Term 1 Exam: Muscular System Chapter 11 Flashcards
What three traits are found in all muscles?
- origin
- insertion
- primary action
What are the two muscle attachment sites?
- Origin (doesn’t move)
2. Insertion (moves towards origin during contraction)
How do skeletal muscles cause movement?
- muscle exerts force on tendons
- tendons pull on bones or other structures
What is the origin site?
Attachment of tendon to the stationary bone
What is the insertion site?
attachment of the muscle’s other tendon to the movable bone
What is the belly of a muscle?
the fleshy portion of muscle between tendons
What is the primary action of the muscle?
-the main movement(s) that occur during contraction (eg flexion or extension)
What is Reverse Muscle Action (RMA)?
when action of the muscle is reversed and the positions of origin and insertion are switched
What is a lever system?
Lever is a rigid structure that can move around a fixed point called a fulcrum
What two forces act on a lever?
- the effort - causes movement due to contraction
2. the load or resistance that oppose movement
motion occurs when the _____ applied exceeds the ______or_____
effort, load or resistance
There are three types of levers, name them.
Include the position of the fulcrum, effort and load for each type
- First class lever - not common
- fulcrum is between the effort and the load - Second-Class lever (less common)
- load is between the fulcrum and efford - Third class lever (most common)
- Effort is between the fulcrum and the load
What are five patterns that fascicles form with respect to tendons?
- parallel
- fusiform
- circular
- triangular
- pennate (unipennate, bipennate, multipennate)
What does the power of a muscle depend on?
total cross-sectioned area NOT length
Most skeletal muscles are arranged in ______ pairs at the ______
include example
opposing (antagonistic)
joints
eg flexors and extensors
What is the agonist?
The prime mover
-Muscle that is responsible for action when it contracts
eg the biceps brachii is an agonist that causes flexion of the elbow joint
What is the antagonist?
the muscle that opposes the action of the agonist
eg the triceps brachii is the antagonist to biceps brachii
What is the synergist? (3)
- Muscle that assist the agonist or prime mover
- Prevents unwanted movement of other joints
- Contraction stabilizes intermediate joints
Provide an example of a synergist
muscles that flexes the fingers (prime movers) cross the intercarpal and radiocarpal joints (intermediate joints). Synergistic contraction of the wrist extensor muscles allows the hand to form a fist without flexing the wrist
What are fixators?
Muscles that stabilizes the origin of the agonist so that the agonist is more efficient
eg when muscles of the arm contracts, the scapula must be held steady
What are 8 criteria for naming muscles?
- orientation of muscle fibres
- Muscle attachment to site
- Specific body region
- Muscle shape
- Muscle size
- Muscle heads/tendons of origin
- Muscle function or movement
- Muscle position at body surface
Provide an example for each of the following muscle naming criteria:
- Shape
- Location
- Attachment
- Size
- Orientation
- Relative position
- Function
- Shape = rhomboids, triceps, biceps
- Location = intercostals (between ribs)
- Attachment= temporalis, nasalis
- Size = maximus (largest), brevis (short)
- Orientation = Rectus (straight), oblique
- Relative Postition = Lateral, internal, medial, sub-
- Function = adductor, levator (lifter), flexor, pronator
