Finals Study Flashcards
what is the structure breakdown of skeletal muscle
muscle(with epimysium) -> fascicles -> fibres -> myofibrils (actin and myosin)
what are the 3 major functions of skeletal muscle
stores protein (metabolism)
movement and force generation (electrical -> mechanical)
thermogenesis
what are the 4 properties of skeletal muscle
excitable/irritable
contractile
extensible
elasticity
what are the 8 factors that affect torque
- activation history
- cross-bridge function and energetics
- size
- type
- elasticity/passive stiffness
- neural activation/innervation
- mechanics/attachments
- antagonist balance
what are the 2 component types of skeletal muscles
contractile components, and protein components
what are the contractile components of muscle
actin and myosin
what are the protein components of muscle
collagen and elastin -> make epimysium (muscle) perimysium (fascicles) and endomysium (fibres)
what are the 6 roles of proteins
support contractile components
transmit force
resist stretch
mechanotransducers
protein metabolism
gene transcription
what is included in the hill model (1938)
sarcomere, passive and elastic elements (elastic includes in series and parallel, both of with are contractile)
is high elasticity good or bad? why?
good because high elasticity = more purposeful/controlled movement, low elasticity = jerky movements
what is NMJ
chemical amplification of AP to depolarize
what is ACh
secreted and binds to receptors on muscle -> depolarizes at membrane -> broken down by ACH esterase for Na channels to receive info
what is E-C coupling
excitation-contraction -> depolarization to muscle to make force (aka electrical to mechanical transduction)
what are the 2 types of force output determinants
intrinsic and extrinsic
what are the 5 intrinsic force output determinants
size, shape, pennation/architecture, adaptability, and type/composition
what are the extrinsic force output determinants
anything outside of individual muscle (aka neurons, fatigue/history, antagonists, etc.)
in series vs parallel
in series = direct, increased ROM, and faster
parallel = lower ROM, but increased force
what in the benefit of increased pennation
stronger force total (less per fibre) because more fibres acting
what are the components of the motoneuron
soma, synapse, spinal cord, axon, axon hillock, dendrites
what is the soma
the cell body
what is the synapse
the electrical/chemical junction
what is the spinal cord
regionalization aka UMN to LMN
what is the axon
LMN (to muscle)
what is the axon hillock
control center, chooses whether or not to send AP
what are dendrites
to muscles (afferent)
what are the 8 steps of AP firing
- negative potential
- excitation threshold reached
- Na -> cell
- Na in and K out (depolarization)
- K out and increased membrane potential
- K out and Mp normal (repolarization)
- K and N channels close
- K diffuses away (hyperpolarization)
what is absolute vs relative refractory
absolute = cannot send AP
relative = harder to send AP
what is the order of conductance
K < Na < MP
what is synaptic pots
input that does not reach the threshold
what is rate coding
pattern and frequency of impulses
what is the point of myelination
myelin increases conductance and speed, AP is re-energized at nodes
