress and strain (up to point a) the graph is a straight line which means …?
- strain is linearly proportional to stress
- material obeys Hooke’s Law (F ~ 🔺L)