Neurons are the fundamental units responsible for transmitting and processing information through electrical and chemical signals. Their unique structure allows them to communicate rapidly within the nervous system.

Dendrites are branched extensions that receive incoming signals from other neurons. They play a crucial role in collecting and processing synaptic inputs.

The axon hillock is the region where electrical signals from the dendrites are integrated and an action potential is generated if the threshold is met. It acts as the trigger zone for nerve impulses.

The myelin sheath is a fatty layer that insulates axons, thereby increasing the speed of electrical signal transmission. Its presence is vital for efficient neural communication.

The cerebellum is pivotal in regulating motor control, balance, and coordination. It integrates sensory input to fine-tune movements and maintain equilibrium.

The occipital lobe is specialized for processing visual stimuli, making it essential for interpreting what we see. Its unique structure is dedicated to analyzing aspects like color, light, and motion.

The blood-brain barrier acts as a selective filter, preventing toxins and pathogens from entering the brain tissue. This protective mechanism maintains a stable environment crucial for neuronal function.

Serotonin is critically involved in stabilizing mood, sleep, and appetite. Imbalances in serotonin signaling are frequently linked to mood disorders, emphasizing its role in emotional regulation.

The axon hillock is the site where incoming signals are summed, and if the threshold is reached, an action potential is initiated. Its role as the decision-making center is vital for effective neural communication.

The synaptic cleft is the tiny gap between neurons at a synapse. Neurotransmitters released into this gap bind to receptors on the adjacent neuron, enabling signal transmission.

The spinal cord is fundamental in conducting reflex actions, allowing for rapid responses to stimuli without the delay of brain involvement. This direct pathway ensures quick protective reactions.

Myelin acts as an insulating layer around the axon, which allows electrical impulses to travel faster by jumping between gaps known as nodes of Ranvier. This process, called saltatory conduction, enhances signal speed and efficiency.

Oligodendrocytes are specialized glial cells in the central nervous system that create the myelin sheath. In contrast, Schwann cells perform myelination in the peripheral nervous system.

Excitatory neurotransmitters depolarize the postsynaptic membrane, making it more likely to reach the threshold needed to fire an action potential. This facilitation of neuronal activity is crucial for effective signal propagation.

The thalamus serves as a central relay station for sensory and motor signals heading to the cerebral cortex. It plays an essential role in processing and directing neural information efficiently.

Synaptic plasticity refers to the activity-dependent changes in the strength of synaptic connections. This dynamic process is fundamental for adapting neural circuits during learning and memory formation.

In myelinated axons, action potentials jump between gaps in the myelin called nodes of Ranvier in a process known as saltatory conduction. This mechanism greatly increases the speed of nerve impulse transmission.

The dopaminergic system is central to the brain's reward circuitry, influencing pleasure, motivation, and addiction. Alterations in dopamine signaling are strongly implicated in addictive behaviors.

Neurotrophins are essential growth factors that promote neuronal survival, development, and differentiation. Their role is crucial during brain development and in maintaining synaptic plasticity throughout life.

The 'all-or-none principle' means that once a neuron's threshold is reached, it fires an action potential at a consistent amplitude; if the threshold is not reached, no action potential occurs. This ensures consistent and reliable signal transmission.