The Human Brain
The human brain is the command centre for the entire nervous system. It works like a computer to process various information that it receives as signals from the other sensory organs in the body and sends messages back to the body. While the human brain is the same in terms of structure as compared to other mammals, it is larger in terms of body size and better developed.
Weighing between 1-1.5 kg, the human brain is mostly made of neurons. There are anywhere between 86 billion-100 billion neurons in the human brain. The central nervous system is made up of the brain and the spinal cord. Basic functions like body movements, thoughts, emotions and more are controlled by the brain.
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The human brain consists of two types of tissues, gray and white matter. While gray matter makes up the bulk of the brain with various types of cells, white matter is made of axons that are responsible for connecting the various gray matter areas of the brain with each other.
Location of the Brain
The human brain is contained inside the skull. The skull comprises 22 bones, of which 8 are cranial bones and the remaining 14 are facial bones. The skull is also responsible for providing frontal, dorsal and lateral protection to the brain.
The brain is located inside the cranium and surrounded by cerebrospinal fluid, which fills up any hollow space on the brain surface and also circulates within the skull and the spinal cord. Specialized ependymal cells are responsible for producing about 500ml of cerebrospinal fluid every day.
The other functions that the cerebrospinal performs are:
The CSF (cerebrospinal fluid) acts as a cushion for the brain, lessening the impact of mechanical shocks and other jolts in the process.
It is responsible for providing immunological protection to the brain.
It provides buoyancy to the brain, almost negating the weight of the brain in its cushion of fluid.
Parts of the Human Brain
The human brain consists of various parts that include:
The Forebrain
The Midbrain
The Hindbrain
Each of these parts can be subdivided into various other parts as described below.
1. Forebrain- This refers to a human brain’s anterior part and controls various functions of the human body like temperature, reproduction, hunger, sleep, and emotions. The forebrain includes other parts like:
Cerebrum
This is the largest part of the brain which consists of the cerebral cortex of the brain and other subcortical structures. The cerebrum has two cerebral hemispheres. Dense, heavy bands of fiber, commonly known as the corpus callosum join the two cerebral hemispheres together.
Functions of the cerebrum include memory retention, consciousness, intelligence, thinking, hearing, vision and interpreting touch.
The cerebrum can be further subdivided into four sections, which are:
Frontal Lobe- This section is associated with movements, problem-solving abilities, reasoning, planning and various parts of speech.
Parietal Lobe- This section helps in perceiving stimuli, orientation, and movements.
Occipital Lobe- This is involved in visual processing.
Temporal Lobe- Relates to the recognition of memory, perception of auditory stimuli and speech.
The cerebrum also possesses an exterior part called the cerebral mantle, commonly known as the cortex. The cerebrum possesses an exterior part called the cerebral mantle, known as the cortex. The cortex has a large surface area since it is convoluted.
Other areas that are a part of the cerebrum:
Sensory areas- Help in receiving messages
Motor areas- Help the voluntary muscles act
Association areas- Help in connecting the sensory areas with the motor areas.
Thalamus
This is a part of the forebrain that is located above the brainstem. It is a small structure responsible for conveying sensory information from the various sense organs. It also helps in overall coordination and movement by transmitting motor information. The thalamus is contained within the cerebrum, in the limbic system, which helps in memory retention.
Hypothalamus
The hypothalamus is located below the thalamus and is a small yet essential part of the human brain. It is considered as the primary area of the brain performing the following functions:
The body temperature is regulated by the hypothalamus.
It receives impulses from various parts of the body.
Controls the emotional quotient and mood.
Controls the sense of smell and taste.
Controls blood pressure, appetite, heart rate, and peristalsis.
2. Midbrain- The midbrain is the central part of the brainstem. It is a fairly small area that consists of the:
Tectum
The tectum is the dorsal area of the midbrain and makes up for a small portion of the brain. It controls the reflex movements of the neck muscles, eye, and head. All sensory information from the ears to the cerebrum is relayed here. The tectum also acts as a passage for various neurons that move in and out of the cerebrum.
Tegmentum
The tegmentum is an area within the brainstem and forms the platform for the midbrain. It connects with the spinal cord, thalamus, and cerebral cortex. It has a complex structure that controls various reflex actions, body movements, sleep, attention and more.
3. Hindbrain- This is the central area of the human brain. It is composed of three regions that coordinate any process that is essential for survival, which includes motor learning and breathing. The hindbrain is made up of the following:
Cerebellum
It is the second-largest part of the brain located in the posterior area of the pons and the medulla. The transverse fissure and the tentorium cerebelli separate the cerebrum and the cerebellum. The outer surface of the cerebellum is the cortex; two hemispheres- the gray cortex on the outer portion and the white medulla inside make up the cerebellum.
The cerebellum also consists of cerebellar nuclei, cerebellar peduncles, and the anterior and posterior lobes. The cerebellum performs important functions like:
Transfer of information
Coordination of eye movement
Sense of equilibrium
Controlling the voluntary movements of the body
Coordination of skeletal movements that are directly related to the anterior and posterior lobes
Medulla
The medulla oblongata is in the lowest area of the brain. It is a small structure that controls the body’s autonomic functions like digestion, heartbeat. It also connects the cerebral cortex and the spinal cord and helps control the human body reflexes.
Pons
Present between the medulla oblongata and the midbrain, the pons is the most important structure of the brain stem. It relays signals between various parts of the brain including the spinal cord, lower cerebellum, midbrain, and cerebrum.
Some other functions of the pons include:
Regulating respiration frequency and magnitude
Controlling the sleep cycle
Transferring information between the motor cortex and the cerebellum
Helps in regulating sensations like taste and hearing
Conclusion
The human brain is the root of human intelligence. It controls the cognitive abilities of humans, their physiological and psychological functions, and communicates with the various other parts of the human body by sending signals via neurons. Details study materials, worksheets on this topic are available on the Vedantu Website.
FAQs on Human Brain
1. Why does a human brain perform certain functions?
The great longitudinal fissure separates the two hemispheres. Messages are transferred between the hemispheres via the corpus callosum, which connects the two halves of the brain. Cerebral hemispheres are divided into broad areas called lobes. A variety of functions are associated with each lobe:
Frontal Lobes: One of the largest parts of the brain is the frontal lobe. They are located at the frontal lobe of the brain, as their name indicates. The coordination of these behaviours includes motor skills, problem-solving, judgment, planning, and attention. In addition to handling emotions, personality, and temper, the frontal lobes also regulate movement.
These are the Prefrontal Lobes: Located behind the frontal lobes, the parietal lobes serve as extensions of the brain. In other words, they interpret and organize information from sensory sources.
These areas are called the temporal lobes. The auditory cortex is situated within these areas. A tympanic membrane is located at a level equal to the level of the ears on either side of the head. The auditory system coordinates several functions, including hearing, visual memories (such as recognizing faces), verbal memories (such as understanding language), and interpreting emotional reactions.
The auditory system coordinates several functions, including hearing, visual memories (such as recognizing faces), verbal memories (such as understanding language), and interpreting emotional reactions.
Hearing, visual memories (such as recognizing faces), verbal memories (such as understanding language) and interpreting emotional reactions are all coordinated by the auditory system.
Occipital lobes. Opposite the frontal lobes, the occipital lobes are located in the back of the brain. Reading and recognizing colours and shapes is heavily reliant on them.
2. After the death of the person, does the brain stay alive?
The BRAIN Initiative and neuroscience research at large is celebrating an important milestone in April: A Yale School of Medicine researcher has published a report in Nature showing that his team has restored circulation and some cellular functions to pig brains four hours after the animals were killed, Live Science previously reported. Researchers were able to challenge the commonly held belief that brain cells are irreversibly damaged after the heart stops beating. It was not the researchers' intention to observe signs of consciousness in brain tissue, and they didn't make any attempts to do so; on the contrary, they injected pig brains with chemicals that mimicked blood flow while blocking neurons from firing. Scientists confirmed that they did not bring the pig brains back to life. Their cellular activity, however, was restored.
3. In what ways does the brain differ from other organs?
An injured or malfunctioning brain can pose problems as it is a complex and finely calibrated machine. The chances of suffering from neurological damage are among one in five people. The list includes stroke, epilepsy, cerebral palsy, and dementia, among others.
There are several causes of dementia, but Alzheimer's disease is the most common. It is characterized by short-term memory loss, disorientation, and mood swings over time. The number of Americans diagnosed with it is on the rise, and it is the sixth leading cause of death in the country. The hippocampus and the prefrontal cortex of the brain are involved in anxiety disorders.
ADHD, or attention-deficit/hyperactivity disorder, affects both adults and children. Children are more likely to be diagnosed with the condition than adults. Hyperactivity and an inability to concentrate make ADHD more noticeable in children than in adults. Mental health issues such as depression are also common among children. Anxiety is often a side effect of this condition, which leads to disability worldwide. Register Vedantu.com and download free PDF study notes on the human brain.
4. In addition to the brain's major parts, what are the other components?
There are several key brain parts besides the cerebral cortex:
Ventricular System: There is no such thing as a solid brain. Instead, there are fluid-filled cavities known as ventricles inside the brain. The ventricles are responsible for supplying the brain with nutrients. Cerebrospinal fluid is a watery liquid that surrounds and protects the brain, and it is produced and processed by the ventricular system.
Cranial Nerves: Twelve pairs of cranial nerves are also located in the brain. Every pair controls a different function of the body.
The smell is produced by the olfactory nerve
which is connected to the optic nerve.
Eye movement and eyelid opening are oculomotor functions.
To clear Eye movement and eyelid opening.
5. Is brain size correlated with intelligence?
The overall size of non-human animals' brains is not related to their intelligence. Humans are considered to be more intelligent than sperm whales, even though sperm whales have brains that are more than five times heavier than humans. In general, the ratio of brain size to body size is a more accurate way of measuring an animal's intelligence, but even this only places humans ahead of animals. The size of one's brain does not correlate with intelligence in humans. There are some geniuses in their field who have smaller-than-average brains, while there are others who have larger brains.
