Brain Anatomy | Basic Facts

Brain Anatomy | Basic Facts

Here are 10 key facts about brain anatomy.

1. What the Brain Is and How It Develops

The human brain weighs roughly 1.3–1.5 kilograms — only about 2% of body weight, yet it demands around 20% of the body’s oxygen-rich blood.

Although most brain growth occurs in childhood, certain higher-level regions — especially the prefrontal cortex, responsible for planning, decision-making, and impulse control — continue to mature until the mid-twenties.

2. The Cerebrum: The Brain’s Largest Region

The cerebrum makes up around 85% of the total brain volume.

It is responsible for:

• Thinking and reasoning
• Memory formation
• Voluntary movement
• Problem-solving
• Language and conscious perception

Its outer layer, the cerebral cortex, is the part most associated with ‘higher thinking.’

3. Two Hemispheres Working Together

The brain is divided into right and left hemispheres. These halves communicate constantly through a thick bundle of nerve fibres called the corpus callosum.
This structure ensures both sides of the brain work in synchrony—for example, combining language (usually left-leaning) with emotional tone (more right-leaning).

4. The Four Lobes of the Brain

Each hemisphere contains four distinct lobes, each controlling specialised functions:

• Frontal lobe: Executive functions, movement, personality, behaviour
• Parietal lobe: Sensory processing, touch, spatial awareness
• Occipital lobe: Vision and visual interpretation
• Temporal lobe: Hearing, memory, language comprehension, musical rhythm

(Detailed breakdown provided further below.)

5. The Cerebellum: Master of Balance and Coordination

Sitting beneath the cerebrum, the cerebellum fine-tunes movement.
It ensures:

• Smooth, coordinated actions
• Good balance
• Accurate, fine motor control (e.g. writing, buttoning a shirt)

Damage here often leads to unsteady walking and clumsy movements.

6. The Brainstem: The Body’s Life Support Centre

The brainstem connects the brain to the spinal cord and consists of the midbrain, pons, and medulla.
It controls essential involuntary functions such as:

• Respiratory rate (RR)
• Heart rate (HR)
• Blood pressure (BP)
• Swallowing
• Sleep–wake cycles

Many cranial nerves originate here.

7. The Thalamus: The Brain’s Relay Hub

Situated deep in the brain, the thalamus acts as a major relay station.

It receives sensory information (except smell) and directs it to the correct areas of the cortex for interpretation.

8. The Hypothalamus: The Body’s Internal Regulator

The hypothalamus, found just below the thalamus, plays a critical role in maintaining internal balance. It:

• Regulates body temperature
• Controls hunger and thirst
• Coordinates sleep rhythms
• Influences emotions
• Sends signals to the pituitary gland, controlling hormones throughout the body

9. Blood Supply: How the Brain Receives Oxygen

The brain is fed by two major arterial systems:

Carotid arteries

• Travel up the sides of the neck
• Internal carotids supply the front and upper regions of the brain
• External carotids supply the face and scalp

Vertebral arteries

• Travel along the spinal column
• Join to form the basilar artery
• Supply the brainstem, cerebellum, and back of the brain

Without constant blood flow, brain cells begin to die within minutes.

10. The Meninges: The Brain’s Protective Layers

The brain is wrapped in three protective membranes called the meninges:

• Dura mater – tough, outer layer

• Arachnoid mater – web-like middle layer

• Pia mater – delicate inner layer closely attached to the brain surface

Between these layers is cerebrospinal fluid (CSF), which cushions the brain and acts as a shock absorber.

More Fascinating Brain Facts

• About 60% of the brain is fat, making it the fattest organ in the body.
• It contains roughly 86 billion neurons, each capable of forming thousands of connections—potentially reaching a quadrillion synapses.
• The brain cannot feel pain because it lacks pain receptors (though it interprets pain from elsewhere).
• Around one-quarter of the body’s cholesterol is found in the brain, necessary for nerve insulation and communication.
• Elephants have exceptionally large brain areas dedicated to controlling their trunks.
• Zebrafish can regenerate their spinal cord, offering hope for future treatments for paralysis.

Detailed Guide to the Four Brain Lobes

Frontal Lobe

• Governs planning, judgement, personality, decision-making, and voluntary movement
• Includes Broca’s area, essential for speech production
• Also contributes to smell recognition

Parietal Lobe

• Processes touch, temperature, and pain
• Helps recognise objects and understand spatial relationships
• Contains Wernicke’s area, which allows comprehension of spoken language

Occipital Lobe

• Responsible for vision
• Interprets colour, movement, and visual patterns

Temporal Lobe

• Plays a major role in memory formation
• Involved in hearing, language, and rhythm perception
• Helps identify smells and recognise soundsgnition.