Muscles and Movement Flashcards
What are the 3 types of muscle?
Cardia (involuntary & striated) Smooth Muscle (involuntary & non-striated) Skeletal Muscle (voluntary & striated)
What is a sarcomere?
The repeating unit between two Z-lines
What is the sequence of skeletal muscle structure
Skeletal muscle - Fascicles - Muscle fibres - Myofibrils - Actin & Myosin microfilaments
Why does skeletal muscle look ‘striped’ when viewed histologically?
Overlapping actin & myosin
What happens at a histological level when a skeletal muscle is “strained” / “pulled”?
Some of the muscle fibres are torn
What are the different types of skeletal muscle (5)
- Circular - orbicularis iris
- Pennate - deltoid
- Fusiform - biceps brachii
- Quadrate - rectus abdominus
- Flat with aponeurosis - external oblique
Under what condition can skeletal muscle move a joint?
If they span it, i.e. have to cross the joint
Attach to bones before and after the joint
During contraction, skeletal muscles….
shorten
Muscles (usually) attach to bone via…
tendons
What is an aponeurosis?
A flattened tendon
What are flattened tendons most commonly associated with?
Flat muscles
What are the points of attachment of a muscle to a bone called
Origins and insertions
The only thing a skeletal muscle can do is…
contract, i.e. muscle fibres shorten along the long axis between the origin and insertion
The action(s) of a muscle are determined by…(4)
- the joints spanned
- long axis of the muscle fibres
- aspect(s) of the spanned joint(s)
- shapes of the articular surfaces of the join(s), i.e. limits to movement in any direction
Which joints does the biceps brachii span and which movements does it cause? (3)
Anterior shoulder joint - flexion
Anterior elbow joint - flexion
Anterior proximal radioulnar joint - supination of the forearm
Which joint (1) does the deltoid muscle span and which movements does it cause (3)?
Crosses the shoulder join
Posterior fibres - extension
Middle fibres - abduction
Anterior fibres - flexion
Usually skeletal muscles are named according to a combination of…
shape / location / size / main bony attachment / main movement