Neurophysiology Flashcards
Action potential
the release of a neurotransmitter
membrane moves ions via?
passive transport when moving into the cell
active transport at rest
sodium potassium pump
3 sodium out, 2 potassium in
electrical gradient
attraction of opposite charges
chemical gradient
flow of ions down concentration
excitatory post synaptic potential
brings us closer to threshold by bringing in NA+
Inhibitory post synaptic potential
brings us away from threshold by letting in CL ions
graded potentials
can depolarize or hyperpolarize cell,
effects of axon diameter
larger diameter, faster impulse
effects of myelination
makes everything faster
Group A fibers
somatic sensory and somatic motor
large diameter, heavily myelinated
fasts, 300mph
Group B fibers
Autonomic
medium diameter, nonmyelinated
30mph
Group C fibers
Autonomic NS
small diameter, nonmyelinated
slow, 2mph
Absolute refractory period
no stimulus can activate another potential
Relative refractory period
another action potential is possible but must overcome hyperpolarization
Synaptic transmission
Transmission across the synaptic cleft is a chemical event that involves release, diffusion, and binding of neurotransmitters. The action potential of +30 mV arrives at the axon terminal of the presynaptic neuron. Opens voltage-gated calcium channels. Calcium binds to Synaptotagmin protein and fuses synaptic vesicle with axon membrane. Neurotransmitters diffuse and bind to receptors on the postsynaptic neuron. The ion channels open causing that second neuron to either inhibit or have an action potential. Within a few milliseconds the neurotransmitter is terminated either by breaking it down, reuptake by putting it back where it came from, or diffusing it away from the synaptic cleft.
Dopomine
neurotransmitter found in CNS
can plead to addiction
parkinsons disease
synaptotagmin
protein that binds with Ca++ and promotes fusion of synaptic vesicles with axon membrane
Serotonin
associated with mental and emotional disorders
etc. depression, OCD, bipolar, anxiety, migraines
Exteroceptors
stimuli outside the body
Interoceptors
stimuli in internal organs
Proprioceptors
stretch in joint tissue