The human brain: its anatomy, functions, and diseases

Anatomy of the human brain

What is the human brain?

The brain is a vital and complex organ that is protected by the skull and brain membranes (meninges). This organ consists of a number of tissues and billions of supporting nerve cells and is connected to the spinal cord. Together with the spinal cord and nerves, the brain is the command center and nervous system of the human being.

As part of the nervous system, the brain has many important functions. This organ controls everything that happens in the body, such as thoughts, memories, speech, feelings, sight, hearing, arm and leg movements, and the functions of other organs in the body, including heart rate and breathing.

Some of the nerves in the brain go directly to certain parts of the body, such as the eyes, ears, and other parts of the head. However, several other nerves are connected to parts of the body through the spinal cord to control personality, senses, and other body functions, such as breathing to walking.

Parts of the human brain and their functions

The brain is divided into three main parts, namely the cerebrum (cerebrum), small brain (cerebellum), as well as the brain stem. These parts of the brain work together to run body systems. However, all three have specific functions, each of which is different. The following is an explanation of the parts of the brain and their functions:

Big brain

Big Brain (cerebrum / cerebrum) is the largest part in the anatomy of the human brain. Cerebrum function or cerebrum is to regulate movement and coordination of movements, touch, sight, hearing, assessment, reasoning, problem solving, emotions, and learning.

The cerebrum consists of two hemispheres, namely the right brain and the left brain. The right hemisphere of the brain controls movement on the left side of the body, while the left hemisphere regulates movement on the right side of the body.

The right and left brain are separated by grooves known as longitudinal fissures. The two sides of the brain are joined at the bottom by the corpus callosum, which sends messages from one part of the brain to another. The surface of the cerebrum has a distinctive fold appearance called cerebral cortex or the cerebral cortex.

The cerebral cortex is the outer thin layer of gray matter that encloses the brain, with a thickness of 2-3 mm. The creases or wrinkled ridges that form them are called gyri, while the gaps between them are called sulci.

Each hemisphere cerebrum and the cerebral cortex, both right and left, is made up of four sections called the lobes of the brain. The four brain lobes are:

• Frontal lobe. This is the part of the human brain that is in front of or behind the forehead. The forebrain functions to control thinking, planning, organizing, problem solving, memory, and short-term movement.
• Parietal lobe. This is the part of the brain above and behind the frontal lobe. Its function is to interpret sensory information, such as taste, temperature, and touch, as well as identify objects and understand spatial relationships (where a person's body is compared to objects around that person).
• Occipital lobe. This lobe is located at the back of the head that controls human vision.
• Temporal lobe. This section is behind and below the frontal lobe, just above the ear. This part of the brain plays an important role in regulating memory, speech and understanding.

Small brain

There is a large brain, there is also a part of the cerebellum called cerebellum or the cerebellum. Cerebellum is the part of the brain that lies behind and below the occipital lobe.

Function cerebellum or the cerebellum is to control and coordinate movement, maintain balance, and maintain posture. This part of the brain is important for helping a person perform fast, repetitive actions, such as playing video games. In addition, the cerebellum also plays a role in fine motor movements, such as painting.

Brain stem

Brain stem or brainstem is at the front cerebellum and is the part that is connected to the spinal cord. This part of the brain contains nerve fibers that carry signals to and from all parts of the body. In addition, the brain stem also regulates bodily functions such as heart rate, blood pressure, and respiration.

The human brain stem consists of three structures, namely the midbrain, pons, and medulla oblongata. The midbrain plays a role in regulating eye movement, while the pons is involved with the coordination of eye and facial movements, facial sensations, hearing, and balance.

While the medulla oblongata is the part of the brain that controls breathing, blood pressure, heart rhythm, and swallowing movements.

Other parts and structures of the human brain

Apart from the three main structures above, the anatomy of the brain also consists of other important parts with their respective functions. Here are the parts of the brain:

• Thalamus

The thalamus is the part of the human brain that is in the very middle or above the brain stem. This brain structure acts as a gatekeeper for messages passing between the spinal cord and the hemispheres of the brain.

• Hypothalamus

The hypothalamus is a small structure that is also in the midbrain, just below the thalamus. This part of the brain plays a role in controlling bodily functions, such as eating, sexual behavior, and sleep, as well as regulating body temperature, emotions, hormone secretion, and movement.

• Limbic system

The limbic system is a system in the brain that plays a role in controlling human emotions. Some of the parts of the brain that enter this system are the hypothalamus, part of the thalamus, amygdala (actively producing aggressive behavior), and the hippocampus (which plays a role in the ability to remember new information).

• The pituitary gland

The pituitary gland or pituitary gland is a small gland located at the base of the brain (behind the nose). Its function is to control hormone secretion, play a role in the growth and development of the body, and coordinate the functions of various organs of the body (kidneys, breasts and uterus) and other glands (thyroid, gonads, and adrenals).

• Ventricles

Ventricles are spaces or cavities in the brain that contain brain fluid or are called cerebrospinal fluid. There are four ventricular chambers connected to each other by a narrow channel or passageway.

• Pineal gland

The pineal gland is a gland that resides in the ventricles of the brain. These glands play a role in human sexual maturation. However, the other exact function of these glands in humans remains unclear.

• Cerebrospinal fluid

Cerebrospinal fluid is fluid that flows in and around the four ventricular spaces of the brain and between the two membranes lining the brain (meninges) and the spinal cord. This fluid protects the brain from injury to the brain as well as the spinal cord from injury to the spine.

In addition, the cerebrospinal fluid also carries nutrients to the brain and removes waste from the brain.

• The structure of human brain cells

The brain consists of two types of cells, namely neurons and glial cells. Neurons play a role in sending and receiving nerve impulses or signals, while glial cells provide support and nutrition, maintain homeostasis, form myelin, and facilitate signal transmission in the nervous system.

• Cranial nerves

Cranial nerves are 12 pairs of nerves that can be seen on the lower surface of the brain. Each of these nerves has a different specific function. Several cranial nerves carry information from the sense organs to the brain. Then there are those that control the muscles and some are connected to glands or internal organs, such as the heart and lungs.

Human brain development

The development of the human brain from infancy to old age

The brain is formed and developed since humans are still in the womb until adulthood. This brain development starts from the back of the brain and continues to the front or the frontal lobe.

Reporting from the website of the University of Washington, during the development period in the womb, 250,000 neurons (nerve cells) are added every minute. Each neuron will be connected with other neurons to form the nervous system with the help of fibers called dendrites and axons.

These nerve cells then continue to develop when the baby is born and then decline at a certain age.

• When the baby is born

At birth, the human brain already has nearly all the neurons it will have for the rest of their lives. However, it is the relationship between these cells that will continue to develop. Myelin or fatty substances that protect axons and help impulses move faster have also been produced by the brain near the spinal cord.

As for size, the average newborn brain is about a quarter of the size of an average adult brain. Its size then doubles in its first year of life. In terms of weight, the brain of the average newborn weighs about one pound or the equivalent of 500 grams and grows about two pounds or about 1 kg during childhood.

• Childhood

Entering the age of three, the human brain continues to grow to about 80 percent of the adult size. At this age, the brain actually has more than 200 percent of synapses. Synapse is a connection between axons and nerve cells that allows information to flow between them.

At the age of five years, the brain size of children has reached 90 percent of adults. Brain development also becomes sharper at this age. Every experience that the child feels will form a synapse.

• Teenage age

The size and weight of a teenager's brain does not differ much from that of an adult's. At this age, the myelin that is formed when the baby is born has a more complex sequence. The final series of myelin is located in the frontal lobe, precisely behind the forehead, which functions to make decisions, control impulses, and empathy.

However, this function is not as mature as adults. Therefore, many adolescents often experience confusion or unstable emotions.

• Adult age

When entering adulthood, the size and weight of the brain is much more developed than before. At this time, the average woman's brain weighs about 2.7 pounds, or the equivalent of 1.2 kg, while men about 3 pounds, or the equivalent of 1.3 kg.

At the age of 20 years, brain development in the frontal lobe is finally complete, especially in judgment. However, brain development will also begin to decline slowly at this age range. The body itself will form and eliminate nerve cells and brain cells.

• Elderly

By age 50, your memories start to get shorter or it becomes easier for you to forget things. This is because natural aging changes the size and function of the brain. The reduction in brain capacity is entirely due to the death of brain cells and synapses. The brain shrinks and the risk of various brain-related diseases will continue to increase.

Human brain disease

What diseases may occur in the brain?

When the brain is healthy, it works quickly and normally as it should. However, several diseases or disorders in the brain can appear that can interfere with your brain function and cause various disturbing symptoms, such as headaches, dizziness, or other signs related to the nervous system.

Some of the diseases or disorders that may occur in the human brain are:

• Brain injury

brain injury is a brain-related injury that affects a person physically, emotionally, and attitudes. There are two forms of injury that may occur, namely traumatic and nontraumatic injuries.

Traumatic injuries are generally caused by external factors, such as accidents, falls and so on. Meanwhile, non-traumatic injuries occur due to damage to the brain due to internal factors, such as lack of oxygen. Some examples of non-traumatic injuries include strokes, meningitis, encephalitis, seizures, brain tumors, and so on.

• Dementia and Alzheimer's

Dementia is a syndrome that involves memory loss and decreased intellectual function severe enough to interfere with an individual's ability to perform routine tasks. Meanwhile, Alzheimer's disease is the most common form of dementia and develops the fastest in the elderly.

• Parkinson's

Parkinson's disease is a brain disorder that causes body shaking (tremors) and difficulty walking, moving, and coordination.

• Epilepsy

Epilepsy is a disorder that occurs when brain activity becomes abnormal and causes seizures and loss of consciousness.

• Mental disorders

Mental disorders or often referred to as mental illnesses are medical conditions that develop and affect the brain. This condition can interfere with a person's thoughts, feelings, day-to-day functions, and ability to relate to other people. Several types of mental disorders that may occur, such as depression, anxiety, or psychotic disorders such as schizophrenia.

To find out your condition, you can do a symptom check with the health calculator available at Hello Sehat. However, you can also consult a doctor to determine certain changes or symptoms in yourself.

Facts and myths about the human brain

What are some of the myths about the brain?

The brain is the most complex organ in the body. Apart from anatomy and function, the brain also has a number of interesting myths that you need to know the truth. Here are the myths and their truth:

• Is it true that humans only use 10% of their brain power?

You may have heard the expression that humans only use about 10 percent of their brain power. However, this is just a myth. Humans literally use every part of their brain actively all the time.

The origin of this myth may be rooted in the aspect of the lack of self of every human being who feels that he has not fully utilized all his brain capabilities to the fullest.

• Is it true that a bigger brain means smarter?

Many people say, people who have a bigger brain are smarter. However, this is not entirely true. In fact, a large brain size is no guarantee for someone to have a high IQ. From various studies concluded, brain volume may play a role in the level of intelligence, but the relationship is very small.

Another interesting brain fact

Apart from the myths above, there are some other interesting facts about the brain that you may not know. Here are the facts:

• About 60 percent of the human brain is made of fat. These fatty acids are very important for brain performance, because it is also important to add fatty acid nutrients to the brain.
• The storage capacity of the human brain is almost unlimited. Research shows that the human brain is made up of about 86 billion neurons that form connections and can combine to increase storage capacity.
• Brain information travels up to 268 miles per hour.
• The harder you think, the more oxygen your brain will use from the blood, up to 50 percent.
• The human brain has the ability to generate about 23 watts of power (enough to power a lamp). This power can be obtained with adequate rest, while lack of sleep can increase the buildup of protein in the brain, which is associated with Alzheimer's disease.
• The brain has the ability to learn and grow with age. This process is called neuroplasticity, that needs to be practiced on a regular basis, such as by learning new things that make you think.