Dismiss Modal

Definition

Understanding the Brain

Choose a preferred language

The brain controls the entire body. The main areas of the brain include the cerebrum, cerebellum, forebrain, and brain stem. The cerebrum is divided into 2 halves that have 4 parts, called lobes. The 4 lobes are the frontal lobe, temporal lobe, parietal lobe, and occipital lobe. Different areas of the brain have different jobs. Some parts of the brain control basic things like breathing, blood pressure, and heartbeat. Other parts control more complex jobs, such as moving, thinking, speaking, the 5 senses, and memory.

Side view of head and brain.


Inside the skull

Under the scalp and the skull, a tough membrane (the dura) surrounds the brain. Beneath the dura, cerebrospinal fluid (CSF) cushions the brain and circulates in the subarachnoid space. Arteries carry oxygen-rich blood and nutrients throughout the brain. Without this blood, brain tissue quickly dies. The brain is made up of about 100 billion cells called neurons. These neurons allow the brain to do its many jobs.

Not pictured here is the forebrain. This part of the brain contains the thalamus, hypothalamus, and pituitary gland. The thalamus sends impulses from the sense organs to the cortex. The hypothalamus controls hunger, thirst, temperature, aggression, and sex drive. It also controls the pituitary gland, which controls the secretion of many hormones.

© 2000-2026 The StayWell Company, LLC. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare professional's instructions.

Make an Appointment

Make an Appointment

Find a Doctor

Find a Doctor

Find a Location

Find a Location

Related Services

Stroke & Neuroscience Center

Related Articles
Read article
Brain Health
Anatomy of the Brain

Learn about the brain, its parts, each part's functions, and how the brain is protected.

Read article
Brain Health
Normal Lumbar Puncture

Read on to learn how to care for yourself at home after a lumbar puncture.

Read article
Urgent Care
Jaw Fracture

You have a broken jaw, or mandible bone. This is called a jaw fracture. It may be a minor break in the bone. Or you may have a major break, with the bone moving out of place. Learn how to care for the fracture as you heal.

Read article
Brain Health
Safety During a Seizure

Let family and friends know what to expect and how to react when you have a seizure. This helps keep them calm and you safe. Here are some pointers for loved ones.