1.1. Neurons Flashcards
What is the foundational concept of neuroscience regarding the central nervous system?
Specific sets of interconnected neurons are responsible for all behavioral functions in the brain.
Who conducted pioneering studies on the anatomy of neurons in the Central Nervous System (CNS) at the turn of the 19th century?
Ramon y Cajal, a Spanish scientist, used Golgi’s silver staining method.
What is the “Neuron doctrine,” and what are its key principles as developed by Ramon y Cajal?
The “Neuron doctrine” includes three key principles: a) Neurons are separate/individual cells; b) Electrical signals flow in one direction (principle of dynamic polarization); c) Nerve cells make specific connections (principle of connectional specificity).
What are the three anatomical and functional parts of a neuron?
A neuron comprises dendrites (input), soma (metabolic center), and axon (output).
Describe the initiation of action potentials in a neuron.
Action potentials are initiated at the axon hillock, a specialized trigger region at the origin of the axon.
How does the myelin sheath contribute to action potential conduction?
The myelin sheath, produced by Schwann cells or oligodendrocytes, insulates large axons, increasing the speed of action potential conduction. Nodes of Ranvier ensure regeneration and maintain constant amplitude.
What is the role of synapses in neuronal communication?
Synapses are special zones where neurons communicate. Neurotransmitters released at synapses transfer information from one neuron to the next.
Explain the process of neurotransmission at a synapse.
When an action potential reaches the presynaptic terminal, vesicles containing neurotransmitters fuse through exocytosis. Neurotransmitters bind to receptors on the postsynaptic membrane, causing excitation or inhibition.
What is the significance of dendritic spines in neurons, and how are they involved in synaptic plasticity?
Dendritic spines increase synaptic surface area and are plastic structures that change volume and shape in response to stimuli. Their shapes correlate with synaptic strength and memory formation, contributing to processes like motivation, learning, and memory.
What electron-dense region is found at the tip of dendritic spines, and what role does it play?
The tip of dendritic spines contains an electron-dense region called “postsynaptic density” (PSD), housing ion channels and neurotransmitter-gated receptors. This region is crucial for synaptic transmission and integration.
