Synapses and Sensory Receptors Flashcards
junction
btwn synaptic terminal and naother neuron or effector
electrical synapses
electrical current flows from one neuron to another; no neurotransmitters
chemical synapses
synaptic cleft; presynaptic neuron AP arrives at synaptic terminal depolarizes pm VG channels open Ca2+ diffuse into terminal inc Ca2+ causes synaptic vessicals to fuse w terminal mem NT released into cleft and diffuse across + bind to specific receptors on postsyn mem
synaptic cleft
gap which seperates presynaptic neurons from postsynaptic cells (20nm)
presynaptic neuron
synthesizes NT; packaged into synaptic vessicles
acetylcholine
muscles, memory, learning NT
glutamate
excitatory NT
dopamine
mood NT
endorphins
pain regulation NT
ligand gated ion channels
graded potential in postsyn; mem of postsyn cell receptor protein binds + responds to NT (ligand) opens LG channels ions diffuse across postsyn mem; postsyn potential: EPSP (mem depolarizes) and IPSE (mem hyperpolarizes)
postsynaptic neuron
some EPSE some IPSP; dendrites + cell body recieve info from many chem synapses
magnitude of PSP varies based on
amnt of NT released by prosyn neuron; distance of synapse: one single EPSE has to travel to axon hillock may be too small to trigger AP
temporal summation of postsyn potential
2 EPSP @ single synapse right after each other; interplay btwn IPSP + EPSP axon hillock integrates, mem pot = summed efect, AP threshold
spacial summation of postsyn potential
EPSPs @ same time from diff syns on same postsyn; interplay btwn IPSP + EPSP axon hillock integrates, mem pot = summed efect, AP threshold
NS embryonic dev
overal structure: regulated gene expression, signal transduction; brain continues to develop + remodel: competition amongst neurons for growth supporting factors, synapse elimination
neuronal plasticity
neuronal connections can be modified NS remodeling based on activity; remodeling occurs @synapses: connections reinforced when activity of neuron coincides w other neurons connections weaker if activity doesn’t coincide (use it or lose it)
short term memory
info briefly held released if irrelevent; stored in cerebral cortex accessed via temporary links in hippocampus; acquiring not maintaining
long term memory
info stored in cerebral cortex but connections w/i cerebral cortex
long term potentiation (LTP)
how memories are stored + learning happens; increase synaptic transmission strength; presynaptic neuron 2 conditions: high freq series of AP + AP arrives @ same time that postsyn cell gets depolarized by seperate stimulus; postsyn mem w glutamate receptors for NMDA + AMDA before LTP NMDA receptors to glutamate blocked Mg2+
during LTP
postsyn mem depolarizes; NMDA releases Mg2+; takes in glutamate NT; influx of Ca2+; AMPA receptors also activated; both work to creae postsyn potentials strong enough to generate APs
sensory pathway
ind gains info about surrounding env and internal state (sensory input); process by CNS (integration); sent to body and appropriate motor response (motor output)
4 components of sensory pathway
(1) sensory reception via sense organ: stimlus/info detected by cells + receptors (2) signal transduction: conversion of stimulus to receptor potential, change in mem pot of receptor, flow of ions across mem of receptor (3) transmission: sensory info travels through NS as impulses, APs unstim to RP stim is depolarized (4) perception: brain processes info sent to it by sensory neurons
types of sensory receptors
based on stimulus; ex: chemoreceptors, chem stim binds to sensory cell receptors changes ion permeability
gustation
taste
