extra credit 2

action potential main ionic currents

Na channels open, Na flows in → depolarization

K efflux causes repolarization

Cl influx hyperpolarization

EPSP/IPSP

EPSP - graded depolarization increases likelihood of action potential (Na or Ca influx) ex: Glutamate, ACh

IPSP - graded hyperpolarization (Cl influx or K efflux) decreases likelihood of AP ex: GABA

spatial summation/temporal summation

spatial: multiple @ same time (one big spike)

temporal: repeated in rapid succession that combine (spike increases)

homeostasis vs equilibrium

homeostasis maintains approx constant internal conditions but requires energy unlike equilibrium

Dermatome/Myotome/Sclerotome

dermatome - skin; sensory fibers that enter spinal nerve root

myotome - muscles; motor fibers that enter spinal nerve root

sclerotome - bone; specific spinal vertebrae

synaptic relay for spinal reflex (general)

transfer of sensory information from one neuron to next relay nuclei

stimulus → fibers increase firing rates → interneurons/motor neurons send signal → spinal cord → efferent motor neuron → muscle response

interneurons integrate sensory input + coordinate polysynaptic reflexes (inhibit/activate multiple muscle groups)