Main Parts of the Brain: Structures and Their Functions

The brain is one of the most fascinating organs in the human body. The 3-pound organ contains billions of neurons and makes up about 2% of your whole body weight.

The human brain is a complex mystery that only it can resolve. The incredible powerhouse controls how your body functions, your emotions, thoughts, speech, memory, creativity, and deciphers and stores information from the outside world.

The brain receives information from your 5 senses organs; eyes, nose, skin, tongue, and ears, takes the data and assembles the messages in a way we can understand.

As we dig deeper into this article, you’ll discover the brain’s anatomy and the function of each structure.

The Main parts of the brain
The main parts of the brain

Main Parts of the Brain: Structures and Their Functions

The brain is made up of 3 essential parts;

The main parts of the brain are composed of multiple structures with distinct functions.

The Forebrain

The forebrain is the largest part of the brain, most of which is the cerebrum. The forebrain controls our body temperature, emotions, thinking, hunger, and reproductive functions.

It includes the cerebrum, hypothalamus, and thalamus.

The Cerebrum

The cerebrum, also known as the cerebral cortex, is the largest and uppermost part of the human brain. In fact, it accounts for 85% of the brain’s weight. The cerebrum includes the 2 cerebral hemispheres and is responsible for your thoughts, actions, and other higher brain functions.

The Two Hemispheres

If you divide the brain into 2 equal parts, you’ll have the 2 cerebral hemispheres. The brain has a rough surface (cerebral cortex) with uneven bumps known as gyri and grooves known as sulci.

The gyri and sulci form important divides that separate the brain into functional centers. The most essential sulcus is the longitudinal fissure, a deep furrow that divides the brain into two equal halves or hemispheres: the left hemisphere and the right hemisphere.

functional areas of the brain
functional areas of the brain

Functions of the hemispheres

Although the hemispheres look identical, the left and right hemispheres have very specific functions. While the left hemisphere (logical side) controls language and speech, the right hemisphere (creative side) is responsible for translating visual information.

The two hemispheres are linked by a bundle of axons known as the corpus callosum.

Pro tip: In extreme cases, certain people who are left-handed process speech on the right side of their brain.

Right HemisphereLeft Hemisphere
 CreativityAnalytical skills/Problem solving
Control muscles of the left side of your bodyControl muscles of the right side of the body
Visual imagery
Spatiotemporal awarenessReasoning

The forebrain is also divided into 4 crucial structures known as lobes.

The lobes of the forebrain include the frontal lobe, the parietal lobe, the occipital lobe, and the temporal lobe.

Functions of the Lobes

Frontal Lobe – The frontal lobe rests just below the forehead and controls our reasoning, organizing, our ability to speak, solve problems, pay attention and our emotions.

Parietal Lobe – The parietal lobe lies at the upper rear of our brain. This lobe manages our complex behaviors, including the 5 senses; touch, vision, and spatial awareness.

The parietal lobe also relays sensory information from different parts of the body, helps us process and learn a language, and maintains the body’s positioning and movement.

Occipital Lobe – The occipital lobe is located at the rear of our brain. This lobe is responsible for our visual awareness, including visual attention, optical recognition, and spatial awareness.

It also controls our ability to interprets body language like facial expressions, gestures, and body postures.

Temporal Lobe – Your temporal lobe sits close to your ears and is associated with interpreting and translating auditory stimuli. For example, your temporal lobe allows you to focus on one voice in a loud party.

This lobe also helps you understand oral language, general process knowledge, and stores your verbal and visual memory.

The Midbrain

The midbrain sits just below the cerebrum and above the hindbrain. It is located right at the center of your brain.

The midbrain includes the cerebral aqueduct, cerebral peduncles, tectum, tegmentum, the fasciculi, and several nuclei.

Compared to the forebrain and hindbrain, the midbrain is relatively small.

Despite its small size, it plays an essential role in processing visual and auditory stimuli.

The midbrain also contains small portions of the red nucleus and substantia nigra. These 2 structures help to control motor movements, particularly eye movements.

The substantia nigra also produces a large amount of dopamine-producing neurons.

Pro-tip: When the neurons in the substantia nigra degenerate, the brain becomes prone to Parkinson’s disease.

Limbic System – The limbic system is a complex brain structure that lies deep in the cerebrum. It contains the thalamus, hypothalamus, hippocampus, and amygdala.

Since it plays a significant role in controlling our emotions and forming our memories, it is often called our “emotional brain” or ‘childish brain.’

Thalamus – The thalamus is a small mass of grey matter that relays sensory information from the spinal cord, brainstem, and other parts of the brain to the cerebral cortex.

The thalamus is also responsible for the regulation of alertness and our consciousness.

Hypothalamus – The hypothalamus is a part of the brain that sits right below the thalamus.

Although the hypothalamus is a tiny part of the brain, it has one of the most crucial and busiest roles.

The primary function of the hypothalamus is maintaining homeostasis in the body.

It’s also responsible for releasing hormones, regulating body temperature, controlling appetite, and managing sexual behavior.

Amygdala – The amygdala is a small, almond-shaped structure in the limbic system that processes strong emotions like fear, aggression, and anxiety.

The amygdala is located close to the hippocampus. It contains a large number of receptor sites that can also perceive certain emotions and the storing and retrieving of emotional memories.

Hippocampus – The principal role of the hippocampus is forming, organizing, and storing short and long term memories.

The hippocampus also helps form new memories and link emotions, feelings, and sensations such as specific smell and sound to these memories.

 Pituitary Gland – The pituitary gland is a small, pea-shaped gland located at the brain’s base, just behind the bridge of the nose. The pituitary gland produces different hormones that regulate many of the body’s processes, including growth, sexual development, metabolism, and reproduction.


The hindbrain is the third major part of the brain. Like its name, the hindbrain is located at the extreme end of your brain. It includes the cerebellum, pons, medulla, and most of the brain stem.

Cerebellum – The cerebellum is often referred to as our little brain. Just like the cerebrum, the cerebellum has two equal hemispheres and a wrinkly surface.

The cerebellum is responsible for coordinating most of our voluntary movements like posture, balance, and even speech.

Brain Stem – The brain stem is the posterior part of the brain that connects the brain with the spinal cord. The brain stem comprises parts of the midbrain, pons, and medulla, all of which have specific functions.

Each part of the brain stem works together to regulate essential life functions, including body temperature, breathing, heartbeat and blood pressure.

Pons – The pons is the largest structure in the brain stem and is found above the medulla and underneath the midbrain, and in front of the cerebellum.

The pons functions as a bridge between several parts in the nervous system, including the cerebrum and cerebellum.

The pons also contains many vital nerves such as;

The trigeminal nerve – This nerve controls facial muscles that are involved in chewing, biting, and swallowing.

The abducens nerve – The abducens nerve allows the eyes to look from side to side.

The vestibulocochlear nerve – This nerve controls hearing and balance.

The pons also helps regulate sleep cycles, breathing patterns, respiration, and reflexes.

Medulla – The medulla is a cone-shaped structure located in front of the cerebellum. The prominent role of the medulla oblongata is regulating involuntary (autonomic) functions, including breathing, digestion, sneezing, swallowing, and heart rate.


The skull is a fusion of bones that protects the brain, the brainstem, and outlines the face.

The 8 bones that protect your bones from injury include:

  • 1 frontal bone
  • 2 parietal bones
  • 1 occipital bone
  • 2 temporal bones
  • 1 sphenoid bone
  • 1 Ethmoid bone
brain functions
                                                                             brain functions

Brain Conditions

Your brain is one of the most complex organs in the human, and if one of the brains structure is damaged, it could lead to a brain condition.

For example, if your Broca’s area is damaged, you may have trouble moving your tongue, and your speech may be slow and poorly articulated.

Other conditions that could affect the brain include;

Brain aneurysm: When an artery in the brain swells, it could lead to a brain aneurysm. If the aneurysm ruptures, it could cause a stroke.

Brain tumor: When any tissue in your brain starts growing abnormally, it could be symptoms of benign or malignant cancer.

Intracerebral hemorrhage: Bleeding inside the brain can cause difficulty speaking or difficulty walking.

Concussion: When there’s a heavy blow to the head, you may experience a concussion and temporarily lose brain function.

Cerebral edema: Electrolyte imbalance in the brain could lead to swelling of the brain tissue.

Glioblastoma: Glioblastoma is a brain tumor that develops very rapidly and creates pressure on the brain.

Pro tip: Glioblastoma is usually aggressive and could be very difficult to cure.

Meningitis: When the lining around the brain or spinal cord becomes inflamed from an infection, you may have meningitis. Other symptoms associated with meningitis include; headache, fever, sleepiness, neck pain, and stiff neck.

Encephalitis: Encephalitis usually arises when tissue in the brain becomes inflamed. It’s usually a result of a viral infection and could cause fever, headache, and confusion.

Traumatic brain injury: A severe head injury could lead to permanent brain damage. Other symptoms include mental impairment and personality, and mood changes.

Parkinson’s disease: Degeneration of nerves in the brain could lead to the development of Parkinson’s disease. People with Parkinson’s disease may experience hand tremors and problems with their coordination and movement.

Epilepsy: Although there’s no exact cause for epilepsy, head injuries and several strokes can trigger epilepsy. People with epilepsy may also experience seizures.

Dementia: When a nerve cell in the brain starts malfunctioning or degenerating slowly, it could lead to dementia. Strokes and alcohol abuse could also cause brain dementia.

Alzheimer’s disease: Alzheimer’s disease is known as senile dementia. Here, the nerves in the brain degenerate, causing progressive dementia.

Brain abscess: A brain abscess occurs when there’s a pocket of infection in the brain. Brain abscesses are usually caused by bacteria and may require either antibiotics or surgical removal.

Maintaining a healthy brain

As we age, certain areas of the brain start to shrink, especially areas that are important to learning and storing memories.

The good news is – You can follow some tips to keep your brain in excellent health and slow down mental decline.

Here are some tips you can use to maintain a healthy brain.

  1. Do mental exercises

Doing mental exercises like doing crossword puzzles, reading regularly, or learning a new language helps improve your mental fitness. Doing mental exercises stimulate nerve cells and may even trigger the development of new brain cells.

  1. Protect your head

Injuries to the head can cause brain concussions, other severe brain injuries. You can protect your head by wearing helmets or other protective gear when you’re playing contact sports.

  1. Physical exercise

Doing regular physical exercises doesn’t only help your muscles; it helps your brain too. Exercising improves blood flow in your body, including your brain.

Moderate exercise also lowers blood pressure, reduces mental stress, and could trigger the development of new nerve cells.

  1. Quit smoking and excessive Alcohol

Smoking isn’t only bad for your general health; it could also lead to cognitive decline in the brain.


The brain is an incredibly complex powerhouse. The extraordinary 3-pound organ contains about 100 billion interconnected nerve cells and glia.

Although each structure has a distinct function, they work together to control all functions of the body.

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