The Brain – the basics
If you have suffered a traumatic brain injury you may have injured a specific part/s of your brain. To better understand how your brain injury may affect you or your loved one, it can be helpful to look at the different parts of the brain and how they work together. This may help inform any questions you may have for your doctor or healthcare team.
The Cerebrum makes up most of the brain, accounting for around 85% of the brain mass. The Cerebrum is made up of two halves, called the right and left hemispheres, which are connected by a structure known as the corpus callosum. The brain hemispheres are broadly divided into four lobes, each of which have unique functions.
These lobes are:
The Frontal Lobe – as the name suggests, the frontal lobes are the front part of the brain. They are responsible for executive functions, which include abilities such as reasoning, planning, problem-solving, and regulating emotions.
The Temporal Lobe – the temporal lobes are located on the left and right side of the brain. They play an important role in the processing of sensory information, especially auditory information (i.e. hearing), so that we can respond appropriately to the world around us. In addition to this, the temporal lobes contain brain structures that play important roles in language comprehension and production (Wernicke’s area), learning and memory (hippocampus), object and facial recognition (fusiform gyrus), as well as emotional reactions and processing (amygdala).
The Parietal Lobe – the parietal lobes make up the top rear part of the brain. They are responsible for processing some sensory information, including touch, temperature and pressure. The parietal lobes are also responsible for sensory integration, learned movements, and location awareness.the parietal lobes make up the top rear part of the brain. They are responsible for processing some sensory information, including touch, temperature and pressure. The parietal lobes are also responsible for sensory integration, learned movements, and location awareness.
The Occipital Lobe – located towards the back of the brain, the occipital lobe is the major visual processing area in the brain. It receives information from both eyes, which it interprets into things including distance, identity, and location.
The Cerebellum (Latin for “Little Brain”) is the second largest part of the brain. Sometimes called the fifth lobe of the brain, the cerebellum is located beneath the cerebrum, towards the back of the brain. It is responsible for functions relating to posture, balance and coordination, which include coordinating movement through a number of muscle groups, coordinating eye movement, and gross and fine motor skills.
The Diencephalon is the third largest section of the brain. Located at the core of the brain, the diencephalon is the size of a plum and has two major parts – the thalamus and the hypothalamus.
The thalamus receives sensory information from all over the body which it then sends to specific areas of the cortex for further processing.
The hypothalamus lies just below the thalamus and makes up roughly 1% of the brain mass. The hypothalamus has a number of functions, though its main function is to ensure the body is stable (i.e. maintaining homestasis). The hypothalamus also responds to stress and controls the secretion of melatonin, cortisol and body temperature over a 24-hour period.
The Brain Stem
The brain stem is located at the base of the diencephalon and is made up of 3 structures called the midbrain, pons and medulla. The brain stem controls many of the body’s automatic functions that are essential for life, such as breathing, swallowing, heart rate and regulating blood pressure and sleep. It also plays a role in balance, coordination, and reflexes.
The Blood-Brain Barrier
The blood-brain barrier is a protective barrier around the brain. This highly intelligent barrier stops bad stuff (like toxins) from getting into the brain all while allowing the good stuff (such as oxygen) to enter.
Learn more about what happens during a mild traumatic brain injury with article ‘What is a mild TBI or concussion?‘.
References and Further Reading
Updated: July 2023