Brain Anatomy and How Does the Brain Work?

The brain, our most complex and vital organ, plays a significant role in human life. This organ is at the center of all processes, from acting without thinking to emotions and reflexes, and manages the body by processing millions of pieces of information in seconds. For this reason, its anatomical structure and how it works have always been a subject of curiosity. To satisfy your curiosity, we have created content titled “Brain Anatomy and How the Brain Works” for you. You can find detailed information by browsing our content. We wish you all healthy days and happy reading.

What is the Brain?

The brain is the most fundamental and complex organ of the central nervous system and forms the management and control center for all nerves in the body. Thus, it controls not only higher mental functions such as thinking, learning, memory, consciousness, emotions, and behavior, but also vital functions such as movement, balance, speech, vision, hearing, and the functioning of internal organs. In this context, the brain consists of billions of neurons, and these neurons are in constant communication with each other and with the spinal cord and peripheral nervous system via nerve fibers. At the same time, motor signals that control the movement of voluntary muscles, such as facial muscles, also originate in the brain and are transmitted to the muscles via nerves. In short, the brain is a coordinated, harmonious, and holistic control center that coordinates all bodily functions through the nervous system.

What is the Brain Made Of?

The brain has an extremely complex structural and cellular organization and is primarily composed of nerve cells (neurons) and supporting cells (glial cells). These neurons are the main cells that transmit information via electrical and chemical signals; glial cells provide nutrition, protection, insulation, and functional integrity to neurons. In this context, brain tissue consists of two main parts: gray matter and white matter. Gray matter contains neuron bodies, while white matter consists of nerve fibers and facilitates communication between brain regions. This cellular structure is organized into anatomical sections such as the cerebrum, cerebellum, and brain stem. Furthermore, the brain is nourished by a rich network of blood vessels that supply it with oxygen and nutrients, and it is protected from external influences by the skull, meninges, and cerebrospinal fluid. All these structural components work together to enable the brain to perform both cognitive and motor functions flawlessly.

How Does the Brain Work?

The brain processes and manages all information coming from and going to the body through a complex network of communication between nerve cells. Stimuli received through the senses are transmitted to the brain via nerves, where they are analyzed, interpreted, and appropriate responses are generated in the relevant centers. In this process, neurons communicate with each other using electrical impulses and chemical messengers via synapses. This allows the brain to simultaneously control conscious thought and voluntary movement, as well as automatic functions such as breathing, heartbeat, and reflexes. Additionally, movement planning occurs in the motor cortex, and these plans are transmitted to the muscles via the spinal cord and peripheral nerves. Furthermore, the brain exhibits a dynamic structure that can adapt itself by constantly reorganizing neural connections during learning and memory processes. Thanks to this holistic working order, the brain functions as a central control mechanism that maintains the body's internal balance and adapts to the environment.

The Main Parts of the Brain and Their Functions

The brain has certain main parts and functions within itself. These parts have their own specific tasks. If we examine these parts of the brain, they are as follows:

Cerebral Cortex

The cerebral cortex is the outermost layer of the cerebrum and is responsible for higher cognitive functions. This structure consists of gray matter and is the center of higher mental activities such as thinking, consciousness, decision-making, problem-solving, speech, learning, and memory. It also contains motor areas where voluntary muscle movements are initiated and sensory areas where sensory information such as vision, hearing, and touch is processed. In addition, the cortex is divided into the frontal, parietal, temporal, and occipital lobes, allowing each function to specialize in specific regions. However, damage to this structure can lead to neurological conditions such as speech disorders, loss of movement, perception problems, and central-type paralysis affecting the facial muscles.

Brain Stem

The brain stem is the section located between the brain and the spinal cord that controls functions critical to life. This section consists of three main parts: the midbrain, pons, and medulla oblongata. Automatic and vital functions such as breathing, heartbeat, blood pressure, swallowing, and reflexes are controlled by the brain stem. Therefore, damage to the brainstem can cause serious neurological problems such as facial paralysis, difficulty swallowing, speech disorders, and changes in consciousness.

Cerebellum

The cerebellum is located in the back-lower part of the brain and is responsible for coordinating movements, balance, and regulating muscle tone. This structure ensures that voluntary movements are performed smoothly, fluidly, and in a balanced manner. Therefore, the cerebellum evaluates feedback from muscles and joints to adjust the timing and precision of movements, allowing fine and rapid muscle movements, such as facial expressions, to occur in harmony.

Brain Membranes

Brain membranes are a three-layered membrane system that protects and supports the brain against external influences. This membrane system consists of three parts. These are: the outer, hard dura mater; the middle, spider web-like arachnoid mater; and the innermost pia mater, which is in direct contact with the brain tissue. These membranes provide mechanical protection between the brain and the skull while also allowing the circulation of cerebrospinal fluid. Thus, the meninges form a protective barrier against infections and trauma; inflammation of these structures can lead to serious diseases such as meningitis.

Brain Lobes and the Functions They Control

• Frontal Lobe: The frontal lobe is the region located at the front of the brain and is responsible for the most advanced cognitive functions. This region performs tasks such as decision-making, planning, problem-solving, attention, personality traits, and the regulation of social behavior. The motor cortex, where voluntary muscle movements are initiated, is also located in this region; the movements of the face, arm, and leg muscles are controlled from here. In addition, damage to the frontal lobe can cause behavioral changes, attention and planning problems, speech difficulties, and central-type movement losses affecting the facial muscles.

• Parietal Lobe: The parietal lobe is located in the upper-middle part of the brain and plays a fundamental role in processing sensory information from the body. This region generally handles sensations such as touch, pressure, pain, temperature, and body position. Spatial perception, orientation, and body awareness are also important functions of the parietal lobe. This lobe integrates sensory information with motor planning to ensure that movements are performed correctly and consciously.

• Occipital Lobe: The occipital lobe is located at the back of the brain and is the center of visual functions. In this center, visual signals from the eyes are processed, interpreted, and understood in this lobe. For this reason, color, shape, movement, and depth perception are evaluated in different subregions of the occipital lobe. It also enables the recognition of visual information and its transmission to other brain regions. Consequently, damage to the occipital lobe can result in visual field loss, visual perception disorders, and, in some cases, visual hallucinations.

• Temporal Lobe: Finally, the temporal lobe is located on the sides of the brain and plays a critical role in hearing, language perception, and memory processes. It plays a particularly important role in distinguishing sounds. Therefore, damage to the temporal lobe can cause impairments in hearing perception, difficulty understanding spoken language, memory problems, and emotional changes.

Other Structures of the Brain

Pituitary Gland

The pituitary gland is one of the most important glands located at the base of the brain that regulates the body's endocrine system. It is often referred to as the “master gland” because it indirectly controls the release of many hormones, such as those related to growth, thyroid function, adrenal glands, reproductive organs, and milk production. However, dysfunction in the pituitary gland can lead to growth problems, hormonal imbalances, menstrual irregularities, and metabolic issues.

Hypothalamus

The hypothalamus is a vital structure located deep within the brain that acts as a bridge between the nervous system and the hormonal system. This structure plays a fundamental role in regulating body temperature, feelings of hunger and satiety, thirst, the sleep-wake cycle, and sexual behavior. It also controls hormone release by directing the pituitary gland. As a result, the hypothalamus is at the center of homeostasis mechanisms that maintain internal balance, and when this balance is disrupted, widespread effects can occur in the body's systems.

Amygdala

As part of the limbic system, the amygdala plays a significant role in processing emotions and particularly in the formation of fear, anxiety, and stress responses. It contributes to the formation of emotional memories and helps in the rapid assessment of perceived threats. The amygdala also links emotional responses to the autonomic nervous system and hormonal responses, enabling the body to respond appropriately to environmental threats. Thus, excessive or insufficient functioning of this structure can be associated with anxiety disorders and emotional regulation problems.

Hippocampus

The hippocampus is one of the limbic system structures that plays a critical role in learning and memory processes. It is responsible for transferring short-term information into long-term memory and supports spatial memory and navigation abilities. It also enables the contextual recall of past experiences. Since the hippocampus is sensitive to stress hormones, its functions may be negatively affected during prolonged stress, which can lead to memory problems.

Pineal gland

The pineal gland is a small gland located in the middle of the brain that regulates biological rhythms. This gland controls the sleep-wake cycle and seasonal biological rhythms by secreting the hormone melatonin. It is also sensitive to light levels and increases melatonin secretion in the dark. Therefore, pineal gland dysfunction may be associated with sleep problems, circadian rhythm disorders, and certain hormonal imbalances.

Ventricles and Cerebrospinal Fluid

The ventricles are a system of cavities located within the brain that contain cerebrospinal fluid (CSF). This fluid protects the brain from mechanical impact, aids in the transport of nutrients, and facilitates the removal of waste products. Therefore, blockages in the ventricular system or disturbances in CSF balance can lead to serious neurological problems such as increased intracranial pressure and hydrocephalus.

Blood Flow to the Brain

Blood flow, which is vital for meeting the brain's high metabolic needs and ensuring its continued functioning, is supplied through the carotid arteries and vertebral arteries. These arteries converge at the base of the brain, forming a safety net structure called the circle of Willis. This structure helps protect the brain against potential interruptions in blood flow. Thus, the blood reaching the brain carries oxygen and nutrients to nerve cells through capillaries, while also removing metabolic waste. On the other hand, a decrease or interruption in cerebral blood flow can cause neurons to rapidly lose function and lead to serious neurological conditions such as stroke.

What Disorders Can Affect the Brain?

There are many disorders that can affect the brain. These disorders occur in different parts of the brain and manifest themselves with different symptoms. If we examine these disorders in detail, they are as follows:

• Stroke

One of the most common disorders affecting the brain, stroke is a serious neurological condition caused by a sudden decrease or complete interruption in blood flow to the brain. This disruption in blood flow prevents brain cells from receiving oxygen and nutrients, leading to rapid cellular damage. This can lead to speech impairment, facial asymmetry, sudden weakness in the arms or legs, and changes in consciousness. Therefore, early intervention is vital to protect brain tissue.

• Brain Tumors

Another disorder that occurs in the brain is brain tumors. Brain tumors are known as benign or malignant masses that develop within or around brain tissue. These masses cause symptoms by putting pressure on the area they are located in or by disrupting the function of brain tissue, and can lead to persistent headaches, seizures, visual disturbances, and personality changes.

• Traumatic Brain Injury

Traumatic brain injury is a condition caused by direct or indirect damage to brain tissue resulting from head trauma. This condition can develop due to traffic accidents, falls, and blows, and can cause loss of consciousness, memory problems, attention deficit, and behavioral changes. In this context, traumatic brain injuries can cause temporary or permanent neurological effects depending on the severity of the injury.

• Epilepsy

Epilepsy is a chronic neurological disorder characterized by recurrent seizures caused by abnormal and uncontrolled electrical activity in the brain. These seizures can manifest as brief loss of consciousness, convulsions, or blackouts and, if left untreated, can cause permanent brain damage. Therefore, early treatment is essential in epilepsy.

• Facial Paralysis

Facial paralysis, which we have been encountering frequently lately, occurs as a result of the facial nerve that controls the facial muscles or the brain regions that control this nerve being affected. This condition can cause symptoms such as sudden weakness on one side of the face, loss of facial expression, inability to close the eye, and drooping of the corner of the mouth. As a result, facial paralysis can be central or peripheral in origin, and the recovery process varies depending on the underlying cause.

• Cerebral Palsy

Cerebral palsy is a permanent movement and posture disorder that develops due to brain damage that usually occurs before birth, during birth, or in early childhood. This disorder is characterized by stiffness, coordination problems, and limited voluntary movement.

• Sleep Apnea

Finally, sleep apnea is a sleep disorder characterized by repeated pauses in breathing during sleep. This condition prevents the brain from receiving sufficient oxygen and causes frequent awakenings throughout the night. It can also negatively affect attention, memory, and decision-making processes in the long term and may lead to other neurological disorders such as stroke.

The Brain's Primary Function and Control of Facial Muscles

The brain's primary function is to centrally and coordinately manage all bodily functions; within this scope, it has a broad range of control, from voluntary movements to sensory perception, emotional responses, and vital reflexes. In this way, the movement of facial muscles is also an important part of this central control, and signals originating in the motor cortex are transmitted to the facial muscles via the brainstem and facial nerve. Once transmitted to the facial muscles, mimic movements such as smiling, speaking, and raising the eyebrows occur in harmony with the brain's planning, timing, and coordination processes. Any disruption in the neural transmission chain can lead to facial paralysis, manifested as weakness or loss of movement in the facial muscles.

Brainstem and Facial Nerve (7th Cranial Nerve)

The brainstem and facial nerve (7th cranial nerve) play a central role in controlling facial movements. Specifically, the nucleus of the facial nerve is located in the pons section of the brainstem, and the nerve fibers originating from here transmit motor impulses to the facial muscles, enabling facial expressions. The facial nerve also plays a role in sensory and autonomic functions such as the anterior two-thirds of taste sensation and the secretion of tears and saliva. Therefore, the brainstem is a vital transition and control center that regulates the multifaceted functions of the facial nerve. Consequently, damage in this region can cause facial paralysis, presenting with symptoms such as weakness on one side of the face, loss of facial expressions, inability to close the eye, and changes in taste sensation. Therefore, the anatomical and functional integrity between the brainstem and the facial nerve is critically important for the healthy functioning of the facial muscles.

Sensory Feedback, the Brain, and Facial Paralysis

Sensory feedback is one of the fundamental pieces of information the brain needs for facial muscles to function correctly and in a controlled manner. This information—touch, pressure, and position sensations from the facial region—is transmitted to the brain via sensory nerves and integrated with motor control mechanisms. Thanks to this feedback, the brain can assess how much the facial muscles are contracting and what movement is occurring. Thus, in cases of facial paralysis, a decrease or impairment in sensory feedback can make it difficult for the brain to correctly direct the facial muscles and can negatively affect the recovery process. In addition, insufficient sensory input can disrupt the coordination of facial expressions, leading to asymmetry and loss of control. Consequently, increasing sensory awareness in facial paralysis rehabilitation is an important factor that supports the brain's learning and adaptation process.

If you would like to learn more about brain-related facial paralysis disorders, you can schedule a preliminary consultation with Dr. Berke Özücer and his team.