Module One, Lecture Ten Flashcards
Muscle Form and Function at Joints (18 cards)
How does the Skeletal Muscle cause movement at Synovial Joints? ( 4 )
- Attaches to bone ( lever )
- Muscle structure ( Length, number of fibres, arrangement of fibres )
- Type of contraction ( Roles / Action )
- Where it crosses a join ( Location )
What are the three Classes of Levers? ( 3 )
- First ( Stabilises joint position )
- Second ( Effective at overcoming heavy loads )
- Third ( Large range of movement )
Example of First Class Lever…
See-Saw or Scissors ( Fulcrum between force and load )
Example of Second Class Lever…
Wheelbarrow or Bottle Opener ( Load between fulcrum and force
Example of Third Class Lever…
Tweezers or Fishing Rod ( Force between fulcrum and load )
What is the Fulcrum?
The point on which a lever rests and pivots
How does Muscle Form determine Function? ( 3 )
Depends on…
- Length of muscle fibres
- Number of muscle fibres
- Arrangement of muscle fibres
How does the Length of Muscle Fibres determine function?
If a large ROM is required = long muscle fibres
How does the Number of Muscle Fibres determine function? ( 2 )
- Tension is directly proportional to the cross-sectional area
- Greater number of fibres ( greater CSA and greater tension )
How are Muscles Fibres Arranged? ( 2 )
- Paralle
- Pennate
Describe the structure of Parallel Muscle Fibres…
Fibres arranged vertically between muscle tendons / attachments
Describe the structure of Pennate Muscle Fibres…
Fibres arranged obliquely between muscle tendons / attachments
What are the three ways a muscle can contract? ( 3 )
- Concentric
- Eccentric
- Isometric
What is Concentric Muscle Contraction?
Muscle is action and develops tension, which is greater than the load. The muscle shortens and there is a change in joint position ( e.g. Elbow Flexion )
What is Eccentric Muscle Contraction?
Muscle is active and develops tension, which is lesser than the load. The muscle elongates in opposite direction and there is a change in joint position ( E.g Elbow Extension )
What is Isometric Muscle Contraction?
Muscle is active and develops tension, which does not outweigh the load. There is no change in length of muscle or joint position ( e.g Holding the elbow join still, biceps brachii contracts isometrically )
What are the Types of Muscle Roles? ( 4 )
- Agonist ( Creates movement )
- Antagonist ( Opposes / controls movement )
- Stabiliser ( holds joints still )
- Neutraliser ( stops unwanted movement )
What are the Concentric Actions of Muscles? ( 4 )
- Medial + Adduction
- Anterior + Flexion
- Lateral + Abduction
- Posterior + Extension
Applies for all joints except for the knee