Section: 2 Flashcards
What’s the “All or none Law”?
A muscle fiber contracts to the fullest extent or not at all
What are contractions of skeletal muscles?
- Skeletal muscles contract only if stimulated
- Contracts according to the graded strength principle
- Produce movement by pulling on bones
- Muscles that move a part do not lie over the part, they lie proximal to it
- Muscles almost always act in groups rather than by themselves
What’s A muscle fiber that contracts to the fullest extent or not at all
“All or none law”
What’s the continual or partial contraction of a muscle? (Muscle fibers take turn contracting)
Muscle tone
What’s the prime mover?
Muscle or muscles whose contraction actually produces the movement
What’s the antagonist do?
Muscles that relax while the prime mover is contracting to produce the movement
What’s the synergist?
Muscle which contracts at the same time as the prime mover
A cooperative organ
What is is the strength of a muscle contraction determined by?
- Length of the fiber
- Metabolic conditions-food and oxygen
- Number of fibers involved in contraction
- Size of the load
What is the contracting element?
Myofibril
What are proteins of Myofibril?
Actin and myosin
What are actin and myosin arranged into?
Myofilaments
What do “Z” discs do?
Divide each Myofibril into linear series called sacromeres
What’s a muscle that contracts at the same time as the prime mover?
A cooperative organ
Synergist
What is a muscle whose contraction actually produced the movement?
Prime mover
What is a muscle that relaxes while prime mover is contracting to produce the movement?
Antagonist
What do these determine??
- Length of the fiber
- Metabolic conditions- food and oxygen
- Number of fibers involved in contraction
- Size of the load
Strength of a muscle contraction
What’s a Myofibril?
Contracting element
What is actin and myosin?
Myofibril proteins
What is arranged into Myofilaments?
Actin and myosin
What divides each Myofibril into linear series called sacromeres?
“Z” discs
What is the attachment to a bone that serves as a relatively fixed basis of movement?
Origin
What’s is insertion?
Point of attachment to the bone which is moved
What is origin?
Attachment to a bone that serves as a relatively fixed basis of movement
What is the point of attachment to the bone which is moved?
Insertion
What’s muscle tone?
Continual or partial contraction of a muscle. (Muscle fibers take turn contracting)
What is rectus?
Refers to straight muscle fibers
What’s an adductor?
Muscle that will pull toward the mid-line of the body
What’s a sphincter?
Refers to any muscle that closes an opening
What refers to straight muscle fibers?
Rectus
What refers to any muscle that closes an opening?
Sphincter
What refers to the muscle that will pull toward the mid-line of the body?
Adductor
