The human brain, a remarkable weighing about three pounds, is the most complex structure known in the universe.

This intricate comprises roughly 86 to 100 billion neurons, or brain cells, each making thousands of connections to others, forming a vast communication network essential for cognition, sensation, and movement.

Despite its small size relative to the body, the brain demands about 20% of the body's energy, underscoring the vitality of the neurons within. Understanding the astonishing characteristics and functions of brain cells reveals a deeper appreciation of the brain's astounding capabilities.

Brain Cells Are Constantly Renewed and Rewired

Contrary to previous belief, certain parts of the brain continue to produce new neurons throughout life, a process called neurogenesis. This primarily occurs in the hippocampus, the center for memory formation, and in the striatum involved in movement and reward processing. This renewal is closely linked with the natural death of older neurons, and the balance between cell death and neurogenesis is critical for maintaining brain function. Evidence from animal studies indicates that when the programmed death of neurons is inhibited, fewer new neurons are integrated into the brain, suggesting a regulatory mechanism that ensures brain plasticity and functionality.

Neuroplasticity, the brain's ability to change its structure and function, relies heavily on the dynamic remodeling of synaptic connections between neurons. This plasticity allows humans to learn, adapt to new experiences, and recover from injury. Synapses—the junctions where neurons communicate—can strengthen or weaken, appear or disappear, based on activity and experiences. This constant reshaping means the brain is not a static but one that evolves throughout life, enabling learning and memory formation.

The Electrical Speed and Power of Neurons

Neurons communicate through electrical impulses called action potentials, which can travel at speeds comparable to Formula 1 cars—up to 100 meters per second. This rapid transmission enables immediate processing of sensory information and swift motor responses. Remarkably, all the electrical activity generated by the brain's neurons can collectively power a small light bulb, highlighting the energetic intensity with which brain cells operate. These impulses allow the brain to perform complex tasks, from simple reflexes to elaborate cognitive functions.

Specialized Structure of Brain Cells

Neurons are distinct in their highly specialized structure, consisting of three main parts: the cell body (which contains the nucleus and metabolic machinery), dendrites (branched extensions that receive signals), and axons (long fibers that transmit signals to other neurons). This architecture facilitates the efficient flow of information within the brain’s extensive network. Additionally, the composition of the brain is about 73% water, which supports the biochemical processes essential for neuron function and communication.

Exercise and Learning Impact Brain Cell Health

Physical exercise is known not only for its systemic health benefits but also for its enhancement of brain cell function. Exercise increases blood flow to the brain, delivering more oxygen and nutrients necessary for neuronal health and facilitating the production of chemicals that encourage neurogenesis and synaptic plasticity.

As a result, cognitive functions like memory, attention, and problem-solving improve following physical activity. Additionally, the formation of new neural pathways during learning emphasizes how actively brain cells adapt and grow in response to environmental stimuli.

Dr. Michael W. Gramlich (Auburn University): “We've found that neurons use a type of natural force based on entropy - like an invisible glue - to keep their connections strong. And when this process stops working correctly, it may be an early sign of Alzheimer's disease.”

The brain's extraordinary complexity lies in its network of billions of neurons capable of rapid electrical communication, continuous renewal, and lifelong adaptability. Brain cells not only transmit signals at incredible speeds but also constantly remodel their connections, driving the capacity to learn, remember, and respond to the world. Maintaining brain health through activities like exercise enhances the vitality and plasticity of these cells.