Neuromuscular Control Flashcards
What is resting membrane potential
-70mV (if you don’t get this, just leave)
cytosol has what charge relative to ECF
negative
what goes in a cell?
K+
what goes out
Na+ and Cl-
membrane potential causes neurons and myocytes to:
receive info
transmit info
integrate info
how much is needed to open Na-K Pump?
10-15mV
Depolorization makes membrane become?
+30mV
what happens when K+ out
hyperpolarizes
what determines nerve conduction velocity?
fiber size and presence of myelin
how does a larger diameter affect nerve conduction velocity?
less resistance, faster conduction
What does myelin do?
speeds conduction from 200m/s
Excitatory Post-Synaptic Potentials
Na+ increased
Inhibitory Post-Synaptic Potentials
Na+ decreased, Cl- increased
what is the basic functional unit of skeletal muscles?
motor units
what happens with motor unitys with smaller neuron cell bodies
recruited first
How does the thalamus control movement?
contains relay pathways from cerebellum, basal ganglia, superior colliculus to motor cortex
contributes to motor generation and self-monitoring
how does the hypothalamus control movement?
regulates internal environment to maintain homeostasis; temp, BP, HR, contractility, respiration, digestion, fluid balance, emotion, neruodocrines, sleep-wake, appetite, thirst
how does the cerebellum control movement?
receives visual and proprioceptive input; compares actual movement to motor plan; generates corrective responses
coordinates the timing and sequencing of mus activity, smoothing movement
how does the brain stem control movement?
autonomic regulatory centers for respiratory and cardiovascular centers;
reticular system- coordinates mus fxn, maintains mus tone, contributes to sleep-wake and consciousness, pain control
Sensory System
transmits info from sensory organs, skin, blood and lymph, tendons, and muscles to central somatosensory areas.
Motor System: Pyramidal
corticospinal and coritcobulbar tracts
innervate motor neuron in spinal cord and brainstem
involved in voluntary movement.
Motor System: Extrapyramidal
primarily located in reticular formation; modulated by cortex, cerebellum, basal ganglia, involved in reflexes, postural control, and coordination of movement
Sympathetic NS
fight fight fight or flight
control HR, vasculature, and respiration
Parasympathetic NS
feed and breed
promotes synthesis of glycogen
Neuromus physiological adaptation due to resistance training
- increase motor unit firing rate
- increase motor unit recruitment
- increase motor unit synchronization
- increase reflex neural facilitation
- increase coordination of antagonist mus
- inhibition of Golgi tendon organs (autogenic inhibition)
Neuromus functional result of resistance training
- increase rate of force development
- increase force production and duration
- increase force producation and efficiency
- increase rate of force development*
- disinhibits max contraction
contractile adaptation: physiological response to resistance training
- increase mus mass
- increase CSA
- increase type II fiber area
- increase intracellular lipid contact
- increase ATP utilization rate
contractile adaptation: functional result of resistance training
- increase strength
- increase contractile capacity
- increase strength (selective recruitment)
- increase metabolic capacity
increase max contraction capacity
Elastic Adaptations to Resistance Training: Series Elastic Components
- tendons and myocytes crossbridges
- translate stretch into force
Elastic Adaptations to Resistance Training: Parallel Elastic Components
- collagenous structures
- stabilize and protect muscle
Elastic Adaptations to Resistance Training: stretch-shortening cycle
stretch creates potential energy that can enhance forces produced by contractile elements
Hypertrophy
protein is degraded when subjected to mechanical overload
stims molecular pathways that favor protein syn
this increases the size and amount of contractile elements and #sarcomeres in parallel
augments diameter of individual fibers resulting in an INCREASE IN CROSS SECTIONAL AREA and strength
What happens to excess protein
oxidized –> urea formation –> dehydration and diuresis
Hyperplasia
overload may stim proliferation of myocytes from satellite cells
overload
mus tension must be developed at adequate intensity and duration
immobilization
changes occur within hours
- decreases in protein synthesis
- loss mus mass and contractile/SR
- 3-4% strength loss daily in first week
Aging
mus mass peaks b/n 25-30 yo
loss ~8% per decade
fiber atrophy, fiber loss, motor unit remodeling
