About 2 million years ago, a human brain was half the size of today's human brain. Your brain controls everything about you: breathing, thought, movement and interaction with others. Animals have brains that look similar to the human brain in most respects, but they behave differently, with less sophisticated intellectual systems. According to Your Amazing Brain website, the differences are most likely due to the process of evolution.
History
Brain growth starts with a neural plate that develops at 16 days of pregnancy. Gradually, a neural tube grows, the front areas become the brain and the rest develops into the spinal cord. By the seventh week, an embryonic human brain divides into fore, mid and hind brains, according to the University of Washington. At birth, you have a billion brain cells, almost all you will ever need. Rapid development over the first two years of life links the neurons together with connections that govern your physical and mental development.
Identification
The average adult brain weighs a little over 3 pounds. The bones of your skull protect it, and it connects with your spinal cord through a hole in the base of your skull. This allows messages to pass to your whole body. The gray surface or cortex of your brain folds in on itself, making efficient use of the available space. Underneath lie white neural fibers, and between the brain and the skull are tough protective membranes called meninges.
Function
Areas in your brain manage different activities. The limbic system, deep in your brain, maintains your survival instincts and emotions. Your cerebellum, at the back of your head, coordinates your actions. Your central brain stem regulates the systems that keep you alive, including breathing, heart rate and blood pressure. The cortex, divided into a left and right brain, contains the frontal lobes, responsible for personality, temperament and behavior, and the parietal lobes, governing sensory impulses and motor activity. The temporal lobes are important in language, memory and smell, while the occipital lobes regulate your vision.
Features
As a baby, you learn fast. Your brain connections develop during critical periods of growth, according to Growing Child website, as protective myelin sheaths gradually cover your neural connections. After the critical period, you find it harder to acquire new skills. Your occipital lobes develop most during the first three or four months after birth. Most language skills appear in the first three years, although development continues until age 10. Motor skills continue to develop until around 12 years old.
Considerations
According to scientist Fred Gage, old suppositions that no damaged brain cells replace themselves were mistaken as cells in the hippocampus, part of the limbic system involved in involuntary behavior, do regenerate. Damage to other parts of the brain remains pretty much irreversible.
