The brain is a complex three-pound organ that controls thought, memory, emotions, touch, breathing etc. There are various parts of the brain in the human body that regulate bodily functions. Thus, the brain and spinal cord together make up the central nervous system or (CNS).
Moreover, you’ll be astonished to know that 60% of the brain comprises human fat. At the same time, the remaining 40% is a combination of water, protein, salts and carbohydrates. In addition, the brain is the essential organ of the human body, which connects all other organs.
The brain allows us to receive information through our five senses: smell, sight, touch, taste and hearing. And, there are three parts of the brain, namely, the cerebrum, cerebellum and brainstem.
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Parts of the Brain and their Functions
As we have mentioned earlier, the human brain is divided into three parts. So let us know more about them and how these organs function.
Cerebrum
The cerebrum is the largest part of the brain and consists of the right and left hemispheres. In addition, it performs essential functions like hearing, touch, sight, emotions, learning, speech etc.
Moreover, the cerebrum is divided into two halves: the left hemisphere and the right hemisphere.
Right brain- Left brain
The right and left cerebrum of the hemispheres are joined by the bundle of fibres known as the corpus callosum, which transfers messages from one part of the brain to another. So if a stroke occurs on the right or left side of the brain, then that particular side of arms and legs gets paralyzed.
But not all functions of hemispheres are similar. Like left hemisphere controls speech, arithmetic and writing. On the other hand, the right hemisphere controls spatial ability, musical and creative skills. The cerebrum is divided into four lobes.
Lobes of the Brain
The cerebral hemispheres divide the brain into lobes. And each hemisphere has four lobes, namely, frontal, parietal, occipital and temporal.
- Frontal Lobe
The frontal lobe interprets emotions, speech, behaviour, body movement, judgment, problem-solving, and intelligence.
- Parietal Lobe
The parietal lobe interprets the language, touch, sense of pain, vision, hearing, memory, spatial ability and visual perception.
- Occipital Lobe
This part of the brain is mainly responsible for interpreting the vision (light, movement, colour).
- Temporal Lobe
The temporal lobe is responsible for language understanding, memory, sequence and organization.
Cerebellum
The cerebellum is located just under the cerebrum. Its main functions are to coordinate muscle movements, maintain balance and posture. It is a fist-size part of the brain and is located at the back of the head.
In addition, the cerebellum consists of two hemispheres, just like the cerebral cortex. The outer part contains neurons, whereas the inner area communicates with the cerebral.
Brainstem
The brainstem acts as a link between the cerebrum and cerebellum to the spinal cord. Its main functions are breathing, heart rate, body temperature, wake and sleep cycles, digestion, sneezing, coughing, vomiting, and swallowing.
- Midbrain: The midbrain is a complex structure with a range of different neuron clusters like nuclei and colliculi and other structures. So these features allow various functions like hearing and movement to calculating responses and environmental changes.
- Pons: The pons acts as a bridge between the midbrain and the medulla. Moreover, it helps in enabling activities like tear production, chewing, blinking, focusing vision, balance, hearing, facial expression etc.
- Medulla: The medulla is found at the bottom of the brainstem and connects the brain and the spinal cord. This part of the brain regulates functions like heart rhythm, breathing, blood flow, and oxygen and carbon dioxide levels. Also, it produces reflex activities like sneezing, vomiting, coughing and swallowing.
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Cells of the Brain
The brain consists of two cells: Nerve cells(neurons) and Glia cells.
Nerve Cells
There are various sizes and shapes of neurons. But all the neurons consist of a cell body, axon and dendrites. Nerve cells transfer the information through electrical and chemical signals from one part of the brain to another.
For instance, electrical wiring in a home where numerous wires are connected to get electricity at home. Similarly, neurons consist of many arms called dendrites that act like antennae and pick up other nerve cells’ message.
These messages then further pass to the cell body, determining whether the messages need to be passed further along. Lastly, messages arrive at the end of the axon, where sacs containing neurotransmitters open into the synapse.
Synapse is a tiny gap through which neurons communicate through the exchange of neurotransmitters.
Glial Cells
Glial (meaning glue) is responsible for providing neurons with nourishment, structural support and protection. Its interesting to know that glia cells are 10-50 times more than nerve cells or neurons, and it is one of the types of cells involves in the occurrence of brain tumours.
- Astroglia is the caretakers, and they regulate the blood to allow nutrients and to interact with neurons.
- Oligodendroglia cells produce a fatty substance called myelin that insulates axons and allows chemical messages to travel faster.
- Ependymal cells create the lining of the ventricles and secrete cerebrospinal fluid (CSF).
- Microglia are the immune cells of the brain, protecting it from invaders and cleaning up debris.
Meninges: Brain Coverings
The three layers of protective covering are called meninges to surround the brain and the spinal cord.
- Dura Mater: It is the outermost layer which is thick and tough. It consists of two layers: The periosteal layer, which provides a lining for the inner dome of the skull (cranium), and the meningeal layer is below that.
- Arachnoid Mater: It is a thin, weblike layer of connective tissue that does not contain blood vessels or nerves. And below the arachnoid mater is the cerebrospinal fluid or CSF. This fluid provides cushioning for the whole of the central nervous system (brain and spinal cord) and circulates these structures continuously to remove impurities.
- Pia Mater: It’s a thin membrane that covers the brain’s surface and follows its contours. In addition, the pia mater is rich with veins and arteries.
Deeper Structures Within the Parts of the Brain
Pituitary Gland
The pituitary gland is a pea-sized structure, and a part of the brain is found behind the nose’s bridge. Also, it is known as the “master gland”. Moreover, this gland governs the function of other glands in the body, regulating the flow of hormones from the thyroid, adrenals, ovaries and testicles.
Hypothalamus
The hypothalamus is situated above the pituitary gland. Also, it regulates body temperature, sleep patterns, controls hunger and thirst, and plays a role in aspects of memory and emotion.
Amygdala
Amygdala is a small almond-shaped structure that is located under each hemisphere of the brain. In addition, it regulates emotion and memory and is associated with the parts of the brain associated with stress and the “fight or flight” response when someone perceives a threat.
Hippocampus
It’s a seahorse-shaped organ located on the underside of each temporal lobe. It is responsible for memory, learning, navigation and perception of space. And, it receives messages from the cerebral cortex and may play a role in Alzheimer’s disease.
Pineal Gland
The pineal gland is situated deep inside the brain and attached to the top of the third ventricle. Moreover, it secretes melatonin, which helps in regulating circadian rhythms and the sleep-wake cycle.
Ventricles and Cerebrospinal Fluid
Ventricles in the brain are four open areas with passageways between them. Also, they open into the central spinal canal and the area beneath the arachnoid layer of the meninges.
The ventricles produce cerebrospinal fluid or CSF, a watery fluid that circulates in and around the ventricles, spinal cord, and between the meninges.
It becomes fascinating to understand the various parts of the brain and the functions these parts perform.
