Components of the Brain
Cerebrum
The cerebrum (English: Cerebrum) constitutes the largest portion of the brain and is divided into the right and left cerebral hemispheres. It is responsible for higher cognitive functions, including the interpretation of touch, vision, and hearing, as well as speech, reasoning, emotions, learning, and fine motor control.
Notably, the two hemispheres are interconnected by a bundle of fibers known as the corpus callosum (English: Corpus Callosum), which facilitates communication between them. Each hemisphere governs the opposite side of the body, meaning that a stroke occurring in the right hemisphere may result in weakness or paralysis of the left arm or leg.
Typically, the hemispheres do not share identical functions. The left hemisphere predominantly manages speech, comprehension, calculation, and writing, while the right hemisphere is more involved in creativity and artistic and musical skills. Approximately 92% of individuals predominantly use their left hemisphere for language and handedness.
Each hemisphere is further divided into major regions known as lobes, each associated with different functions:
- The frontal lobes (English: Frontal lobes) are among the largest lobes, positioned at the front of the brain, and coordinate high-level behaviors, including motor skills, problem-solving, judgment, planning, and attention. They also regulate emotions and control heart rate.
- The parietal lobes (English: Parietal lobes) are located behind the frontal lobes and are involved in organizing and interpreting sensory information received from other parts of the brain.
- The temporal lobes (English: Temporal lobes) are situated on either side of the head at the level of the ears and coordinate specific functions, including visual memory (like face recognition), verbal memory (such as language comprehension), and the interpretation of emotions and reactions from others.
- The occipital lobes (English: Occipital lobes) are positioned at the back of the brain and are linked to the interpretation of visual stimuli and information. The primary visual cortex, responsible for receiving and interpreting signals from the retina, is located within this lobe. Damage to the occipital lobes can lead to visual problems, such as difficulty recognizing objects, inability to distinguish colors, and challenges with word recognition.
Brain Stem
The brain stem (English: Brain Stem) is located in front of the cerebellum and connects to the spinal cord. It consists of three main parts:
- The midbrain (English: Midbrain) helps control eye movement and processes visual and auditory information.
- The pons (English: Pons) is the largest section of the brain stem, situated below the midbrain. It consists of a cluster of nerves that facilitate communication between various brain regions and houses the origins of several cranial nerves involved in facial movements and sensory information transfer.
- The medulla oblongata (English: Medulla oblongata) occupies the lowest part of the brain stem and functions as a regulatory center for vital functions such as heart and lung activity. It also plays a role in managing significant processes like breathing, sneezing, and swallowing.
Cerebellum
The cerebellum (English: Cerebellum) is located behind the brain stem and consists of a rounded mass connected to the brain by thick nerve tracts (English: Nerve tracts). It resembles the cerebrum, which serves as the brain’s primary bulk, and primarily aids in maintaining body balance and coordinating movements.
Injuries or diseases affecting the cerebellum can lead to neuromuscular disorders, particularly ataxia, which manifests through uncoordinated limb movements. Loss of integrated muscular control may result in body tremors and difficulties with standing.
Diencephalon
The diencephalon (English: Diencephalon) is located at the base of the brain and includes the following components:
- The thalamus (English: Thalamus) serves as a relay station for nerve signals entering the brain and is also involved in awareness, memory, and sleep regulation.
- The epithalamus (English: Epithalamus) acts as a connector between the limbic system (English: limbic system) and other brain regions. The limbic system is integral to emotional regulation, long-term memory, and behavioral responses.
- The hypothalamus (English: Hypothalamus) plays a crucial role in maintaining the balance of all bodily functions by regulating daily physiological cycles, such as sleep-wake patterns, appetite control, body temperature regulation, and hormone production and release.
Brain Size
The brain is one of the largest and most intricate organs in the human body, comprising over 100 billion neurons linked by trillions of synapses (English: Synapses). The human brain shares the fundamental structure typical of other mammals, yet it is the largest among vertebrates in relation to body weight. Weighing approximately 1.5 kilograms, it constitutes about 2% of total body weight. The average brain volume for males is approximately 1274 cm³, while for females, it is around 1131 cm³.