The human brain is responsible for overseeing an entire network of nerves that relay messages throughout the body, regulating every aspect of its activity. Our brains are complex and have evolved specialized structures to handle particular types of information. Information coming into and exiting the brain often follows a specific pathway that is routed through several of these structures, allowing for an integrated response.
Cerebrum
The cerebrum consists of two large hemispheres, left and right. It is subdivided into four lobes: the frontal, parietal, temporal and occipital. The frontal lobe is responsible for many high-order cognitive functions, including the ability to recognize and speak language. It also regulates an individual's personality and temperament. The parietal lobe is an area that helps to interpret sensory information associated with touch and taste. The temporal lobe contains the amygdala, a patch of tissue important in regulating emotions associated with fear. Also in the temporal lobe is the hippocampus, which is the primary center for memory formation. The temporal lobe regulates auditory and balance information, while the occipital lobe regulates visual information.
Thalamus
The thalamus is a structure found inside of the brain, beneath the cerebrum. It is the first place that sensory information is routed to on its way into the nervous system. The thalamus is responsible for sending this information on to other areas that are specialized to deal with it; for example, incoming visual information is routed from the thalamus to the occipital lobe of the cerebrum.
Hypothalamus
The hypothalamus is found below the thalamus and helps to regulate metabolic functions like sleep-wake cycles and body temperature. It is connected to and communicates with an important endocrine structure, the pituitary gland, to regulate hormone secretion. The hypothalamus contains two small lumps of tissue called mammillary bodies that are important in memory formation.
Epithalamus
The epithalamus is found behind the thalamus. It is a relatively small patch of brain tissue responsible for relaying information to the pineal gland. This endocrine gland releases hormones that regulate appetite, sex drive and sleep cycles in response to daylight.
Tectum
The tectum, which is Latin for "roof," is the top part of the human midbrain. It is so named because it forms the roof of the cerebral aquaduct. The tectum contains the corpora quadrigemina, a pair of small tissue outgrowths responsible for motor output responses due to auditory and visual information input.
Cerebral Aquaduct and Ventricles
The brain contains four cavities called ventricles that are connected by a cerebral aquaduct. The ventricles are lined with specialized cells called ependymal cells, which secrete cerebral spinal fluid, or CSF. It helps to support the brain's neurons by providing nutrients.
Tegmentum
The tegmentum is the bottom part of the midbrain and is separated from the tectum by the cerebral aquaduct. It has a cluster of cells called the red nucleus, which helps to regulate movement. It also processes pain information in an area called the periaquaductal gray. Finally, it contains a structure that tells the body's muscles when to stop moving--the substantia nigra. The muscle tremors characteristic of Parkinson's disease are the result of cell death in this area.
Cerebellum
The cerebellum, or "little brain," is located beneath the occipital lobe of the cerebrum. The cerebellum coordinates the movement of muscles so that they are stimulated in a specific order that will result in the desired action. Without cerebellar control, movement is clumsy and jerky.
Pons
The pons is a structure of the hindbrain that helps to regulate posture, sleep and respiration. It is found below the cerebellum and receives cerebellar output before the information is routed out to the body's muscles.
Medulla Oblongata
The medulla oblongata is the bottom-most structure of the brain. Below the medulla oblongata is the spinal cord. The medulla is involved in controlling voluntary movement, filtering auditory information, sending sensory information directly to the thalamus and helping other parts of the brain to regulate balance and the sensation of taste. It also contains a special cluster of cells referred to as the Raphe nucleus. This structure regulates moods and wakefulness.
References
- "Anatomy and Physiology: The Unity of Form and Function (5th Edition)"; Ken Saladin; 2010
- "Neuroscience: Exploring the Brain (3rd Edition)"; Mark Bear, Barry Connors and Michael Paradiso; 2007
