Brain Nerve

In animals, the brain is the control center of the central nervous system, responsible for behavior. In mammals, the brain is located in the head, protected by the skull and close to the primary sensory apparatus of vision, hearing, equilibrioception (balance), sense of taste, and olfaction (smell).

While all vertebrates have a brain, most invertebrates have either a centralized brain or collections of individual ganglia. Some animals such as cnidarians and echinoderms do not have a centralized brain, and instead have a decentralized nervous system, while animals such as sponges lack both a brain and nervous system entirely.

Brains can be extremely complex. For example, the human brain contains roughly 100 billion neurons, linked with up to 10,000 connections each.

Human brain has three main components - the cerebrum (which consists of the left and right cerebral hemispheres), the cerebellum, and the brain stem. The cerebral hemispheres of the brain make up the largest part of your brain. The cerebellum is the structure located behind the brain stem, and the brain stem is the lowest section of the brain and is connected to the spinal cord.