Anatomy Chapter 9 Skeletal Muscle Fibers
The function of the muscle upon contraction
Action
Responsible for producing a particular movement
Agonist
Actions oppose the action of the agonist
Antagonist
Examples of parallel muscles
Biceps brachii, rectus abdominis
Muscle fibers are on both sides of the tendon
Bipennate
2 methods of describing muscle actions
Bone region, joint
Muscle fibers form concentric rings (sphincter muscles)
Circular
Muscle fibers form a broad area but come together at a common point
Convergent
Examples of multipennate
Deltoid muscle
Unipennate example
Extensor digitorum
Examples of Circular muscles
Orbicularis oris, orbicularis oculi
Point of muscle attachment that remains stationary
Origin
Muscle fascicles are parallel to the longitudinal axis
Parallel
Examples of convergent
Pectoralis major
Muscle fibers form an oblique angle to the tendon of the muscle
Pennate
Fibers associated with the leg muscles
Slow fibers
Fibers that have small diameter, take a while to contract, last long intervals, have a lot of myoglobin, and use aerobic metabolism
Slow fibers
Red fibers
Slow fibers
Fibers associated with back and legs
Slow, intermediate
Assist the action of the agonist
Synergist
Primemover is Biceps brachii, what is the antagonist?
Triceps brachii
All the muscle fibers are on the same side of the tendon
Unipennate
Examples of bipennate
rectus femoris
Fibers associated with eye muscles
Fast fibers
Fibers associated with eyes and hand
Fast fibers
Fibers that are large in diameter, large in glycogen reserves, few mitochondria, fatigue easily but are very powerful
Fast fibers
Fibers that use anaerobic metabolism
Fast fibers
White fibers
Fast fibers
Antagonist and agonist muscles contracting at the same time to stabilize a joint
Fixators
Primemover is Biceps brachii, what is the fixator
Flexor and Extensor muscles
Point of muscle attachment that is movable
Insertion
Running long distance increases proportion of ___fibers
Intermediate
Fibers that have low myoglobin but high glycogen, use anaerobic metabolism, lots of mitochondria and resist fatigue
Intermediate fibers
Pink fibers
Intermediate fibers
Primemover is Biceps brachii, what is the synergist
Latissimus dorsi, teres major
The tendon branches within the muscle
Multipennate