Midterm 2 Flashcards
Bone Functions
PAAP
Provide mechanical support
Acts as a lever
Attachment sites
Protection, storage RBC formation
Epiphyseal Plate
Growth plate; when damaged can stop growth
Stress
a load applied per cross-sectional area
-how big
strain
deformation, a change from the initial length
-how long
What can affect a stress-strain relationship?
Loading, Tissue and Direction of Loading
Types of Loading
Tension, Compression, Bending, Shear, Torsion, Combined loading.
Newtons Laws of motion
LAW 1
Law I – The Law of Inertia
Every body continues in its state of rest, or of
uniform motion in a straight line, unless it is compelled to change that state by force s impressed on it.
Newtons Laws of motion
LAW 2
Law II – The Law of Acceleration
The change of motion is proportional to the force impressed and is made in the direction of the straight line in which that force is impressed.
Newtons Laws of motion
LAW 3
Law III – The Law of Action-Reaction
To every action there is always an opposite and equal reaction; or, the mutual action of two bodies upon
each other are always equal and directed in opposite directions.
Why is Bone Important?
Bone is a living Tissue
-provide a strong framework to support and protect the soft organs (such as the brain, heart, and lungs) from injury. Bone works with muscle to hold up the body when we stand and to move the body when we walk or run. Bone houses the bone marrow, which makes blood cells.
WOLFF’S LAW
our bones become thicker and stronger over time to resist forces placed upon them and thinner and weaker if there are no forces to act against.
-bone is laid down at sites where needed and reabsorbed from sites where not needed
-USE IT OR LOOSE IT
osteoclasts
-reabsorb or take up bone
osteoblasts
-lay down new bone
Osteoporosis
severe bone loss resulting in gaps in the structure
Transverse Fracture
-occurs at 90 deg angle
-caused by bending force, snaps
Oblique Fracture
-occurs sloped down/up at an angle or curve
-caused by tracing one bone while the other twists over it.
Spiral Fracture
-fracture spirals around the bone
-caused by twisting force
Comminuted Fracture
-fracture breaks into multiple pieces
-caused through crushing force
Avulsion Fracture
-ligament or tendon pulls away from its attachment on the bone and a fragment of bone breaks off with it.
-a muscle contraction or stretch that is stronger than the force that holds the tendon/ligament together.
Impacted Fracture
-occurs in the middle of the bone, driven into its self then buckles.
-caused by compression of the bone from end to end
Fissure or Hairline Fracture
-an incomplete fracture; multiple small lines are often visible, but don’t pass through the entire bone.
-caused by any force that could cause any other type of fracture, but is not great enough to completely break the bone.
Greenstick Fracture
-bone bends rather than breaks
-occurs most often in children in bones that have not completely ossified and still contain cartilage
Force
Vector quantity, mechanical interaction between an object and its surrounding. measured in newtons
Force Platform
instrument used to measure the reaction forces in 3 divisions (X,Y,Z). and moments about those 3 axis.
-limitations: mounting, altered walking patterns, conscious walking
Moment of Force
-the rotary effect of a force; also called torque. measured in newton metres nm
-clockwise rotation: negative moment
-counterclockwise rotation: positive moment
Mass
the amount of matter kg
Weight
the amount of gravitational attraction between an object and the earth
-9.81m/s2
Ground Reaction Force
the reaction force provided by the horizontal support surface.
Centre of Pressure
the point on a plane surface at which the resultant pressure on the surface may be taken to act.
isokinetic contraction
A movement in which the angular velocity of the displaced body segment is constant.
Ex- breaststroke when swimming, where the water provides a constant, even resistance to the movement of adduction.
isotonic contraction
A muscle contraction in which a muscle contracts and does work against a constant load.
EX-Isotonic exercises are any where the length of a muscle changes. Examples include bicep burls, push-ups, pull-ups, and contractions occurring in the legs while running.
Draw Force Length Graph
Draw
Draw Force Velocity Graph
Draw
Equation to find force/ weight
F = ma
Calculating moments
Find direction of force, a should be perpendicular to force, counterclockwise is positive,unit of measurement is nm Newton metres
M=Fd
Describe and explain force-length relationship
Look to notes
Describe and explain force-velocity relationship
Look to notes
