1/23 Neuronal basics Flashcards
Resting membrane potential
Excess positive outside, excess negative inside (-70mv).
Gradients at rest
K out, Na in. Pump to bring K in and Na out. Keeping the membrane hyperpolarized.
Action Potential flow
Depol to threshold, voltage gated Na open = rush of depol in, Volt gated K open = pos rush out to hyperpol.
Axon Conductance and Transport
Saltatory conductance. Anterograde proteins using kinesins, retrograde metabolic needs using dynein
Pathway tracing?
Use dye anatomically. Or use andromic spikes for physical evidence, a positive collision test means you don’t see a spike moving down axon later because the two collided. Negative collision test means you see it because they aren’t connected so didn’t collide
Electrical synpase
Gap junction, fast, ions freely flow
Chemical synapse
axodendritic, axosomatic, axoaxonic. synaptic cleft using neurotransmitters/vesicles. Excitatory EPSP or inhibitory IPSP.
Neurotransmitter types
amino acids (glutamate/gaba), amines (norepinepherine/dopamine), acetylcholine, peptides (larger)
Gating mechanisms at chemical synapses
Ligand-gated = receptor is the effector, ionotropic, opens with NT
G-Protein Coupled = receptor is not effector, metabotropic, NT bind causes effector protein (g) to open the channel
Methods to monitor neurons
Extracellular (spikes, no AP look like), Intracellular (look like AP), Extracellular (look like AP), Muscle Junction (endplate potential), Electromyogram (emg)
Neuronal circuits 3 classes
Sensory, inter, motor
Transduction?
Transduce physical stimulus to nerve impulses
Four qualities of stimulus encoded by sensory system
Modality (sub ones too), location, intensity, duration
How determine intensity
Neurons have threshold, and adapt, becoming less sensitive over time (opponency)
Important aspects of location
size/shape/fine detail
