Brain Anatomy

When we’re born, our brains weigh about one pound, doubling in size over the course of our childhoods. By the time we reach adulthood, our brains are even larger: the average adult male brain weighs about three pounds, while the average female brain clocks in around 2.7. The brain serves a number of functions vital to life, including receiving messages through our five senses of smell, hearing, sight, taste, and touch. And its anatomy serves as a brilliant blueprint for its complex functions.

The brain has several major components, each a distinct role:

  • The cerebellum is found in the back of the brain, underneath the occipital lobes. Its function is to fine-tune motor activities (for example, finger movements while painting or performing surgery). The cerebellum also helps you maintain your balance and posture, and plays a major role in rapid, repetitive actions such as those involved in playing video games. 
  • The brainstem is the brain’s lower extension, and is found in front of the cerebellum and connected to the spinal cord. It’s made up of three structures: the midbrain, pons, and medulla oblongata. The brainstem’s function is the relay messages between various body parts and the brain’s cerebral cortex; several primitive functions necessary for survival occur here. The brainstem is also where 10 of the 12 cranial nerves find their origins.
  • The cerebrum forms the largest portion of the brain and is divided into two main sections: the right and left cerebral hemispheres. Often times, people will use the term “cerebrum” to describe the brain as a whole. The brain’s two sides are connected by the corpus callosum, which delivers messages between the two. The cerebrum’s surface is home to billions of neurons and glia that form the cerebral cortex together.
  • The hypothalamus is a small structure that holds nerve connections which function to send messages to our pituitary glands. It serves to handle information coming in from the autonomic nervous system, which is largely involved in unconscious activities, such as digestion and sexual arousal. The hypothalamus is also involved in regulating body temperature, movement, hormone secretion, and emotions.
  • There are 12 pairs of cranial nerves that find their origins in the brain; each is responsible for highly specific actions and activities.

The brain is also split up into four distinct lobes:

  • The frontal lobes are the largest of the four lobes, and are responsible for a variety of diverse functions, such as voluntary movement, behavioral and intellectual functions, and speech. 
  • The occipital lobes are found in the back of the brain and allow us to receive and comprehend visual stimuli.
  • The parietal lobes interpret signals received in other parts of the brain such as memory, sensory, hearing, vision, and motor stimuli; these lobes work simultaneously as we take in our surroundings.
  • The temporal lobes are found on each side of the brain, around ear level; they’re divided into two parts: there are the bottom (ventral) hemispheres and side (lateral) hemispheres. An area on the right side plays a role in visual memory, helping us recognize faces and objects; an area on the left side plays a role in verbal memory, helping us remember and comprehend language. The rear of the temporal lobe helps us interpret other people’s reactions and emotions.

The Ezra full-body scan screens your brain for cancerous and precancerous states, as well as other actionable conditions such as aneurysms; you can learn more about our screening options here.