The Human Brain in Good Health
A complex network of arteries, veins, and capillaries feeds and oxygenates the entire brain. The brain is separated from the rest of the bloodstream by this vascular network, which is tightly managed. The blood-brain barrier protects the brain against infection, but if it does become contaminated, it is difficult to cure since many medications have a molecular structure that is too big to pass across the barrier. This is also a key issue when looking for drugs to treat Alzheimer’s disease, as they must get past this barrier in order to reach the brain.
The temporal lobes of the brain are located behind the ears and temples. Speech and working memory are processed in these areas, as well as ‘higher’ emotions including empathy, morality, and regret. The limbic system, which is found beneath the forebrain, is a more primitive brain region. The limbic system is a mechanism found in all animals that is responsible for processing our desires and emotions. The hippocampus, which is also part of the limbic system, is important for generating new memories.
The cerebellum is located at the back of the brain and preserves our muscle memory, allowing us to perform tasks such as riding a bike without thinking. The midbrain and brain stem are the brain’s most rudimentary areas. They act as an interface between the spinal cord and the remainder of the brain, controlling basic activities such as heart rate and digestion.
All of these complex functions are mediated by synapses, which are connections between brain cells (neurons). There are approximately 100 billion brain cells in an adult human brain, each of which is connected to its neighbors by 5-10,000 synapses.
Every second we are alive, our brains develop a million new connections — a million new synapses. The strength and pattern of connections in the brain are constantly changing, and no two brains are alike.
Memories are stored, habits are taught, and personalities are shaped in these dynamic connections by reinforcing certain patterns of brain activity while losing others.
Synapses allow brain cells to communicate in a variety of ways. Signals go across the synapse in the form of neurotransmitters, which are molecules. Neurotransmitters travel from one brain cell to the receiving brain cell via a synapse (connection), where the neurotransmitter is collected by a receptor. The receiving cell can then send out another rush of neurotransmitters to relay the message to other brain cells.