Muscular System Flashcards
Origin
The bone where a muscle begins and is usually at the proximal end of the body
Insertion
The bone on which a muscle ends and is usually at the distal end of the body
Relationship between Agonist and Antagonist Muscles
For a joint to move, one muscle must contract (shorten), while another must relax and extend (lengthen)
Agonist (prime mover)
The muscle that contracts to initiate movement
Antagonist
The muscle that relaxes and extends
Helps to slows down or stop the movement in order to protect the joint from damage
Excitability
Ability to react to nerve impulses
Contractability
Ability to shorten and thicken (concentric contraction)
Extensibility
Ability to stretch or lengthen
(eccentric contraction)
Elasticity
Ability to return to original length and shape after contraction or extension
Concentric Contraction
- Muscle fibers shorten
- Origin and insertion move
closer together
Eccentric Contraction
- Muscle fibers lengthen
- Origin and insertion move
apart
Isometric Contraction
- Muscle fibers do not change in length
- Origin and insertion don’t move
Tendon
- Connective tissue (epimysium) which extends beyond the muscle & becomes a ‘strap’
- Connects to the outermost covering of the bone (periosteum)
Epimysium
- The outermost layer of connective tissue.
- It surrounds the entire muscle and blends to form a tendon.
Endomysium
- A layer of connective tissue that surrounds and separates each muscle fibre and electrically insulates it from its neighbour.
