Weighing in at around 1.4 kg (3 pounds), our brain is the most complex part of the human body. Lying in the skull and bathed in protective fluid (called cerebrospinal fluid), it powers our intelligence, interprets our senses, initiates our body movement, controls our behaviour, and is the source of all the qualities that define our humanity. There are many parts that make up the structure and function of the brain, and this article will touch on some of these main parts and their associated functions.
In general terms, the brain is made up of 3 main parts: the cerebrum, the cerebellum and the brain stem.
The cerebrum (also referred to as the cerebral cortex) is the largest part of the brain, and it consists of 4 lobes – the frontal lobe, the temporal lobe, the parietal lobe and the occipital lobe. These have already been looked at in detail in a previous article, so for much more information please check out the previous article.
The cerebellum (translated literally as ‘little brain’ in Latin) is situated at the base of the skull, above the brainstem and beneath the occipital lobes of the cerebral cortex. It is associated with regulation and coordination of fine movement (movements using small muscle groups, such as those in the fingers), posture, muscle tone and balance. The cerebellum processes information from the brain and peripheral nervous system for balance and body/motor control.
The brain stem is located at the juncture of the cerebrum and the spinal column and is anterior to (in front of) the cerebellum. It relays information between the peripheral nerves and spinal cord to the upper parts of the brain, and is responsible for basic vital life functions such as breathing, heartbeat, and blood pressure. The structure consists of the midbrain, pons and medulla oblongata (or simply medulla):
- Midbrain – Involved in controlling responses to sight, eye movement, pupil dilation, regulation of muscle movement and hearing. A number of structures are located in the midbrain, such as the substantia nigra which is involved in the development of Parkinson’s Disease following neurodegeneration of its nerve cells.
- Pons – This is the largest part of the brain stem and is located below the midbrain. It is involved in arousal (e.g. acute stress like a threatening situation), breathing regulation, relaying sensory information between the cerebrum and cerebellum and sleep.
- Medulla – This is the lowest part of the brain, and acts as the control centre for the function of the heart and lungs. It helps control and regulate many autonomic functions such as breathing, digestion, heart and blood vessel function, swallowing, and sneezing.
An additional important structure is the limbic system, which is found buried within the cerebrum and above the brain stem. It is often referred to as the “emotional brain”. Its structures are involved in many of our emotions and motivations, particularly those that are related to survival such as fear and anger. The limbic system is also involved in feelings of pleasure that are related to our survival, such as those experienced from eating and sex. It consists of the thalamus, hypothalamus, amygdala and hippocampus:
- Thalamus – Mass of gray matter cells that relay sensory signals to and from the spinal cord and the cerebrum.
- Hypothalamus – A very small but important component of the brain. It plays a major role in regulating hormones, the pituitary gland, body temperature, the adrenal glands, and many other vital activities.
- Amygdala – Involved in emotional responses, hormonal secretions, and is responsible for determining which memories are stored and where the memories are stored in the brain.
- Hippocampus – Sends memories out to the appropriate part of the cerebral hemisphere for long-term storage and retrieves them when necessary. People who experience damage to the hippocampus have difficulty recalling events.
I hope this has given a brief overview of the main structures that make up our brain, and their associated functions.
For more information and a huge amount of detail on the brain’s anatomy, visit: https://www.thoughtco.com/anatomy-of-the-brain-373479