Lecture 5 - Neurons and their communication Flashcards
What are the different scales of explanation in psychology?
- social group/community
- person
- brain
- neural circuits/networks
- neuron
- molecules
- synapse
describe the structure of a neuron and its components
The structure of a neuron includes:
cell body:
- contains the nucleus and all structures necessary for cell functioning
dendrites:
- receive signals from other neurons; input zone
axon:
- sends signals from the axon hillock to the axon terminals, output zone.
- wrapped in myelin for efficient transmission
Axon terminals:
- form synapses with other neurons and secrete neurotransmitters to send signals
What are the types and functions of glial cells?
The types and functions of glial cells are:
Oligodendrocytes:
- produce the myelin sheath that wraps around axons
Astrocytes:
- supply nutrients from blood to neurons and maintain the blood-brain barrier
Microglia:
- act as the brain’s immune system, cleaning up foreign or toxic substances
How do synapses function in neural communication?
synapses join the axon terminals of one neuron to the dendrites of another neuron for signal transmission. Neural signals go one way: from the pre-synaptic neuron (axon terminal) to the post-synaptic neuron (dendrite)
What are the key terms related to neuron signals and membrane potential?
Key terms include:
membrane potential:
- difference in electrical charge (voltage) between the inside and outside of the cell
resting potential:
- at rest, more positive ions are outside than inside the cell, giving an overall negative potential inside (approximately -70mV)
action potential:
- an electrical signal pulse that travels along the axon, triggered when the membrane potential exceeds the threshold
Describe the types of ion channels involved in action potentials
The types of ion channels involved are:
sodium potassium pump:
- actively pumps Na+ out and K+ into the cell, maintaining the negative resting membrane potential
voltage-dependent ion channels:
- open when membrane potential reaches threshold, allowing ions to flow across the membrane, causing depolarization and repolarization
Ligand-Gated Ion Channels:
- open in response to neurotransmitters, allowing ions to flow and change the membrane potential
How are neurotransmitters released and received in synaptic transmission?
During an action potential, depolarization of the axon terminal triggers the release of neurotransmitters stored in synaptic vesicles. These neurotransmitters cross the synaptic cleft and bind to receptors on the post-synaptic neuron, opening ion channels and passing the signal
What are EPSPs and IPSPs?
EPSPs (Excitatory Post-Synaptic Potentials):
- caused by depolarization when receptor channels open and positive ions (e.g. Na+) flow in, bringing the membrane potential closer to the threshold for an action potential
IPSPs (Inhibitory Post-Synaptic Potentials):
- caused by hyperpolarization when receptor channels open and positive ions (e.g. K+) flow out or negative ions (e.g. Cl-) flow in, moving the membrane potential further from the threshold
How does neural integration determine whether a neuron will fire an action potential?
Neural integration involves summing all excitatory and inhibitory inputs received through dendrites. If combined membrane potential at the axon hillock exceeds the threshold, an action potential is triggered, and the neuron fires
How does the loss of dopamine affect Parkinson’s disease, and what is a common treatment?
Parkinson’s disease involves the loss of dopamine in the basal ganglia, affecting movement. A common treatment is L-DOPA, which replaces dopamine in the brain
How do SSRIs and MAOIs work as antidepressants?
SSRIs (Selective Serotonin Reuptake Inhibitors):
- increase serotonin signaling by keeping serotonin in the synaptic cleft longer
MAOIs (Monoamine Oxidase Inhibitors):
- prevent the breakdown of serotonin, increasing its levels in the synaptic cleft
