Address the following Short Answer prompts questions:-
1. In 4 or 5 sentences, describe the anatomy of the basic unit of the nervous system the neuron. Include each part of the neuron and a general overview of electrical impulse conduction, the pathway it travels, and the net result at the termination of the impulse. Be specific and provide examples.
2. Answer the following (listing is acceptable for these questions):
o What are the major components that make up the subcortical structures?
o Which component plays a role in learning, memory, and addiction?
o What are the two key neurotransmitters located in the nigra striatal region of the brain that play a major role in motor control?
3. In 3 or 4 sentences, explain how glia cells function in the central nervous system. Be specific and provide examples.
4. The synapse is an area between two neurons that allows for chemical communication. In 3 or 4 sentences, explain what part of the neurons are communicating with each other and in which direction does this communication occur? Be specific.
5. In 3–5 sentences, explain the concept of “neuroplasticity.” Be specific and provide examples.
References:
- Stahl, S. M. (2021). Stahl’s essential psychopharmacology: Neuroscientific basis and practical applications (5th Ed.) Cambridge University Press.
- Chapter 1, “Chemical Neurotransmission” (pp. 1-28)
- The neuron, the fundamental unit of the nervous system, consists of various components. The cell body (soma) contains the nucleus and other essential organelles. Dendrites receive incoming signals from other neurons or sensory receptors. Axons transmit electrical impulses, or action potentials, away from the cell body. Myelin sheath, formed by glial cells, covers some axons and speeds up signal conduction. Impulses travel along axons, facilitated by the opening and closing of ion channels, resulting in a cascade of depolarization and repolarization. At the axon terminals, neurotransmitters are released into the synapse, a small gap between neurons, to transmit the signal to the next neuron or effector cell, like a muscle cell, leading to a net excitatory or inhibitory effect.
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- The major components of subcortical structures include the thalamus, hypothalamus, basal ganglia, and limbic system.
- The hippocampus, a component of the limbic system, plays a role in learning, memory, and addiction.
- Dopamine and gamma-aminobutyric acid (GABA) are the two key neurotransmitters located in the nigra striatal region of the brain that play a major role in motor control.
- Glial cells in the central nervous system (CNS) serve crucial roles in supporting neurons. Astrocytes regulate the chemical environment around neurons, provide structural support, and contribute to the blood-brain barrier. Microglia are the immune cells of the CNS, protecting against pathogens and maintaining neural health. Oligodendrocytes form myelin sheaths around axons, enhancing signal transmission. Schwann cells perform similar functions in the peripheral nervous system.
- At the synapse, the communication occurs between the axon terminal of the presynaptic neuron and the dendrites or cell body of the postsynaptic neuron. Neurotransmitters released from vesicles in the axon terminal travel across the synaptic cleft and bind to receptors on the postsynaptic membrane. This communication can be either excitatory or inhibitory, influencing whether the postsynaptic neuron generates an action potential. Communication occurs in one direction, from the presynaptic neuron to the postsynaptic neuron.
- Neuroplasticity refers to the brain’s ability to reorganize its structure, function, and connections in response to experiences, learning, or damage. It encompasses synaptic plasticity (changing strength of synapses) and structural plasticity (forming new synapses or pruning existing ones). For example, in response to learning a new skill, such as playing a musical instrument, certain brain areas may undergo structural changes, forming new neural pathways. Similarly, after a stroke, unaffected regions of the brain can compensate for damaged areas by reorganizing functions.