Your brain receives information from the rest of your body in the form of electrical signals. The brain then integrates the information and generates electrical signals of its own, sending directions that allow you to move, react, think and learn. Composed of billions of microscopic cell bodies, your brain is gray, about the size of two fists, and weighs 3 lbs. Each anatomical division of your brain has a specific location, appearance and function.
Cerebrum
The largest and outermost layer of your brain is called the cerebrum. Covered in folds called gyri and grooves called sulci, the cerebrum looks like a cauliflower head. Running along the middle of the cerebrum is the longitudinal cerebral fissure, which divides the cerebrum into right and left hemispheres. Each hemisphere is further divided into four lobes: the frontal lobes, then the parietal and temporal lobes, followed by the occipital lobes in the back. Your cerebrum plays many different roles, including processor of input from your eyes, nose and mouth. It is responsible for your thoughts, emotions and decision-making.
Diencephalon
Underneath your cerebrum is the diencephalon, a smaller structure composed of the thalamus and hypothalamus. The thalamus relays information to and from the rest of the brain, and the hypothalamus regulates your body temperature, hunger and thirst, and controls the release of hormones.
Brainstem
The narrow structure that connects the rest of the brain to the spinal cord is called the brainstem. From top to bottom, the parts of the brainstem are the midbrain, pons and medulla oblongata. Together, these structures control sleeping, heart rate, breathing, digestion and other unconscious body processes.
Cerebellum
Your cerebellum is a mass of brain tissue located beneath the cerebrum and behind the brain stem. Like the cerebrum, the cerebellum is made up of two hemispheres. A structure known as the vermis connects the hemispheres. By integrating information about your body's position in space, it directs your posture and balance and allows you to make precise movements.
Meninges
To protect it from injury, three thin, almost invisible layers called meninges surround your brain. The delicate layer that touches the surface of your brain is called the pia mater. Covering the pia mater is the arachnoid mater. The top layer is the strongest and is called the dura mater. Between the pia and arachnoid layers lies a narrow space known as the subarachnoid space. This is where your cerebrospinal fluid, or CFS, is located. Your CFS cushions your brain and provides it with nutrients.
References
- BBC Science and Nature: Human Body and Mind. Organs - Brain
- "Clinically Oriented Anatomy;" Keith Moore; 6th Ed. pp. 865, 878.
