ARU Neurophysiology Response Discussion – Description
please respond to Katrina with 150. words.
Katrina
Discussion #2:
Placing the process of neuronal communication into your own words is a great way to fully understand the process. Therefore, using your own words, respond to the following items.
1) Define resting membrane potential and the difference between excitatory postsynaptic potentials (EPSPs) and inhibitory postsynaptic potentials (IPSPs).
There is a lipid bilayer that surrounds a neuron that has ion channels as a way for ions to pass in and out of the neuron. The difference in charge between the inside and outside of the neuron is membrane potential. Inside a neuron when at rest is negatively charged at -70 mV. The difference in concentration of negatively charged ions inside and positively charged ions on the outside result in the resting membrane potential. EPSP creates an environment at the postsynaptic site that has the potential to fire an action potential, through excitatory neurotransmitters. Examples include glutamate and Aspartate ions. These ions create an excited environment by opening the ligand-gated ion channels, which results in positively charged ions to flow into the neuron. Starting the process of an action potential. IPSP creates an environment opposite at the postsynaptic site where there is an inhibition of firing an action potential, through inhibitory neurotransmitters. Examples include glycine and GABA. These ions create an inhibited environment by opening ligand-gated ion channels for Chloride ions (Cl-). Since chloride ions are negatively charged they cause hyperpolarization at the postsynaptic membrane, instead of depolarizing the membrane. This process prevents the generation of an action potential. EPSP moves toward the threshold level and IPSP moves away.
Sources:
https://courses.lumenlearning.com/wm-biology2/chapter/resting-membrane-potential/Links to an external site.
https://www.differencebetween.com/difference-between-epsp-and-vs-ipsp/Links to an external site.
2) Describe how the forces of diffusion and electrostatic pressure work collectively to facilitate electrochemical communication.
Diffusion, a concentration gradient from high to low, and electrostatic pressure, the force of two ions with similar charge to repel and opposite charge to attract, work together to balance the environment of the neuron. They have an inversely proportional relationship. This is done to achieve resting membrane potential, so the environment of the neuron will allow for a new action potential. For example, the membrane is permeable to potassium at rest. So the inside of the cell has a high concentration of K+, while diffusion is a gradient it will push K+ outside the cell. Alternatively, electrostatic pressure pushes K+ into the cell due to the negative charge within, since opposing charges attract. The opposite could be said about chloride and sodium’s relationship with diffusion and electrostatic pressure as well. Opposing until resting membrane potential is met and the neuron is ready for another action potential.
Sources:
https://nobaproject.com/modules/neurons#:~:text=Diffusion%20pushes%20K%2B%20outside%20the,another%20with%20respect%20to%20K%2BLinks to an external site..
https://www.britannica.com/science/gas-state-of-matter/DiffusionLinks to an external site.
3) Explain the action potential and the features of synaptic communication in neurons.
An action potential is an all or nothing electrical signal that is conducted down the axon when the membrane potential reaches the threshold of excitation. The place where the axon terminals of one neuron comes in close contact with the dendrites or soma of another neuron is defined as the synapse. Axon terminals classify as presynaptic and dendrites/some classify as postsynaptic sites. At the synapse is where the action potential causes the release of neurotransmitters in order to communicate with another neuron(s). This communication can either be chemical or electrical signals.
Sources:
https://www.brainfacts.org/core-concepts/how-neurons-communicate#:~:text=Neurons%20communicate%20using%20both%20electrical,from%20neurons%20to%20other%20cell
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