Muscular System: Chapter 6 Flashcards
muscles
comprised of fascicles
fascicles
groups of muscle fibers bound together
muscle fibers
compromised of myofibrils
myofibrils
composed of sarcomeres
sarcomeres
composed of actin and myosin (contractile proteins)
tendon
connects muscle to bone
musculotendinous junction
where muscle meets tendon
tenoperiosteal junction
where tendon meets bone
origin
where the muscle starts (more on the stationary bone)
insertion
where it ends
oblique
- shorter, more numerous
- Greater potential for strength
- Produces smaller ROM
parallel
- longer
- greater potential for shortening
- produces greater ROM
strap muscles
long, thin fibers running length of muscle
fusiform muscles
- spindle shape
- widest in the middle
- tapers on both ends
- fibers still run the entire length of the muscle
- biceps, brachialis, brachioradialis
triangular muscles
trapezius or pectoralis major
Sub category for oblique muscle oriented fibers
- unipennate
- bipennate
- multipennate
pennate muscles
- feather arrangement
- oblique fibers attached to tendon
unipennate
bipennate
- on central tendon
- oblique oriented fibers on either side
- (rectus femoris)
multipennate
- multiple tendons
- oblique fibers sit in between each tendon
- (deltoid)
muscle tissue properties
- irritability
- contractility
- extensibility
- elasticity
irritability
ability to response to a stimulus
contractility
ability to generate force with sufficient stimulus
extensibility
ability to lengthen
elasticity
ability to return to resting length (recoil)
sliding filament theory
- describes the interaction between actin and myosin
- muscle receives stimulus to contract
muscle receives stimulus to contract and what happens?
- myosin heads reach out, bind to actin filaments, and pulls them together
- this causes the sarcomere to shorten
all sarcomeres of a muscle fiber shorten _____________
simultaneously
sarcomeres shorten the __________ _________
entire muscle
optimal length
- slight stretch
- max interface between actin and myosin
- some passive tension present
- increases the force generating capacity
a muscle is able to shorten to _______ its resting length
half
a muscle is able to lengthen _____ times its resting length
1.5
agonist
prime mover
- performs the movement
antagonist
performs the opposite movement of the agonist
co contraction
agonist & antagonist contract at the same time
synergist
a muscle that works in conjunction with another to perform the same action
passive insufficiency
- a multi-joint muscle cannot lengthen any further without damage
- occurs to the antagonist
- ex: hamstrings stretched with hip flexion and knee extension
active insufficiency
- a multi-joint muscle cannot shorten any further due to length
- occurs to the agonist
- ex: hamstrings shortened with hip extension and knee flexsion
tenodesis
- utilizes the principle of passive insufficiency
- allows for opening/closing of the hand in Pt’s with spinal cord injuries
muscle contractions
- concentric
- eccentric
- isometric
- isokinetic contractions
concentric contraction
muscle shortens as it contracts against gravity
eccentric contraction
muscle lengthens and decelerates against gravity
isometric contraction
muscle length stays the same during contraction
isokinetic contractions
- speed of motion stays the same throughout the contraction
- resistance changes in order to maintain speed
- ex: biodex
open chain
distal segment is not fixed
closed chain
distal segment is fixed
