The Brain: Anatomy and Function



Humans have developed cognitive capacities that distinguish them from other living organisms. Our brain performs several unexpected activities. To begin with, it is heavy, weighing 3 pounds, which is significantly more substantial than other creatures when compared to human physical size. According to research, specific regions in the human brain are allocated for language processes. What are the names of several areas of the brain? How do they collaborate in order to do basic and complicated tasks? This article investigates the many sections of the brain and their functions.

The human brain is the body's command center, a complex organ responsible for practically all of our body's operations. It controls activities like thinking, memory, sensory perception, motor movements of the body, and all life-sustaining systems such as breathing, homeostasis, digestion, and so on. The central nervous system is composed of the brain and the spinal cord work together.

Development of Brain

The expanded cranial portion of the neural tube gives rise to the brain. The growing brain's cavity displays three dilatations at the end of the fourth week. The prosencephalon (forebrain vesicle), mesencephalon (midbrain vesicle), and rhombencephalon (hindbrain vesicle) are located cranially. The prosencephalon is separated into two parts: the telencephalon and the diencephalon. The telencephalon comprises telencephalic vesicles on the right and left sides. The rhombencephalon is further separated into cranial (metencephalon) and caudal (myelencephalon).

The prosencephalon, mesencephalon, and rhombencephalon are positioned craniocaudally at first. The presence of many flexures significantly alters their relative location. They are as follows −

  • The cervical flexure, located at the rhombencephalon-spinal cord junction.

  • The mesencephalic flexure (or cephalic flexure) in the midbrain area.

  • The pontine flexure occurs in the middle of the rhombencephalon and divides it into the metencephalon and myelencephalon.

  • The telencephalic flexure develops much later between the telencephalon and diencephalon.

As in adults, these flexures lead to the orientation of distinct brain areas.

Functions of the Brain

The brain is primarily responsible for communication. It accomplishes this by transmitting and receiving signals. These messages are sent throughout the body via electrical and chemical impulses. These signals are in charge of a variety of processes. Furthermore, the brain's role is to comprehend each of them. For example, the brain perceives pain when the finger pricks itself. Some messages are kept in the brain, while others are transmitted back to the brain via the spine and the enormous network of nerves that runs throughout the body. This function is carried out effectively by the neurological system. Billions of neurons support this mechanism. How can the brain do such complicated tasks daily? Our brain contains several structures, each of which serves a specific purpose.

The Anatomy of the Human Brain

We may examine the varying degrees of the structural development of the brain from its earliest to most recent evolutionary forms. The brain may be split into three parts: the brainstem, the cerebrum, and the cerebellum. For the convenience of study, the brain may be divided into three parts: the hindbrain, the midbrain, and the forebrain.

  • Hindbrain − This part contains the medulla oblongata, Pons, and cerebellum.

  • Midbrain − With various distinct neuron clusters (nuclei and colliculi), neuronal pathways, and other structures, the midbrain is a tremendously complicated structure.

  • Forebrain − This part consists of the hypothalamus, the limbic system, and the cerebrum, which consists of the cerebral cortex.

What are the Functions of Various Brain Structures?

Each of the structures has important functions. They are discussed below.

Parts of the Hindbrain

It includes −

  • Medulla Oblongata − The medulla is large above where it links the pons and narrows below where it joins the spinal cord. It has a length of around 3 cm and a width of about 2 cm at its widest point. The medulla-spinal cord junction is located at the level of the top border of the atlas vertebra. The medulla is separated from the bulging ventral region of the pons by a deep groove. The medulla is split into two sections: a lower closed section surrounding the central canal and an upper open section corresponding to the fourth ventricle's lower half. The medulla's surface is defined by a series of fissures or sulci that split it into many areas.

  • Pons − Pons is a portion of the brainstem between the medulla and the midbrain. It is located on the clivus, anterior to the cerebellum, in the posterior cranial fossa. Pons translates to "the bridge." It is so named because its transverse fibers, which comprise the middle cerebellar peduncle, operate as a conduit for the transit of fibers from one side of the cerebellum to the other. The pons contains the nuclei of the cranial nerves V (trigeminal), VI (abducent), VII (facial), and VIII (vestibulocochlear).

  • Cerebellum − The cerebellum (sometimes known as the tiny brain) is located in the posterior cranial fossa. The cerebellum weighs roughly 150 g in an adult, which is approximately 10% of the total weight of the cerebral hemispheres. The cerebellum, like the cerebrum, includes a superficial layer of grey matter called the cerebellar cortex. Because of multiple fissures, the cerebellar cortex is far more widespread than its size implies. The surface area of the cerebellar cortex is believed to be roughly half that of the cerebral cortex. The cerebellum is located between the pons and the medulla. It is separated from the cerebrum by a dura mater fold known as the tentorium cerebelli. The fourth ventricle is located anteriorly, between the cerebellum (behind) and the pons and medulla. A transverse cleft stretches from the ventricular cavity into the cerebellum. This fissure is cranially bordered by the superior (or anterior) medullary velum, a white matter lamina.

Parts of the Midbrain

The midbrain is the brainstem's highest region, linking the hindbrain to the forebrain. It is around 2 cm long. The cerebral aqueduct, its cavity, links the third and fourth ventricles. The nucleus of origin for cranial nerves III (oculomotor) and IV are located in the midbrain (trochlear). In addition to the cranial nerve nuclei, the midbrain contains nuclei that coordinate eyeball movement in response to visual inputs, which are positioned at superior colliculi. The inferior colliculi include nuclei that coordinate head and trunk motions in response to auditory inputs.

The tectum is the portion of the brain that is dorsal to a transverse line drawn through the cerebral aqueduct. It is made comprised of the superior and inferior colliculi on both sides. As a result, it is also known as corpora quadrigemina. The cerebral peduncles are left with right and left portions that lie ventral to the transverse line. Each peduncle is made up of three sections. The crus cerebri (also known as the basis pedunculi), the substantia nigra, and the tegmentum are anterior to posterior.

Parts of the Forebrain

It includes −

It is regarded as the most significant component of the brain since it controls all motor, emotional, and cognitive functions. We will talk about the hypothalamus, thalamus, limbic system, and cerebrum—the forebrain's four principal regions.

  • Thalamus − The thalamus (or dorsal thalamus) is a huge egg-shaped mass of grey matter located just lateral to the third ventricle. It has two ends (or poles) called anterior and posterior, as well as four surfaces called superior, inferior, medial, and lateral. The posterior limit of the interventricular foramen is formed by the anterior end (or pole).

  • Hypothalamus − The hypothalamus is a component of the diencephalon, namely the pars entrails diencephalic. It is located underneath the thalamus and is separated from it by the hypothalamic sulcus. The hypothalamus is mostly concealed. However, certain sections of the hypothalamus may be seen on the brain's exterior (ventral) surface. These visible hypothalamic components are found in the interpeduncular fossa and compose the bottom of the third ventricle. It constitutes the lateral wall of the third ventricle below the level of the hypothalamic sulcus on the medial side.

  • Limbic System − The limbic system consists of the limbic lobe and the components that relate to it. Broca invented the term "limbic lobe" in 1878 to describe structures on the medial and inferior surfaces of the cerebral hemispheres that form a "border or ring" surrounding the brainstem. The limbic system comprises many cortical and subcortical regions that create a ring-like structure around the top of the brainstem. The term limbic system has previously been used to describe particular brain parts thought to play a key role in regulating visceral activity. The olfactory system in humans is not only concerned with the scent but also stimulates other brain systems for emotional behavior, making it a component of the limbic system.

  • Cerebrum − Gray matter (the cerebral cortex) and white matter make up the cerebrum, the front of the brain. The cerebrum, the biggest component of the brain, controls temperature and initiates and coordinates movement. Speech, judgment, thinking and reasoning, problem-solving, emotions, and learning are all made possible by different regions of the cerebral cortex. Other functions deal with the senses of sight, sound, touch, and others.

Conclusion

The human brain is a wonderful and complex organ, and it has evolved to perform various functions that are unique to humans. Brain imaging studies contrasting the brains of humans and other primates reveal that humans have more fibers connecting the brain regions involved in such human-specific skills as language, tool building, reasoning, and social cognition, in addition to having more neurons in the association cortex. The brain has several structures that perform a variety of complex behaviors that humans showcase.


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