Neurophysiology Flashcards
Information is transmitted from the axon terminals of one neuron
the presynaptic neuron
to the dendrites and cell body of the next neuron across synapses
the postsynaptic neuron
Presynaptic Membrane: on the axon terminal of the presynaptic neuron
Postsynaptic Membrane: on the dendrite or cell body of the postsynaptic neuron
Synaptic Cleft: the gap that separates the membrane
synapses have three components
small spheres in presynaptic axon terminals that contain a neurotransmitter, a specialized chemical
- Neurotransmitters are released in response to electrical activity in the axon (when the cell “fire”)
Synaptic Vesicles
in the postsynaptic membrane are specialized proteins that react to neurotransmitter molecules
Neurotransmitters Receptors
refers to the continual remodeling of neuronal connections
Neural Plasticity (or neuroplasticity)
meaning there is a difference in electrical charge between the inside and outside of the cell
A resting neuron is polarized
electrically charged molecules
-are dissolved in fluid
Ions
negatively charged (e.g., Cl-)
Anions
positively charged (K+)
Cations
Fluid inside the cell
intracellular fluid
fluid outside the cell
- separated lipid bilayer cell membrane
extracellular fluid
inserted into a neuron will show that the interior is more negative than the exterior (this means there are more negative ions inside the cell than outside)
microelectrode
about -65 millivolts (mV)- the negative sign indicates that the cells interior is more negative than the outside
resting membrane potential
- Selectively Permeable Ion Channels
- Diffusion
- Electrostatic pressure
- Sodium-Potassium Pump
things that work together to contribute to this membrane potential
- Large proteins that span the membrane of the cell and allow some ions to pass in and out
- Some are semi-permeable and open all the time (e.g., K+)
→ this is called selective permeability, as some ions are allowed to move in and out, but not others
- Some are gated and open in response to something
Ion Channels
opens when a specific molecule binds to the receptor
Ligand-Gated
- Diffusion
- Electrostatic Pressure
Two Opposing Forces Drive Ion Movement
causes ions to spread towards a uniform concentration, along a concentration gradient
diffusion
