Levers Flashcards
What are the 3 types of muscle
Skeletal muscle
Cardiac muscle
Smooth muscle
Describe skeletal muscle
Works in voluntary movements
Is attached to the the skeleton to allow different movements or actions
Describe cardiac muscle
Works involuntarily
Found in the heart
Describe smooth muscle
Works involuntarily
Can be found in blood vessels and the intestines
What is the origin
The attachment to the bone by the tendon NEAREST the midline
Where the muscle joins to a stationary bone
What is the insertion
The attachment to the bone by the tendon FURTHEST from the midline
Where the muscle joins a moving bone
How do the insertion and origin move when a muscle contracts
When a muscle contracts the insertion moves towards the origin
What types of bones are the origin tendon and insertion tendon usually attached to
Origin - flat, stable bone
Insertion - attached the the bone that the muscle is pulling on
Describe the action of the skeletal muscle
Movement involves several muscles, each muscle plays a particular muscle so that each movement is controlled
Because a muscle can only pull, other muscles must be used to support and accommodate the desired movement
What are the main functions of levers
To increase the speed at which the body can move
To overcome heavy resistances with little effort
What do longer levers help with
Longer levers generate more momentum and speed
What is the function of a 1st class lever
To increase the speed of an object
What movements are 1st class levers
Tricep movements
What is the function of 2nd class levers
Moving lots of weight easily
What type of movement is 2nd class levers
Movements at the ankle/balls of the feet
What is the function of 3rd class levers
To increase the speed of the body/limb - it is not efficient in applying force
What type of movement is 3rd class levers
Everything else
Hip, knee, elbow
Define agonist
The muscle directly responsible for a movement that contracts to perform a movement
Define antagonist
The muscle responsible for supporting the movement that works with the agonist
Define fixator
The muscle used to stabilise joints during a movement
It stabilises the origin so the agonist can work effectively
Define synergist
A muscle that prevents any unwanted movements helping the other muscles to perform the desired movement
What is the mechanical advantage in 1st class levers
Neutral - the arms are equal distance from the fulcrum
What is the mechanical advantage in 2nd class levers
High - the effort arm is greater than the load arm
What is the mechanical advantage in 3rd class levers
Low - load arm is greater than the effort arm
What is the equation of mechanical advantage
Mechanical advantage = effort arm/resistance arm
Describe high mechanical advantage
EA is longer than RA
Can move a large load over a short distance, only requiring little force
Difficult to generate speed and only has a small ROM
Describe low mechanical advantage
RA is longer than EA
Cannot move as heavy a load but can do it faster with a larger ROM
