bones, cartilage ligaments, tendons, muscle Flashcards
What are the two main types of bones
cancellous (spongy 30-90% porosity)
cortical (compact 5- 30% porosity)
Name the functions of bones
movement, support, organ protection, blood cell production, mineral storage.
1) Osteoblasts 2)osteoclasts
1) lay down new bone, 2) remove old/ damaged bone.
What loads can bones experience
axial compression, tension, torsion, shear, bending.
Wollf’s Law
Bone remodels in response to stress and strain.
Major types of joints
fibrous (immovable), cartilagenous (semi-movable), synovial (freely movable)
Primary components of synovial joint
Articular cartilage, joint capsule, synovial membra,e. synovial fluid, associated ligaments.
Main functions of tendons and ligamenst
Tendons- connect muscle to bone (transmit force), ligaments- connect bone to bone (stabilise joints)
Muscle tissue
Cardiac (heart), skeletal (voluntary movement), smooth (involuntary organs)
Sliding filament theory
muscle contraction occurs when myosin heads pull actin filaments, shortening the sarcomere.
stress strain graph in bone
Elastic region (linear region)- the bone deform elastically as it can return to its original shape when load is removed. This represents the stiffness of the bone.
Yield point- the bone reaches maximum elastic deformation, microcracks may start forming.
Pastic region- the bone deforms permanently and absorbs energy through plastic deformation.
Ultimate Strength- the highest point on the graph- maximum stress the bone ccan withstand before failing.
Fracture point- the bone completely breaks at this point.
Cortical bone is more brittle and fractures at lower strains, Cancellous bone can sustain higher strains
Gross anatomy of tendons and ligaments
Tendons and ligaments are strong and stiff. Tendons prevent excessive elongation when muscles contract (efficient force transmission from muscle to bone).
Ligaments restrict excessive joint movement, preventing dislocations and maintaining stability.
They both act as a shock absorber, tendons store and release energy and ligaments protect joints from sudden forces preventing injuries.
Smooth surfaces- collagen fiber structure, reduction of friction when gliding over bones and muscles, efficient movement without excessive wear.
White in appearance- high collagen contant low blood supply meaning they heal slowly after injury.
Viscoelasticity
Description of how tissues respond to applied forces in a manner that combines both elastic (spring like) and viscous (fluid- like) properties. Materials in which stress and strain are time dependant are said to be that
Biomechanical properties of tendons
The tendon behaves elastically under low loads, becomes stiffer as it is streched more and begins to fail under high loads and eventually rupture when loads exceeds its ultimate stregth.
