chapter 9 part 2 Flashcards
sliding filament theory
muscles contract and active and myosin slide toward each other
-zone overlap increases
-z lines get closer together
-a band width DOES NOT CHANGE
-sarcomere shrinks
(during contraction in this theory)
step by step contraction
- impulse down from nerve axon
- acetylcholine is released at the end of the axon (released at the motor plate!!)
- sarcoplasmic reticulum releases stores calcium
- calcium binds to troponin to reveal tropomyosin because the troponin complex rotates
- actin binding sites are exposed and myosin heads bind to them
journey of ACh
-synaptic vesicles must fuse to the membrane to release it
-binds to receptors
-sodium enters the cell to begin new action potential
-ACh estrace enzyme removes ACh from its binding sites
junction fold
increases surface area
precise control
eyeballs
-neurons with 2-3 muscle fibers
less precise
leg or arm
-neuron with over 2000 muscle fibers
what does lifting heavier object do?
increases the number of motor neurons you use
muscle ton
the tension when the muscle is relxed
-decreases with atrophy
muscle spindles
specialized muscle cells/ detectors watched over the sensory nerves
effects of excersize
-increase mitochondria and myofibrils
-increase muscle spindle activity
hypertrophy
increase muscle size
-hypo lypo
skeletal fiber types
fast fibers, intermediate, and slow
fast fibers
-white
-anaerobic metablosim
-places like the hand/eye
-easily fatigued
-more glycogen
intermediate fibers
-pink
-more myoglobin thanh fast
-increase glycotic enzyme
-anaerobic metabolism
slow fibers
-red
-leg muscles
-smaller; fatigue less
-lots of myoglobin
-long periods of time (marathon)
myoglobin
-gives muscle red color
fiber arrangements
-parallel
-convergent
-pennate
-circular
parallel arrangemnet
fascicle and longitudinal axis are parallel (bicep)
convergent arrangement
-fibers converge at a common point (pecs)
pennate arrangemnet
-create an angle that is oblique with muscle tendons
-can be unipennate (same side as tendon)
-bipennate (both sides of tendon) (femur)
-multipennate (tendons braching with muscleO
circular
sphincter
origin
muscle attachment area tha ti sstationary
insertion
point of attachment that is MOVEABLE
action
function of the muscle when it contracts
-2 ways
-bone region
-joint associated
groups based on actions
-prime mover
-antagonist
-synergist
-fixators
prime mover
produce specific movements
-agonis
antagonist
opposite the agonist
synergist
help the prime mover preform actions
fixators
antagonist and agonist contract at the same time to stabalize
-hold out your hand is stable
-tricep and bicept brachii
aging
-less glycogen
-less myoglobin
-less myofilaments
-fibers get smaller
-less myosatellites
-more fibrous connective tissue= fibrosis
