The brain is a complex organ responsible for controlling our thoughts, movements, and bodily functions. In a healthy brain, billions of neurons and glial cells work together to transmit electrochemical signals and support the brain’s functions. However, when the brain is injured, disruptions to these natural processes can create a cascade of problems.

The brain and spinal cord are enclosed within protective membranes called the meninges. The average human brain contains billions of neurons and glial cells, which support the work of neurons by providing nutrients and oxygen and removing harmful debris. Microglia are the brain’s primary immune cells, and astrocytes perform many functions, including producing energy and helping to form the blood-brain barrier. The blood-brain barrier is a protective shield of cells that separates the brain from the circulating bloodstream.

Tau proteins in neurons serve as a support scaffolding for the axons, which transport important cargo along a neuron’s fibers to the end of the axon. This transmission of signals, called neurotransmission, is essential to normal brain function. Reactive oxygen species, which are naturally released during the metabolism of oxygen, can cause damage to the brain. In healthy brains, there are important mechanisms at work to keep the amounts of reactive oxygen species in check. The brain also has a glymphatic system, which is responsible for removing waste and debris that build up in the brain.

In addition to the glymphatic system, there are other mechanisms in place to keep the brain healthy. One of these is called neuroplasticity, which is the brain’s ability to change and adapt over time. Neuroplasticity allows the brain to form new neural connections and pathways, which is essential for learning and memory.

Another mechanism is neurogenesis, which is the production of new neurons in the brain. It was once believed that humans were born with a fixed number of neurons, and that no new neurons could be produced throughout life. However, research has shown that neurogenesis does occur in certain parts of the brain, such as the hippocampus, and that it can be influenced by factors such as exercise and diet.

When a traumatic brain injury occurs, these natural mechanisms can be disrupted. For example, the glymphatic system may not be able to remove waste and debris as efficiently, which can lead to inflammation and damage. Neuroplasticity and neurogenesis may also be impacted, making it more difficult for the brain to adapt and recover.

Understanding the basics of how the brain works can help us better understand the impact of a traumatic brain injury and how we can support the healing process.