Our understanding of the human brain has come a long way since scientists first started studying this intricate organ. Throughout history, the brain has been thought to have different purposes and varying levels of importance, with some thinking that it was not really important at all. But steadily, researchers grew to understand more about what makes this important, complex organ run efficiently.  

Surprisingly, the brain uses a disproportionally large portion of our blood supply compared to its size—consuming approximately 20% of what your heart pumps out. It also uses a large percentage of our oxygen supply. The brain receives blood through thousands of miles of blood vessels that cover and run through its different regions. This network of vessels gives your brain the oxygen and nutrients it needs to maintain the function of the diverse cell populations that work together to continuously perform—and make it possible for you to read this paragraph.  

To better understand how the brain works, let’s focus on the two most abundant cell types in the brain and the important roles they both play.  

Neurons 

Neurons are cells found within the brain and the spinal cord, where billions of neurons are constantly sending and receiving signals. These cells work together through different branch-like arms, known as dendrites (think of a branch) and axons (think of a tree trunk). 

Neurons can take on a range of sizes and shapes depending on their specific function, but they all use chemical or electrical signals to communicate with one another and to the rest of your body to keep it running consistently and efficiently. 

When neurons are injured or damaged, the signals they send can become interrupted. Depending on where in the brain the injured neurons are located, this can lead to changes in muscle function, memory or speech.  

Glial cells 

Glial cells provide support to the neurons in the brain by helping them deliver signals, cleaning debris from the brain and responding to injury. Although the glial cells’ job is to respond to injury, if they are active in this role for too long, neuroinflammation can result. Glial cells are thought to play a part in many neurological conditions, including Alzheimer’s and Parkinson’s diseases.  

While scientists have come a long way in understanding the human brain, there is still a lot yet to uncover. Understanding the different types of neurons and glial cells—as well as other cell types in the brain—and how they interact in the brain in aging, injury and disease can lead to better treatments and therapies for the millions of people with neurological disorders, from migraines to Alzheimer’s disease to traumatic brain injury.