The human body is comprised of numerous organs, and while they all play an important role in overall health and well-being, there’s one organ that is more important that all the rest: the brain. This is because the brain is responsible for the function, not only of all other organs, but of all of the systems within the body.
From performing voluntary and involuntary actions, and from learning new things to applying acquired knowledge, and from expressing emotion and feeling, the human brain literally controls all aspects of the human body.
The brain is part of the central nervous system, and it functions as the control system of the human body. The brain connects to the spine, and it controls all functions, including breathing, blinking, digestion, the production of blood cells, movement, personality, speech, and all other key functions. The brain is the most complex – and most important – organ in the human bod.
The average adult brain weighs about 3 pounds. Sixty percent of the brain is comprised of 60 percent fat, and the remaining 40 percent consists of protein, salt, and carbohydrates. It isn’t a muscle, but rather the brain is composed of neural tissue.
Because of the intricate nature of its structure and function, the anatomy of the human brain is highly complex. A truly incredible organ, the brain receives, interprets, and directs information throughout the entire body, making it the control center for the entire human body. As mentioned, the brain is one of the main structures of the central nervous system, and it’s connected to the spinal cord, the second primary structure of the central nervous system.
The brain is categorized into three key divisions: the forebrain, the midbrain, and the hindbrain. The forebrain is the division of the brain that controls a wide range of functions, such as receiving and processing sensory information, thinking, perceiving, generating and comprehending language, and motor function control. The forebrain is further divided into two sections: • The diencephalon, which contains structures, including the telencephalon and the diencephalon, that are responsible for various functions, such as motor control, distributing sensory information, and controlling autonomic functions. • The telencephalon, which contains the cerebrum, and is the largest part of the brain. The vast majority of information processing occurs in the cerebral cortex The other two divisions of the brain, the midbrain and the hindbrain, make up the brainstem. The midbrain, also known as the mesencephalon, is the part of the brainstem that links the hindbrain to the forebrain. This part of the brain is responsible for visual responses, auditory responses, and motor function. Extending from the spinal cord, the hindbrain is comprised of the metencephalon and the myelencephalon. The former holds key structures, such as the cerebellum and the pons, and these regions help maintain balance and equilibrium, coordinated movement, and the transmission of sensory information. The medulla oblongata is located in the myelencephalon, which controls automatic functions or involuntary actions, such as breathing, digestion, blinking, and heart rate.
The brain is composed of several structures that have numerous functions. The major structures of the brain and some of their key functions include the following: • Basal ganglia. Controls cognition and voluntary movement. • Brainstem. Transmits information between the spinal cord and the peripheral nerves to the upper portions of the brain. It also consists of the midbrain, the medulla oblongata, and the pons. • Central Sulcus. Also known as the Fissure of Rolando, this is a deep grove that delineates the frontal and parietal lobes. • Boca’s Area. This part of the brain is responsible for speech production, as well as language comprehension. • Cerebellum. The cerebellum controls movement and coordination, and it maintains equilibrium and balance. • Cerebral cortex. Consists of the outer part of the cerebrum and divided into cerebral cortex lobes, the cerebral cortex both receives and processes sensory information. • Cerebral cortex lobes. The cerebral cortex is comprised of several lobes, including the: o Frontal lobes, which play a part in decision-making, planning, and problem solving. o Occipital lobes, which are responsible for vision and color recognition. o Parietal lobes, which receive and process sensory information. o Temporal lobes, which process emotional responses, speech, and memory. • Cerebrum. The largest part of the human brain, the cerebrum contains the gyri, which are folded bulges that create deep furrows within the brain tissue. • Cranial nerves. There are 12 pairs of nerves that originate in the brain. These nerves exit the skull and are connected to the head, neck, and torso. • Corpus Callosum. These thick bands of fibers connect the right and left hemispheres of the brain. • Fissure of Sylvius. Also known as the Lateral Sulcus, this part of the human brain is a deep groove that seperates the parietal and temporal lobes. • Limbic structures. These structures make up the limbic system, which is the part of the human brain that is involved in emotional and behavioral responses; particularly responses that are necessary for survival, such as eating, reproduction, caring for babies and children, and the fight or flight response. The limbic structures are buried deep within the brain, below the cerebral cortex, just above the brainstem. • Medulla Oblongata. The lower part of the brainstem, the Medulla Oblongata aids in autonomic function control. • Meninges. These membranes cover and protect the brain, as well as the spinal cord. • Pineal gland. Some refer to the pineal gland as the “third eye”. It is an endocrine gland that plays a key part in biological rhythms, and it secretes melatonin, a vital hormone. • Pituitary gland. Another endocrine gland, the pituitary is involved in maintaining homeostasis and regulates other glands of the endocrine system. • Wernicke’s area. This part of the brain comprehends spoken language. • Pons. The pons relays sensory information between the cerebrum and the cerebellum.
The midbrain is also comprised of several components, including the following: • Cerebral peduncle. The anterior part of the midbrain, the cerebral peduncle consists of large collections of nerve fiber tracts, and these nerves connect to the forebrain, as well as the hindbrain. • Reticular formation. This part of the midbrain contains the nerve fibers that are situated within the brainstem, as well as a part of the tegmentum. It aids in the regulation of sleep and awareness. • Substantia nigra. This portion aids in voluntary movement control and regulates the mood. • Tectum. The tectum is the dorsal region of the mesencephalon, and it aids in visual and auditory reflexes. • Tegmentum. The ventral part of the mesencephalon, the tegmentum includes the reticular formation, as well as the red nucleus.
The ventricular system of the brain is a connecting system that is comprised of internal brain cavities that are filled with cerebrospinal fluid. The ventricular system is comprised of the following: • Aqueduct of Sylvius. This canal is located in between the third and fourth ventricles. • Choroid plexus. This part generates cerebrospinal fluid. • Fourth ventricle. This canal runs between the pons, the medulla oblongata, and the cerebellum. • Lateral ventricle. Located in both brain hemisphere, the lateral ventricle is the largest of the brain ventricles.
As can be seen from the above information, the human brain is an intricate system that is comprised of numerous parts, and these parts not only work with other parts of the brain, but they also work with other parts of the body. The brain is the most important organ, as it functions as the command center.
The brain is responsible for all key functions – from major to minor – that the human body performs, including the ability to speak, process and recall information, make decisions, and emotional responses. While the brain is responsible for the same key functions in each individual, it is important to remember that every brain is unique. It is also important to remember that the brain constantly changes, and that it is highly sensitive to its environment.
To further illustrate the importance of the brain, below is an overview of the different parts of the human brain and the key functions that each part is responsible for. Functions of the Frontal Lobe • Attention • Self-monitoring • Concentration • Organization • Speaking • Awareness of abilities and limitations • Motor planning, as well as motor initiation • Personality • Behavior inhibition • Mental flexibility • Problem solving • Emotional responses • Judgement • Planning Functions of the Temporal Lobe • Memory • Sequencing • Language processing • Auditory processing (hearing) • Organization Functions of the Brain Stem • Consciousness • Breathing • Heart rate • Arousal • Digestion • Sleep and wake cycles Functions of the Cerebellum • Balance and coordination • Visual perception • Skilled motor activity Functions of the occipital lobe • Vision processing and comprehension Left and Right Traits The human brain and the functions that it is responsible for is further categorized in two sides: the left side and the right side. The traits that are associated with each side of the brain include the following: • Traits of the Left Side of the Brain o Analytical thinking o Logical thinking o Precision o Organization o Detachment o Literal comprehension • Traits of the Right Side of the Brain o Creativity o Imagination o Intuition o Conceptualization o Empathy o Figurative understanding and communication
Since the brain is the command center and controls all functions of the human body, damage to this organ can have profound impacts on an individual. Strokes and brain injuries, which can range from mild to moderate to severe, are two conditions that can negative impact the brain, and thus decrease its function. In severe conditions, brain death can occur. While an individual can technically be alive following brain death, he or she will never regain consciousness. In order to remain alive, a brain dead individual will require life support, which will artificially control the function of the heart and the lungs.
Decreased activity to the brain does not always cause brain death; however, any type of decreased activity can impact an individual. The following is a breakdown of some of the different ways in which decreased activity or injury to each part of the brain can affect an individual.
If the frontal lobes are injured, a person’s ability to control emotions, impulses, and behaviors can be impacted. An individual may also have a hard time speaking and/or recalling events.
Decreased activity or injury to the temporal lobe can make it difficult for an individual to communicate or recall information.
Following an injury or decreased activity to the parietal lobe, a person can have sensory difficulties. For example, they may have a hard time processing the sense of touch, their vision may be blurred, they may have ringing in their ears, or they may experience a foul taste.
Following an injury or decreased activity to the cerebellum, a person may experience difficult with his or her balance, coordination, and/or movement.
Following an injury or decreased activity to the occipital lobe, a person may have difficulty seeing, or he or she may not perceive the size and shape of objects properly.
Because the brain stem controls the involuntary functions that are vital for survival, such as breathing and heart rate, an injury or decreased activity to this part of the brain can result in brain death, and may require artificial life support.
As mentioned above, in addition to the different sections of the brain, this vital organ is also divided into two sides: the left side and the right side. Each side plays a part in how a person thinks, behaves, and reacts. As such, injuries to or decreased activity in the left or right side of the brain can also have negative impacts on a person. These negative impacts can include the following:
• Speech or verbal output difficulties • Difficulty comprehending language • Difficulties with speech • Catastrophic reactions, such as anxiety or depression • Difficulties with sequencing • Reduced control of the right side of the body
• Visual-spatial difficulties • Deficits with visual memory • Decreased awareness of deficits • Inability to think on a grander scale; to see things as a bigger picture, so to speak • Alterations in the perception of creative thought and music • Left neglect, or not paying attention to the left side of the body • Reduced control of the left side of the body As can be summarized from the information provided above, decreased brain function can cause a variety of complications, and these complications can impact a person’s life in a myriad of ways. The extent of the impact varies and depends on several functions, including the cause of the decreased brain function, the part(s) of the brain that were impacted, and the severity of the damage.