Neuromuscular Control Flashcards
What helps to maintain the resting membrane potential?
- negatively charged cytosol
- K+ intracellularly
- Na+ and Cl- extracellularly
Alterations in resting membrane potential are how neurons and myocytes:
receive, transmit, and integrate info with themselves and other cells
Depolarizing is to:
make less negative by opening Na+ channels
Repolarizing is to:
make more negative by opening K+ channels and inactivating Na+ channels
Hyperpolarizing is to:
make more negative than threshold by K+ channels still being open and Na+ channels in resting state
What determines the velocity at which APs are propagates along cell membranes?
fiber diameter and presence of myelin
A larger fiber results in:
lower resistance so faster conduction
Presence of myelin results in:
AP skip from node to node (saltatory conduction) and speeds conduction
What are graded potentials?
potentials in post-synaptic membrane that are proportional to stimulus strength
How are graded potentials propagated? APs?
GP: ion channels
AP: voltage gated Na and K channels
Where can graded potentials occur?
any membrane region that receives sensory stimuli
What motor units are recruited first?
those with smaller neuron bodies–type I
What neurotransmitter is released at the NMJ?
Ach
What does the thalamus contain?
relay pathways from cerebellum, basal ganglia, and superior colliculus to motor cortex
What does the thalamus contribute to?
motor generation and self-monitoring
What does the hypothalamus regulate?
internal environment to maintain homeostasis
-temp, BP, HR, contractility, respiration, digestion, fluid balance, emotion, neuroendocrines, sleep, thirst
What does the cerebellum do?
- receive visual and proprioceptive input
- compare actual movement to motor plan
- generate corrective responses
- –coordination and sequencing muscle activity
Function of brain stem:
autonomic regulatory centers for respiratory and cardiovascular centers
Functions of reticular system (brain stem):
- coordinate muscle function
- maintain muscle tone
- contributes to sleep-wake and consciousness
- pain control
Function of peripheral sensory system:
transmit info from sensory organs, skin, blood and lymph vessels, tendon, and muscle to central somatosensory areas
What receptors of the peripheral sensory system help transmit info?
- mechano
- thermo
- noci
- photo
- chemo
What tracts are part of the pyramidal motor system?
corticospinal and corticobulbar
Function of pyramidal motor system:
innervate motor neuron in spinal cord and brainstem
-involved in voluntary movement
Where is the extrapyramidal motor system located?
reticular formation of brain stem
