Muscle Structure/Function Flashcards
Name the two types of contractile proteins that make up a muscle.
Contractile proteins - shorten muscle fiber and generate active force
- Actin
- Myosin
Name the two types of non-contractile proteins that make up a muscle.
Non-contractile proteins - Support the structure of the muscle fiber
- Titin: provides passive tension
- Desmin: stabilizes alignment of adjacent sarcomeres
True/False Fusiform muscles are longer and therefore generally able to generate more force when compared to pennate muscles.
False: Fuciform are longer, however, pennate have more numerous fibers per given area=greater strength/greater force production
Agonist is the muscle which helps a body part move in a given direction, where the antagonist has the opposite action and resists the action of the agonist. The agonist for elbow extension is_______ the antagonist for elbow extension is ________.
Elbow extension is agonist = triceps
Antagonist for elbow extension is = biceps
What is synergist muscles?
An example of synergistic muscles are what?
Synergists: muscles that cooperate during the execution of a particular movement
-FCU & FCR during wrist flexion
A force couple is when two muscles simultaneously create force in _________ linear directions but produce a torque in the _________ direction.
Different
Same
Give example of force coupling muscles working on the pelvis.
Erector spinae pull posterior pelvis up and iliopsoas pulls anterior pelvis downwards (opposite directions but same anterior pelvic tilt)
A muscle contracting but not moving is an example of what?
When is this type of muscle activation useful?
Isometric (internal =external torques)
-Useful for early post-op rehab
A muscle contracting and shortening in length is an example of what?
Concentric Isotonic movement
- Acceleration activity
- Internal>external Torque
A muscle contracting and increasing in length is an example of what?
Eccentric Isotonic movement
- Deceleration activity
- Internal < external
A machine which adjusts resistance based off the force produced by the individual to ensure they move at a preset speed is an example of what type of contraction?
Isokinetic
______ type of muscle contraction places the most stress on the muscle and tendon.
Eccentric movement
What is tension within a muscle?
Force built up
Active tension comes from
contractile units (muscle generating force)
Passive tension comes from
Stretching (elastic forces produced by non-contractile proteins)
Total tension =
combination of active and passive tension
Tone -
slight tension in muscle at all times (states of readiness)
Our ideal resting length is the area in the ROM of a muscle is one in which the muscle has the ________ number of cross bridges.
Length that allows the greatest number of cross bridges
Putting a quick stretch on a muscle just prior to contraction will create the potential for ________ force production.
greater
True/False: Muscles spanning 1 joint may not have sufficient excursion to allow joint to move through entire ROM
False:
Muscles spanning 1 joint have sufficient excursion
Muscles spanning 2 joints may not
____(low/high) levels of passive tension in muscles that cross multiple joints
High
Passive insufficiency and active insufficiency are concepts only of _____ joint muscles.
2 joint muscles
_______ insufficiency is the limitation in ROM of a muscle when the muscle is placed on stretch at both joints it crosses.
Passive (flex wrist, fingers straight, but when you ext wrist your fingers will flex)
_______ insufficiency is the limitation in ability to produce force when a muscle is actively contracting at both joints it crosses.
Active (Wrist straight = strong fist, when flex wrist can’t create same force with fist)
Max torque greatest at what point of flex/ext?
Least at what point of flex/ext
Greatest - midrange
Least - full flex or ext
The ______ the load the ______ the speed of concentric contraction.
- greater the load the decreased the speed
- Smaller the load the larger the speed
The ______ the load the ______ the speed of eccentric contraction.
- Larger the load the larger the speed
- Smaller the load the smaller the speed
When attempting to stretch a one joint muscle must be aware that may need to place the two joint muscle on ______ in order to maximize the stretch at the one joint muscle.
2-joint muscle placed on slack to stretch the 1-joint muscle
(straight leg for gastroc stretch, bent knee for soleous stretch)
