The brain is an amazing part of our body. It’s in charge of our thinking, memory, emotions, and many other things. It works with the spinal cord to control how we move, see, breathe, and feel.1

The average adult brain weighs around 3 pounds. Surprisingly, it’s made up of 60% fat. The rest is mostly water, protein, and other materials.1

This organ is not a muscle, but it houses different parts like blood vessels and nerves. Among these are neurons and glial cells. The brain is split into the cerebrum, brainstem, and cerebellum. Each part has its own job and features.

Key Takeaways

  • The brain is a complex organ that controls a wide range of functions in the human body.
  • The brain is composed of three main parts: the cerebrum, brainstem, and cerebellum.
  • The brain weighs approximately 3 pounds and is made up of 60% fat and 40% water, protein, carbohydrates, and salts.
  • The cerebral cortex, which covers the cerebrum, makes up about half of the brain’s weight.
  • The brain is divided into four lobes: frontal, parietal, temporal, and occipital, each with specialized functions.

Brain Anatomy: An Overview

The cerebrum is the brain’s biggest part. It has the cerebral cortex (gray matter) and white matter under it.1 The cerebral cortex is wrinkly. It’s split into two hemispheres joined by the corpus callosum. This structure helps the hemispheres talk to each other.2 There are four types of lobes within these hemispheres. They are frontal, parietal, temporal, and occipital. Each one does different jobs.

Cerebrum: The Largest Part of the Brain

The cerebrum is key and big. It makes up almost half the brain’s weight.1 It handles our thinking, what we feel, and moves our bodies.

Cerebral Cortex: The Brain’s Gray Matter

The cerebral cortex is the cerebrum’s outer layer. It’s made of gray matter.1 This part is crucial for understanding, thinking, and moving as we choose.

Hemispheres and the Corpus Callosum

The brain has two hemispheres, left and right. They are linked by the corpus callosum.2 This link helps the hemispheres work together. So, we can do things smoothly and well.

The Brain’s Lobes and Their Functions

The brain has four main lobes – frontal, parietal, temporal, and occipital. Each lobe is vital for different tasks like thinking, feeling, and moving.3 These lobes are part of the cerebral cortex which has two sides connected by the corpus callosum.3

The frontal lobe helps with managing emotions, making plans, and solving problems.3 It also controls our movements through the primary motor cortex.3 Illnesses like frontotemporal dementia show personality changes early on, showing how important this lobe is for how we behave and think.3

The parietal lobe takes care of information from our senses like touch, temperature, and pain.3 It helps us tell where our body is touched and lets us feel different touches.3

The temporal lobe is key for hearing and understanding sounds, speech, and language.3 It also deals with some vision like recognizing faces, as well as emotional memories.3

The occipital lobe is all about seeing and identifying what’s around us.3 It receives and processes information from the eyes to tell us about the world visually.3

These lobes work together for everything from what we sense to how we think and move.4 The brain has many nerve cells that talk to each other using chemicals.4

Frontal Lobe: Executive Functions and Movement

The frontal lobe is key for thinking and moving. It’s in charge of big thoughts, like planning and problem-solving, and feelings.3 It’s also where our brain decides to move our muscles.3 This lobe covers a big part of our brain and plays a major role in how we think and feel.5 Since it’s at the front, it can easily get hurt, which might affect how we behave.6

Higher Cognitive Functions

The front lobe’s front part, the prefrontal cortex, has different parts for thinking and acting.5 They help us make decisions and control impulses. When this part gets hurt, we might act differently, with weird feelings or poor decisions.6

Primary Motor Cortex

The back part of the frontal lobe is for moving our body as we want.5 It gets help from other brain parts to plan and do complex moves. Hurt in this area can mean we have trouble moving part of our body.5

The Remarkable Case of Phineas Gage

Phineas Gage’s story highlights how the frontal lobe impacts who we are and how we act.3 After his accident, he changed a lot. It showed how crucial this part of the brain is for our personality and actions.3

Parietal Lobe: Sensory Integration

The parietal lobe manages sensory information. This includes touch, temperature, pressure, and pain.3 It helps us feel different types of touch. For example, we can tell if two points on our skin are not touching. This is called two-point discrimination.3 Sensitivity varies by body part. You can test this with tools such as a folded paperclip.

Processing Touch, Temperature, and Pain

The parietal lobe is vital for touch, taste, and temperature.7 If it’s damaged, people might lose their sense of touch. Or they might have trouble processing what they feel.7 Specific parts of the lobe include the somatosensory cortex. And the superior parietal lobule as well as other parts.7

Two-Point Discrimination

Two-point discrimination tests how well the parietal lobe works.3 This method lets us find out how well someone can tell two points on their skin apart. The parietal lobe is split into two sides, each with different areas.8 It handles input about how things feel. The more sensory input an area gets, the more brain space it needs to process that info.8

parietal lobe

The parietal lobe is vital for knowing your surroundings. It helps with taste, hearing, sight, touch, and smell.8 It also plays a key role in understanding where you are. And in recognizing numbers, shapes, and sizes. Plus, it helps you move your hands and eyes together.8 This lobe works closely with the occipital lobe. Together, they help you see, understand space, and solve problems.8

Temporal Lobe: Hearing, Language, and Memory

The temporal lobe is key for processing what we hear and see. It helps us make sense of speech, understand languages, and spot different sounds.3 Besides, it tackles detailed visual data, like faces and places.3 This lobe, one of the brain’s main parts,9 deals with hearing, knowing languages, and making memories.3

Auditory Processing

The primary auditory cortex lives in the temporal lobe. It manages what we hear and lets us grasp speech, languages, and different sound types.3 But, problems in this lobe can cause trouble speaking, like in Wernicke’s aphasia after a stroke in that area.9

Visual Processing of Faces and Scenes

Special parts of the temporal lobe also help understand complex visuals, including faces and scenery.3 They team up with the main visual cortex to make sense of what we’re seeing.

The Role of the Hippocampus

In the medial temporal lobe, the hippocampus is vital for memories, learning, and feeling emotions.3 It turns short-term moments into long-term memories and guides us in space.3 But, damage to the hippocampus might cause memory problems, like not being able to learn well or remember new things.9

Occipital Lobe: The Visual Cortex

The occipital lobe is the main area in the brain for seeing.10 It is the smallest of the four lobes. There’s one on each side of your brain.10 It helps us make sense of what our eyes see.10

Primary Visual Cortex (V1)

V1 takes in and works on what we see.10 It does a lot for our vision. For example, it figures out distance, color, and face recognition.10 It has key parts like V1, V2, and other sections.10

Secondary Visual Processing Areas

V1 passes the processed visuals to other areas for a deeper look.11 Problems with the occipital lobe can be from different causes. These include brain injuries or infections.11 Symptoms might be not seeing well or seeing things that aren’t there.11

This lobe is very important for our sight. Knowing how it works help us treat vision problems.10 Issues with it can cause some big troubles. For example, it might make it hard to see colors or faces.10

It connects with other brain parts and with the eyes.10 Knowing about it helps doctors fix eye and brain problems.12

It’s connected to the eyes and works closely with the temporal lobe.10

Key Features of the Occipital LobeDetails
Size and LocationThe occipital lobe is small and at the back of the brain.12
AnatomyIt has three unique parts on its outer area.12
FunctionsIt’s key for vision, seeing colors, recognizing objects, and remembering faces.12
Blood SupplyIt gets blood from the back of the brain.12
Clinical SignificanceSurgery on it can help with some brain problems. Finding and treating seizures in this area can be tough.12

The occipital lobe handles a lot of our vision tasks. V1 starts, and other areas dive deeper into what we see. Problems here may affect how we see and understand the world.111012

The Brain’s Lobes: Understanding Their Functions

The brain has four main lobes: frontal, parietal, temporal, and occipital. Each lobe does different jobs for thinking, feeling, moving, and sensing. The biggest part, the cerebrum, controls our high-level thinking, feelings, and actions. Below that, the cerebellum helps us move and stay balanced. And the brainstem looks after very important tasks like our heart, breathing, and reflexes.3

The frontal lobe helps manage our emotions, plan, solve problems, and move freely. When the frontal lobe is hurt, like in frontotemporal dementia, people might show big changes in their personality first.3 The parietal lobe takes care of our feelings like touch, heat, pressure, and pain. It lets us tell where things are when we touch them, known as two-point discrimination.3

The temporal lobe is key for hearing, understanding speech, making memories, and dealing with what we see and hear. Inside it, the hippocampus is vital for remembering, learning, and feeling.3 Lastly, the occipital lobe is all about seeing. It’s where the brain works on what our eyes see.3

When the brain folds, it makes bumps and dips, or gyri and sulci. This folding increases the brain’s surface, fitting more in our heads. More than half of our brain is fat. And half of the brain’s weight is the cortex, split into two sides.1

Cerebellum: Coordination and Balance

The cerebellum, often called the “little brain,” sits at the bottom back of your skull. It’s beneath the temporal and occipital lobes. Its main job is steering voluntary muscle moves and keeping you upright.13 More than half of all brain nerve cells are here, even though it weighs just 6 ounces.13 The vermis, a part in the middle, joins the two hemispheres. Overall, the cerebellum wraps around the brain stem in a half-circle shape.13

Voluntary Movement and Posture

The cerebellum is key in making our moves precise and well-coordinated. It cooperates with the motor cortex to not only move us but balance us. This keeps our bodies steady up straight.14 Even though it’s small, making up just 10% of the brain, it holds about 80% of all the brain’s nerve cells.14

Emerging Roles in Cognition and Behavior

New studies show the cerebellum might do more than coordinate our moves. It could help with thinking, feeling, and how we act around others.13 Problems in the cerebellum might lead to issues like autism, anxiety, or not reading well.13 Most cases of Friedreich’s ataxia, a type of genetic condition, are rare, affecting just a few in 40,000 people.14 Strokes are not common in the cerebellum either, only making up about 1-4% of all strokes.14 Sporadic ataxia, which is not inherited, usually moves slowly and can turn into a more severe condition. Exercising at least 2.5 hours per week can lower stroke risk and keep your heart healthy.14


Brainstem: Vital Functions and Reflexes

The brainstem links the brain and spinal cord. It includes the midbrain, pons, and medulla.15 This area is crucial for keeping us alive by controlling important functions and reflexes.

Midbrain: Movement and Environmental Responses

The midbrain helps with moving our eyes and reacting to what we see and hear.15 It has important structures for these tasks. For example, the corpora quadrigemina help process vision and sound.

The trochlear nerve, which controls eye movement, comes from the midbrain. This shows how important the midbrain is for managing what we see.15

Pons: Cranial Nerve Origins and Functions

The pons connects the medulla and midbrain.15 It’s a key area for basic functions. For example, it’s important for waking up and being alert.

Many cranial nerves start in the pons. They help with activities like feeling in your face and keeping balanced.15

Medulla: Regulating Breathing, Heart Rate, and Reflexes

The medulla handles crucial body functions, from breathing to heart rate.15 It also controls reflexes like gagging and sneezing. So, it’s really important for keeping us going.

Components like the pyramids and olivary bodies are in the medulla. It is where nerves for swallowing and other vital tasks come from.15 This shows how essential it is for our basic health needs.

The reticular formation and corticospinal tracts in the brainstem help with lots of important things.15 These include moving, being alert, and controlling our body without thinking about it. They are central to our wellbeing.

Overall, the midbrain, pons, and medulla work together for our most basic needs.15 They are key for living a healthy life.

Deeper Brain Structures and Their Roles

In the brain, many deep structures are vital for us. They work hard to keep our bodies and minds in good shape. Even though they sit under the cerebral cortex, they affect our health in big ways.

Pituitary Gland: The Master Gland

The pituitary gland is tiny and found at the base of the brain, just behind the nose. It’s called the “master gland” because it controls other glands. For example, it tells the thyroid to help with growth and the adrenals to handle our stress.1

Hypothalamus: Regulating Temperature, Sleep, and Hunger

The hypothalamus sits at the brain’s base and is crucial for keeping us in balance. It takes care of body temperature, the sleep cycle, and our food and drink needs.16 It does this by telling the pituitary when it needs to act.

Amygdala: Emotions, Memory, and the Fight-or-Flight Response

The amygdala looks like an almond and is in charge of our emotional life. It helps us remember things and decides when to fight or run away.16 This part of the brain is key for spotting danger, remembering how it made us feel, and reacting fast when needed.

Learning about these deep brain parts helps us understand how our health is managed. Each part, from the pituitary to the amygdala, does its bit to keep us strong and healthy. From controlling our stress actions to processing emotions, they all matter.

Brain Coverings and Cerebrospinal Fluid

Three layers of membranes, the meninges, wrap the brain and spinal cord. These are the dura mater, arachnoid mater, and pia mater.1 They shield our delicate nervous system and let cerebrospinal fluid (CSF) flow. CSF is key as it acts like a cushion and brings food to our nerve cells.1

Meninges: Protective Layers

The dura mater is on the outside and is tough. It guards the brain and spinal cord. Inside it, the arachnoid mater forms a delicate, web-like sheet. The innermost layer, the pia mater, closely wraps around the brain and spine. This grouping gives a solid defense to our neural system.1

Cerebrospinal Fluid: Cushioning and Nutrient Delivery

Special centers inside the brain make cerebrospinal fluid (CSF).1 It moves around the brain and spine, taking out trash and adding nutrients.17 CSF acts like a soft pillow, keeping our nervous system clean and fed.1

Blood Supply to the Brain

The brain always needs blood and oxygen to work right. Two sets of blood vessels provide this: the carotid arteries and the vertebral arteries. The carotid arteries send blood to the front of the brain.18 And, the vertebrae arteries carry blood to the back of the brain.18

The carotid arteries’ branches form the anterior and middle cerebral arteries. These arteries supply the forebrain, deep brain areas, and the cortex.18 The vertebrae arteries merge to create the basilar artery. It pairs with the carotid arteries at the circle of Willis near the brain’s base.18

The posterior cerebral, basilar, and vertebrae arteries make up the back flow to the brain. They support the midbrain, back of the cortex, and the brain’s stem.18 A block in blood flow can harm the brain, causing injury, and even strokes.18 There are new ways to check blood flow in the brain without cutting it open. These ways are better than old methods like doing autopsies.18

Source Links

  5. Lobe.EF.pdf

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