Chapter 11 - The Muscular System Flashcards
What is Movement?
Skeletal muscles produce movements by exerting force on tendons
Tendons attach to and pull on bones
Movement occurs
Point of Insertion moves
Not the Origin (Source) of the movement
What are Origin and Insertion?
Most muscles cross at least one joint and are attached at the articulating bones
When a muscle contracts, it draws one articulating bone towards the other
What is Origin?
Origin:
The attachment to the stationary bone
What is Insertion?
Insertion:
The attachment to the moveable bone
What is a Lever System and Leverage?
Levers: bones
Fulcrums: joints
The lever is acted on by:
Resistance
Effort
What is a First Class Lever?
Fulcrum between Effort and Resistance
What is a Second Class Lever?
Resistance between Fulcrum and Effort
What is a Third Class Lever?
Effort between Fulcrum and Resistance
What are the Effects of Fascicle Arrangements?
Muscle fibers are arranged in parallel bundles within fascicles but the arrangement of fasciculi in relation to the tendon can vary
Fascicular arrangement is correlated with:
Amount of power a muscle can produce
Range of motion a muscle can produce
(more fascicles = more power and ROM)
What are the different Arrangements of Fascicles?
Parallel
Fusiform
Circular
Triangular
Pennate
Unipennate
Bipennate
Multipennate
What is Parallel Arrangement of Fascicles?
Fascicles parallel to longitudinal axis of muscle
Terminate at either end in flat tendons
ex- Sternohyoid muscle
What is Fusiform Arrangement of Fascicles?
Fascicles nearly parallel to longitudinal axis of muscle
Terminate in flat tendons
Muscle tapers towards tendons, where diameter is less than at belly
ex- Digastric muscle
What is Circular Arrangement of Fascicles?
Fascicles in concentric circular arrangements from sphincter muscles that enclose an orifice (opening)
ex- Orbicularis Oculi muscle
What is Triangular Arrangement of Fascicles?
Fascicles spread over broad are converge at thick central tendon
Gives muscle a triangular shape
ex- Pectoralis Major muscle
What is Pennate Arrangement of Fascicles?
Short fascicles in relation to total muscle length
Tendon extends nearly the entire length of the muscle
What is Unipennate Arrangement of Fascicles?
Fascicles arranged on only one side of tendon
ex- Extensor Digitorum Longus muscle
What is Bipennate Arrangement of Fascicles?
Fascicles arranged on both sides of centrally positioned tendons
ex- Rectus Femoris muscle
What is Multipennate Arrangement of Fascicles?
Fascicles attach obliquely from many directions to several tendons
ex- Deltoid muscle
How does Coordination within muscle groups work?
Most muscle movements are coordinated by several skeletal muscles acting in groups rather than individually
And most skeletal muscles are arranged in opposing pairs at joints
Agonist/Prime Mover
Antagonist
Synergist
What is Agonist/Prime Mover?
Carry
ex- Biceps
What is Antagonist?
Put back after carry
ex- Triceps
What is Synergist?
Multiple muscles work together at same time
Same purpose, some pull up, some pull forward
Like Inhalation and Expiration Muscles
ex- Chest muscles
How are Muscles named?
Muscles are named based on:
Location
Size
Number of origins
Appearance
Direction of fibers
Origin and insertion
Muscle action
What is Rectus?
Parallel to midline
ex- Rectus Abdominis