Weight and Size: The average adult human brain weighs about 3 pounds (1.4 kilograms) and makes up about 2% of a person's body weight. Despite its size, the brain uses approximately 20% of the body’s energy and oxygen intake.
Neuron Count: The human brain contains approximately 86 billion neurons. Each neuron can form connections to thousands of other neurons, via synapses, creating a highly complex and expansive network.
Composition: The brain is about 75% water and consists of about 60% fat, making it one of the fattiest organs in the human body. It also contains proteins, amino acids, and microelements such as iron, iodine, and zinc.
Cerebral Cortex: The outermost layer of the brain, known as the cerebral cortex, is critically involved in complex functions such as memory, attention, perceptual awareness, thought, language, and consciousness. The cortex is about 2-4 mm thick and contains six layers.
Brain Development: At birth, the human brain is almost the same size as an adult brain, demonstrating its importance. The brain continues to grow and develop significantly during the first few years of life, reaching its full size around the age of 25.
Plasticity: The brain has a remarkable ability to adapt and change—a phenomenon known as neuroplasticity. This allows the brain to develop new connections and pathways, change existing ones, and adapt to new experiences, learning, and injuries.
Energy Consumption: Although the brain is only about 2% of the body's weight, it consumes about 20% of the glucose-derived energy making it one of the most energy-consuming organs.
Sleep and Brain Health: Sleep is crucial for brain health, as it helps to consolidate memories and clear out toxins that accumulate during the day. Lack of sleep can impair cognitive functions and long-term brain health.
Unconscious Brain Activity: A large amount of brain activity is unconscious, including processes that manage basic body functions such as breathing, digestion, and heart rate, as well as more complex functions like emotions and impulses.
Sensory and Processing Speed: The brain can process images that the eye sees for as little as 13 milliseconds — much faster than the blink of an eye, which takes 100 to 400 milliseconds.