Lecture 9 - Muscles As Levers Flashcards
What are the components of a rigid skeleton necessary for locomotion
Connective tissue, tendons, ligaments and the contractile and series-elastic components of muscle
What does connective tissue divide within a muscle
Muscle fibres
What s connective tissue extended beyond the muscle known as
A tendon
What is tension in a muscle generated in
The sarcomere
How is tension in a sarcomere transmitted to the bone
Through the tendon
What type of elasticity does connective tissue have
Passive
What is the series-elastic component composed of
Extracellular titin, connective tissue and tendons
What is the series-elastic component
The build up of tension within the sarcomeres being passed onto the tendon and allowing movement of the bone
What is the area in which the muscle attaches to the stationary part of the skeleton
Origin
What is the area in which the muscle attaches to the active part of the skeleton
The insertion
When a muscle contracts what does it affect in a joint
Its structure
What is a single twitch composed of
A lag phase, tension phase and a relaxation phase
Once an action potential has been fired what must happen to the membrane before another can be fired
It must return to rest membrane potential
What must happen for a muscle to shorten during contractions
The tension developed in the muscle must exceed the forces that oppose movement of the bone to which the muscle’s insertion is attached
What are the two types of muscle contraction
Isotonic and isometric
Isotonic contraction
The muscle tension remains constant as the muscle length changes
Uses of isotonic contractions
Body movement and lifting objects
What type of muscle contraction moves the tongue
Isotonic
What is prevented during isometric contractions
Shortening of the muscle
What are the two types of isotonic muscle contraction
Concentric and eccentric
What is a concentric muscle contraction
When the muscle shortens under a load
What is an eccentric muscle contraction
When a muscle lengthens under a load
What is happening to the muscle fibre in eccentric contractions
It is resisting the stretch
Synovial joint labelled
Bony articular surface Hyaline cartilage Ligaments Synovial membrane Capsule Joint cavity
What is the function of the synovial membrane
It lubricates the joint and provides nourishment for the cartilage
What is the function of the capsule
It holds the joint together
What does the synovial membrane do
It produces the synovial fluid
What does the articular cartilage do
It protects the bone and cushions any impact
Where are intrinsic ligaments
Within the capsule
Where are extrinsic ligaments
Out with the capsule
What is the function of the ligaments
To hold the bones together and prevent unwanted movement
What is a lever
A rigid structure capable of moving around a pivot point known as a fulcrum
In the body what functions as levers, fulcrum and providing force
Bones are levers, the joints are the fulcrum and the muscles provide the force
Levers that use a small amount of force to move a large mass have
Mechanical advantage
What are the four parts to a simple lever
A lever arm, pivot, effort and load
How are levers classified
In the way in which the joint or muscles are attached to the bone and how they are arranged around the pivot
Class one levers
The pivot lies between the effort and the load
What classes of levers have mechanical advantage
Class one and two
Class two levers
The load is between the pivot and the effort
Class three levers
The load is further away from the pivot than the effort
What do class three levers provide
Larger and greater speed of movement
What can lever systems provide
Either strength or speed but not both
What is the pivot arm
The distance from the fulcrum to the upwards force
What is the load arm
The distance from the fulcrum to the load
