ILS3_ the muscular system Flashcards
What are the components of the muscular system (3)
muscle, tendons, motor unit
What’s a tendon?
tough, flexible, cord-like, fibrous connective tissue that connects muscle to bone
What are the functions of the muscular system (4)
produce skeletal movement, maintain posture and body position, regulate the opening and closing of bodily orifices, maintain body temperature
What’s a fascile?
It’s a bundle of muscle fibers in the skeletal muscle
What’s a muscle fiber?
A single cell muscle (the cell of the skeletal muscle)
What’s a myofibril?
Multiple myofibril create a muscle fiber
What’s a myofilament?
It’s the actual protein component of the muscle. It contains the sarcomere. They are the contractile components of the Muscle
Sarcomere definition
repeating, contractile units of a skeletal muscle fiber
A sarcomere is a myofilament (thick filament- myosin “contractile”) in between Z-discs (thin filament - actin)
What happens when there’s a contraction in the muscle?
the length of the sarcomere shortens and the myofilaments overlap
What happens when there’s a relaxation in the muscle?
The length of the sarcomere increases and a decrese in the myofilament overlap
What’s an isometric contraction?
- load applied withtout changing the joitn angle
- no change in muscle length
- no movement
- the muscle is contracting
What’s an isotonic (Concentric) contraction?
- decrease in muscle length
- decrease in joint angle
What’s an isotonic (Eccentric) contraction?
- Increase in muscle length
- increase in joint angle
(slows down the movement)
Epimysium definition
dense connnective tissue surrounding the entire muscle organ (envelops the outside of our skeletal muscle)
Perimysium definition
connective tissue surrounding skeletal muscle fascicles (bundles of muscle fibers)
Endomysium definition
connective tissue surrounding individual muscle fibers (myofiber)
What is fascia?
a sheet or band or fibrous connective tissue that envelops, separates, or binds together structures such as muscles, organs and other soft tissues
How does the muscle move?
the muscle moves by pulling on the bone (at the insertion) to move the joint which will make the movement
Origin of a muscle
is more proximal because usually no movement
insertion of a muscle
is more distal because it’s the moveable attachment
agonist definition
“prime mover”, concentric contraction
antagonist definition
controls, slows or resists the agonist, eccentric contraction (opposite as agonist)
synergist definition
additional muscle that assist in the agonist function
