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The Brain

BrainThe brain is a highly complex structure that controls how you function and interact with your surroundings. The brain and spinal cord make up the central nervous system. (Read about "The Nervous System") The major portions of the brain, according to the National Institutes of Health (NIH) are:

At the lowest part of the brain, where the spinal cord connects, is what is called the brain stem. It is made up of the medulla and the pons. The brain stem is what controls those things we don't think about, things like our heartbeat and our breathing. It also plays a role in telling us when we are hungry and when it is time to sleep.

Located above and behind the brain stem, in the lower part of our skull, is the cerebellum. The cerebellum is responsible for voluntary muscle movements. It helps us keep our balance, walk and do any number of motor tasks.

Above the brain stem is what is called the limbic system. The main parts are the amygdala and the hippocampus. NIH says they are part of the early evolution of our brains. They are involved in basic emotions, especially ones that help us survive, like fear and anger. They are also involved in pleasure sensations. The amygdala and the hippocampus are also involved in the formation of memories.

Right near the limbic system is the diencephalon. The major parts here are the thalamus and the hypothalamus. The thalamus acts as an exchange point for the thinking part of the brain and the sensory signals from the rest of the body. It also works with the cerebellum to keep us standing. The hypothalamus plays a role in regulating hormones and other chemicals that affect many things, including our heart, blood pressure, breathing, even whether we blush or not. It has a direct affect on the pituitary gland. The hypothalamus and the pituitary gland are part of our endocrine system. (Read about "Endocrine System")

The largest part of the brain is the cerebrum, which lies over all the rest of the portions of the brain. The cerebrum is made up of two halves called the left and right hemispheres. Each half is divided up into lobes, which have specific functions. The four lobes of each hemisphere, according to NIH, are:

The outer portion of the cerebrum is the gray matter, which is called the cerebral cortex. It is made up of unmyelinated nerve cells. It's the gray matter where we do our thinking. It's the part of your brain that is processing the information on this page as you read it.

Beneath the gray matter is white matter, which is made up of nerve fibers that are myelin coated and connect the cerebral cortex to everything else. Myelin insulates the nerve sheath, allowing impulses to travel much faster. Damage to myelin is associated with diseases such as multiple sclerosis. (Read about "Multiple Sclerosis")

Covering the entire brain and the spinal cord are the meninges. They consist of three layers. The outer layer is called the dura mater, the middle layer is the pia mater and the inner most layer is the arachnoid. Infection of the meninges is called meningitis. (Read about "Encephalitis & Meningitis")

Following the links below will give you more information on some conditions that affect the brain and nervous system, including mental health conditions.

Acoustic neuroma: see Balance Disorders

Addiction: see Addiction

Alzheimer's: see Alzheimer's Disease

Anencephaly: see Neural Tube Defects

Aneurysms: see Aneurysm

Anxiety disorder: see Anxiety

Aphasia: see Aphasia

Arachnoid cysts: see Arachnoid Cysts

Arteriovenous malformations (AVMs): see Vascular Lesions of the Central Nervous System

Asperger's disorder: see Autism Spectrum Disorders

Astrocytomas: see Brain Tumors

Attention deficit hyperactivity disorder: see ADHD

Autism: see Autism Spectrum Disorders

Balance disorders: see Balance Disorders

Bell's palsy: see Bell's Palsy

Bipolar disorder: see Depressive Illnesses

Birth defects: see Birth Defects

Brain anatomy: see The Brain

Brain stem gliomas: see Brain Tumors

Brain tumors: see Brain Tumors

Broca's aphasia: see Aphasia

Capillary telangiectases: see Vascular Lesions of the Central Nervous System

Cavernous malformations: see Vascular Lesions of the Central Nervous System

Cerebral palsy: see Cerebral Palsy

Charcot-Marie-Tooth disease (CMT): see Neuromuscular Diseases

Childhood disintegrative syndrome: see Autism Spectrum Disorders

Chronic pain: see Chronic Pain

Concussion: see Head Injury

Craniopharyngiomas: see Brain Tumors

Creutzfeldt-Jakob disease: see Creutzfeldt-Jakob Disease

Cysts, arachnoid: see Arachnoid Cysts

Cysts, spinal: see The Spine

Dementia: see Dementia

Depression: see Depressive Illnesses

Developmental disorders: see Autism Spectrum Disorders

Down syndrome: see Down Syndrome

Dyslexia: see Dyslexia

Dysthymia: see Depressive Illnesses

Dystonia: see Dystonia

Dystrophies: see Neuromuscular Diseases

EEG - electroencephalograph: see EEG - Electroencephalograph

Encephalitis: see Encephalitis & Meningitis

Encephaloceles: see Neural Tube Defects

Encephalopathy: see Encephalopathy

Epilepsy: see Epilepsy

Fainting: see Syncope (Fainting)

Fluent aphasia: see Aphasia

GBS (Guillain-Barre syndrome): see Guillain-Barre Syndrome

Germ cell tumors: see Brain Tumors

Global aphasia: see Aphasia

Guillain-Barre syndrome: see Guillain-Barre Syndrome

Headaches: see Headaches

Head injury: see Head Injury

Huntington's disease: see Huntington's Disease

Hydrocephalus: see Hydrocephalus

Inflammatory myopathies: see Neuromuscular Diseases

Lyme disease: see Lyme Disease

Mad cow disease: see Mad Cow Disease

Medulloblastomas: see Brain Tumors

Meningiomas: see Brain Tumors

Meningitis: see Encephalitis & Meningitis

Mental health: see Mental Health

Migraine: see Migraine Headaches

Motor neuron diseases: see Neuromuscular Diseases

Multiple sclerosis: see Multiple Sclerosis

Muscular dystrophies: see Neuromuscular Diseases

Myasthenia gravis: see Neuromuscular Diseases

Myopathies: see Neuromuscular Diseases

Nervous system: see Nervous System

Neural tube defects: see Neural Tube Defects

Neurofibromatosis: see Neurofibromatosis

Neuromuscular diseases: see Neuromuscular Diseases

Neuromuscular junction diseases: see Neuromuscular Diseases

Neuropathy: see Peripheral Neuropathy

Neuropathy, diabetic: see Diabetes

Neurosurgery: see Neurosurgery

Non-fluent aphasia: see Aphasia

Obsessive compulsive disorder (OCD): see OCD

Oligodendrogliomas: see Brain Tumors

Panic disorder: see Panic Disorder

Paresthesia: see Paresthesia

Parkinson's disease: see Parkinson's Disease

Peripheral nerve diseases: see Neuromuscular Diseases

Peripheral neuropathy: see Peripheral Neuropathy

Pervasive developmental disorders: see Autism Spectrum Disorders

Phobias: see Phobias

Pineal region tumors: see Brain Tumors

Post-polio syndrome: see Post-Polio Syndrome

Postpartum depression: see Depressive Illnesses

Post-traumatic stress disorder (PTSD): see PTSD

Prion diseases: see Encephalopathy

Rett syndrome: see Autism Spectrum Disorders

Schizophrenia: see Schizophrenia

Schwannomas, brain: see Brain Tumors

Seasonal affective disorder (SAD): see Depressive Illnesses

Seizures: see Seizures

Shaken baby syndrome: see Head Injury

Shingles: see Shingles

Social phobia: see Social Phobia

Spina bifida: see Neural Tube Defects

Spine: see The Spine

Stroke: see Stroke

Stuttering: see Stuttering

Suicide: see Suicide Prevention

Syncope: see Syncope (Fainting)

Tay-Sachs disease: see Tay-Sachs Disease

TIA's: see Stroke

Tourette syndrome: see Tourette Syndrome

Transmissible spongiform encephalopathies (TSE): see Encephalopathy

Traumatic brain injury (TBI): see Head Injury

Tumors, brain: see Brain Tumors

Tumors, spine: see The Spine

Venous malformations: see Vascular Lesions of the Central Nervous System

Vertigo: see Balance Disorders

Vestibular schwannoma: see Balance Disorders

Wernicke's aphasia: see Aphasia

Wilson's disease: see The Liver

All Concept Communications material is provided for information only and is neither advice nor a substitute for proper medical care. Consult a qualified healthcare professional who understands your particular history for individual concerns.

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By printing and/or reading this article, you agree that you accept all terms and conditions of use, as specified online.