Brain Structure and Hemispheres

Your brain has three main parts that work together like a perfectly coordinated team. The cerebrum is the largest section and handles all your "thinking" activities like problem-solving, emotions, and interpreting what you see and hear. The cerebellum sits underneath and keeps you balanced whilst coordinating your movements. The brainstem connects everything to your spinal cord and runs your body's autopilot functions like breathing and heart rate.

The cerebrum splits into two halves called hemispheres, connected by a bridge of fibres called the corpus callosum. Here's something fascinating: each hemisphere controls the opposite side of your body. So if someone has a stroke on the right side of their brain, their left arm might become weak.

The left hemisphere typically handles speech, writing, and logical thinking, whilst the right side manages creativity, spatial skills, and artistic abilities. About 92% of people are left-hemisphere dominant for language and hand use.

Quick Fact: If you're right-handed, your left hemisphere is likely controlling your dominant hand and language skills!

Brain Lobes and Their Functions

Your cerebrum is divided into four distinct lobes, each with specialised jobs that work together seamlessly. Think of them as different departments in a company, each handling specific tasks but constantly communicating with each other.

The frontal lobe is your brain's CEO, managing personality, decision-making, and planning. It contains Broca's area for speech production and the motor strip that controls body movement. The parietal lobe processes touch, temperature, and pain through its sensory strip, whilst also helping you understand spatial relationships.

Your occipital lobe at the back interprets everything visual - colours, light, and movement. The temporal lobe on the sides handles hearing, memory formation, and contains Wernicke's area for understanding language.

These lobes don't work in isolation. When you're reading this summary, your occipital lobe processes the visual text, your temporal lobe helps with comprehension, and your frontal lobe focuses your attention.

Study Tip: Remember the lobes by their locations - frontal (front), parietal (top), occipital (back), temporal $sides/temples$.

Language Processing and Brain Structure

Language processing showcases how specialised your brain really is. The left hemisphere typically dominates language functions, earning it the title "dominant hemisphere." However, about one-third of left-handed people might have their speech centre on the right side instead.

When language processing goes wrong due to brain injury, it causes aphasia. Broca's aphasia occurs when the frontal lobe's speech area is damaged - people understand perfectly but struggle to form words. Wernicke's aphasia affects the temporal lobe's language area, causing people to speak in long, meaningless sentences without realising their mistakes.

Your brain's surface, called the cortex, appears folded like a crumpled piece of paper. These folds called gyri (hills) and sulci (valleys) dramatically increase surface area, allowing 16 billion neurons to fit inside your skull. The grey matter contains cell bodies, whilst white matter beneath consists of connecting fibres.

This folding is crucial for higher-level thinking. Without these folds, your skull would need to be enormous to contain the same processing power.

Memory Aid: Broca = Broken speech (can't speak well), Wernicke = Wordy nonsense (speaks but makes no sense).

Deep Brain Structures

Beneath your cortex lie crucial structures that control basic survival functions and complex behaviours. The hypothalamus acts as your body's thermostat and master controller, regulating hunger, thirst, sleep, body temperature, and hormone release.

The pituitary gland, known as the "master gland," sits in a bony pocket and controls other hormone-producing glands throughout your body. The pineal gland helps regulate your sleep-wake cycle by secreting melatonin. The thalamus serves as a relay station, filtering and directing information to appropriate brain areas.

Your basal ganglia work with the cerebellum to fine-tune movements, whilst the limbic system processes emotions, learning, and memory. The limbic system includes the amygdala for emotional reactions and the hippocampus for memory formation.

These deep structures demonstrate how your brain operates on multiple levels simultaneously, managing both conscious thoughts and unconscious bodily functions.

Think About It: Your hypothalamus is smaller than an almond but controls vital functions that keep you alive every second!

Memory Formation and Types

Memory isn't just one process but three distinct phases: encoding (deciding what's important), storing, and recalling. Different brain areas specialise in different types of memory, working together like a sophisticated filing system.

Short-term memory operates in your prefrontal cortex, holding about seven items for roughly one minute. This is what you use when someone tells you a phone number and you need to remember it long enough to dial. Long-term memory gets processed in the hippocampus and has virtually unlimited capacity - it stores everything from your childhood memories to facts you learned in school.

Skill memory lives in your cerebellum and basal ganglia, storing automatic learned behaviours like riding a bike or typing on a keyboard. Once these skills are encoded, you can perform them without conscious thought.

The key to moving information from short-term to long-term memory is attention and rehearsal. Your brain literally has to decide what's worth keeping permanently.

Study Strategy: Understanding these memory types can help you develop better learning techniques - use repetition for facts and practice for skills!

Brain Protection Systems

Your brain floats in a protective bath of cerebrospinal fluid (CSF), produced by ribbon-like structures called the choroid plexus inside hollow spaces called ventricles. This clear, colourless fluid acts like a shock absorber, cushioning your brain from injury during everyday activities.

The CSF continuously circulates through four connected ventricles and around your brain and spinal cord before being absorbed and replenished. This system maintains proper pressure and removes waste products from brain tissue.

Think of it like your brain having its own personal swimming pool that provides protection, nutrition, and waste removal all in one elegant system.

Amazing Fact: Your brain produces about 500ml of CSF daily, replacing it completely every 6-8 hours!