Chapter 11- Muscles Flashcards
What is the summarised structure of skeletal muscle?
Skeletal muscle is made up of bundles of muscle fibres which contain myofibrils which contain myofilaments of two types: actin and myosin
What is the thickness of myosin?
Thick
What is the thickness of actin?
Thin
What is the structure of a myofibril?
- H zone: only myosin
- A band: area of myosin
- I band: only actin
- Sarcomere: Z long to Z line
What happens to a sarcomere when muscles contract?
They sarcomere shortens and the myofilaments slide over one an other.
What are antagonist muscles?
Two muscles that move bone in opposite directions.
What is an example of antagonist muscles?
Triceps and biceps
What is the origin of a muscle?
The end of the muscle that is fixed to the bone that is stationary during contraction.
What is the insertion?
The end of the muscle attached to the movable bone.
What is the agonist?
A muscle that causes a desired action.
What is an example of an agonist?
Biceps when bending arm.
What is a synergistic?
Muscles that help the agonist.
What is a fixation muscle?
A muscle that stabilises one part of the body during movement of another.
What is muscle tone?
Maintaining the partial contraction of skeletal muscles.
What is an example of muscle tone in action?
The head is held up by the partial contraction of the neck muscles.
